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* [dm-devel] merge struct block_device and struct hd_struct v2
@ 2020-11-24 13:27 Christoph Hellwig
  2020-11-24 13:27 ` [dm-devel] [PATCH 01/45] blk-cgroup: fix a hd_struct leak in blkcg_fill_root_iostats Christoph Hellwig
                   ` (44 more replies)
  0 siblings, 45 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Hi Jens,

this series cleans up our main per-device node data structure by merging
the block_device and hd_struct data structures that have the same scope,
but different life times.  The main effect (besides removing lots of
code) is that instead of having two device sizes that need complex
synchronization there is just one now.

Note that this now includes the previous "misc cleanups" series as I had
to fix up a thing in there with the changed patch ordering.

The first patch already is in 5.10-rc, but not in for-5.11/block

A git tree is available here:

    git://git.infradead.org/users/hch/block.git bdev-lookup

Gitweb:

    http://git.infradead.org/users/hch/block.git/shortlog/refs/heads/bdev-lookup

Changes since v1:
 - spelling fixes
 - fix error unwinding in __alloc_disk_node
 - use bdev_is_partition in a few more places
 - don't send the RESIZE=1 uevent for hidden gendisks
 - rename __bdget_disk to disk_find_part
 - drop a bcache patch
 - some patch reordering
 - add more refactoring
 - use rcu protection to prevent racing with a disk going away
   in blkdev_get
 - split up some of the big patches into many small ones
 - clean up the freeze_bdev interface

Diffstat:
 block/bio.c                                  |    6 
 block/blk-cgroup.c                           |   50 -
 block/blk-core.c                             |   68 +-
 block/blk-flush.c                            |    2 
 block/blk-iocost.c                           |   36 -
 block/blk-lib.c                              |    2 
 block/blk-merge.c                            |    2 
 block/blk-mq.c                               |    9 
 block/blk-mq.h                               |    7 
 block/blk.h                                  |   84 ---
 block/genhd.c                                |  467 ++++-------------
 block/ioctl.c                                |   14 
 block/partitions/core.c                      |  252 +++------
 drivers/block/drbd/drbd_receiver.c           |    2 
 drivers/block/drbd/drbd_worker.c             |    3 
 drivers/block/loop.c                         |   24 
 drivers/block/mtip32xx/mtip32xx.c            |   15 
 drivers/block/mtip32xx/mtip32xx.h            |    2 
 drivers/block/nbd.c                          |    6 
 drivers/block/xen-blkback/common.h           |    4 
 drivers/block/xen-blkfront.c                 |   20 
 drivers/block/zram/zram_drv.c                |   87 ---
 drivers/block/zram/zram_drv.h                |    1 
 drivers/md/bcache/request.c                  |    4 
 drivers/md/bcache/super.c                    |   29 -
 drivers/md/dm-core.h                         |    7 
 drivers/md/dm-table.c                        |    9 
 drivers/md/dm.c                              |   45 -
 drivers/md/md.c                              |    8 
 drivers/mtd/mtdsuper.c                       |   17 
 drivers/nvme/target/admin-cmd.c              |   20 
 drivers/s390/block/dasd.c                    |    8 
 drivers/s390/block/dasd_ioctl.c              |    9 
 drivers/scsi/scsicam.c                       |    2 
 drivers/target/target_core_file.c            |    6 
 drivers/target/target_core_pscsi.c           |    7 
 drivers/usb/gadget/function/storage_common.c |    8 
 fs/block_dev.c                               |  730 +++++++++------------------
 fs/btrfs/sysfs.c                             |   15 
 fs/btrfs/volumes.c                           |   13 
 fs/buffer.c                                  |    2 
 fs/ext4/ioctl.c                              |    2 
 fs/ext4/super.c                              |   18 
 fs/ext4/sysfs.c                              |   10 
 fs/f2fs/checkpoint.c                         |    5 
 fs/f2fs/f2fs.h                               |    2 
 fs/f2fs/file.c                               |   14 
 fs/f2fs/super.c                              |    8 
 fs/f2fs/sysfs.c                              |    9 
 fs/inode.c                                   |    3 
 fs/internal.h                                |    7 
 fs/io_uring.c                                |   10 
 fs/pipe.c                                    |    5 
 fs/pstore/blk.c                              |    2 
 fs/quota/quota.c                             |   40 +
 fs/statfs.c                                  |    2 
 fs/super.c                                   |   86 ---
 fs/xfs/xfs_fsops.c                           |    7 
 include/linux/blk-cgroup.h                   |    4 
 include/linux/blk_types.h                    |   24 
 include/linux/blkdev.h                       |   27 
 include/linux/fs.h                           |    5 
 include/linux/genhd.h                        |  110 ----
 include/linux/part_stat.h                    |   45 -
 init/do_mounts.c                             |  271 ++++------
 kernel/trace/blktrace.c                      |   54 -
 mm/filemap.c                                 |   13 
 67 files changed, 957 insertions(+), 1928 deletions(-)

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 01/45] blk-cgroup: fix a hd_struct leak in blkcg_fill_root_iostats
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-25  6:41   ` Hannes Reinecke
  2020-11-24 13:27 ` [dm-devel] [PATCH 02/45] filemap: consistently use ->f_mapping over ->i_mapping Christoph Hellwig
                   ` (43 subsequent siblings)
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

disk_get_part needs to be paired with a disk_put_part.

Fixes: ef45fe470e1 ("blk-cgroup: show global disk stats in root cgroup io.stat")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Acked-by: Tejun Heo <tj@kernel.org>
---
 block/blk-cgroup.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index c68bdf58c9a6e1..54fbe1e80cc41a 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -849,6 +849,7 @@ static void blkcg_fill_root_iostats(void)
 			blkg_iostat_set(&blkg->iostat.cur, &tmp);
 			u64_stats_update_end(&blkg->iostat.sync);
 		}
+		disk_put_part(part);
 	}
 }
 
-- 
2.29.2

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 02/45] filemap: consistently use ->f_mapping over ->i_mapping
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
  2020-11-24 13:27 ` [dm-devel] [PATCH 01/45] blk-cgroup: fix a hd_struct leak in blkcg_fill_root_iostats Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 13:53   ` Matthew Wilcox
                     ` (2 more replies)
  2020-11-24 13:27 ` [dm-devel] [PATCH 03/45] fs: remove get_super_thawed and get_super_exclusive_thawed Christoph Hellwig
                   ` (42 subsequent siblings)
  44 siblings, 3 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Use file->f_mapping in all remaining places that have a struct file
available to properly handle the case where inode->i_mapping !=
file_inode(file)->i_mapping.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 mm/filemap.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index d5e7c2029d16b4..4f583489aa3c2a 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2886,14 +2886,14 @@ EXPORT_SYMBOL(filemap_map_pages);
 
 vm_fault_t filemap_page_mkwrite(struct vm_fault *vmf)
 {
+	struct address_space *mapping = vmf->vma->vm_file->f_mapping;
 	struct page *page = vmf->page;
-	struct inode *inode = file_inode(vmf->vma->vm_file);
 	vm_fault_t ret = VM_FAULT_LOCKED;
 
-	sb_start_pagefault(inode->i_sb);
+	sb_start_pagefault(mapping->host->i_sb);
 	file_update_time(vmf->vma->vm_file);
 	lock_page(page);
-	if (page->mapping != inode->i_mapping) {
+	if (page->mapping != mapping) {
 		unlock_page(page);
 		ret = VM_FAULT_NOPAGE;
 		goto out;
@@ -2906,7 +2906,7 @@ vm_fault_t filemap_page_mkwrite(struct vm_fault *vmf)
 	set_page_dirty(page);
 	wait_for_stable_page(page);
 out:
-	sb_end_pagefault(inode->i_sb);
+	sb_end_pagefault(mapping->host->i_sb);
 	return ret;
 }
 
@@ -3149,10 +3149,9 @@ void dio_warn_stale_pagecache(struct file *filp)
 {
 	static DEFINE_RATELIMIT_STATE(_rs, 86400 * HZ, DEFAULT_RATELIMIT_BURST);
 	char pathname[128];
-	struct inode *inode = file_inode(filp);
 	char *path;
 
-	errseq_set(&inode->i_mapping->wb_err, -EIO);
+	errseq_set(&filp->f_mapping->wb_err, -EIO);
 	if (__ratelimit(&_rs)) {
 		path = file_path(filp, pathname, sizeof(pathname));
 		if (IS_ERR(path))
@@ -3179,7 +3178,7 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
 
 	if (iocb->ki_flags & IOCB_NOWAIT) {
 		/* If there are pages to writeback, return */
-		if (filemap_range_has_page(inode->i_mapping, pos,
+		if (filemap_range_has_page(file->f_mapping, pos,
 					   pos + write_len - 1))
 			return -EAGAIN;
 	} else {
-- 
2.29.2

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 03/45] fs: remove get_super_thawed and get_super_exclusive_thawed
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
  2020-11-24 13:27 ` [dm-devel] [PATCH 01/45] blk-cgroup: fix a hd_struct leak in blkcg_fill_root_iostats Christoph Hellwig
  2020-11-24 13:27 ` [dm-devel] [PATCH 02/45] filemap: consistently use ->f_mapping over ->i_mapping Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-25  6:42   ` Hannes Reinecke
  2020-11-25 12:19   ` Jan Kara
  2020-11-24 13:27 ` [dm-devel] [PATCH 04/45] fs: simplify freeze_bdev/thaw_bdev Christoph Hellwig
                   ` (41 subsequent siblings)
  44 siblings, 2 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Just open code the wait in the only caller of both functions.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/internal.h      |  2 ++
 fs/quota/quota.c   | 31 +++++++++++++++++++++-------
 fs/super.c         | 51 ++--------------------------------------------
 include/linux/fs.h |  4 +---
 4 files changed, 29 insertions(+), 59 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index a7cd0f64faa4ab..47be21dfeebef5 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -114,7 +114,9 @@ extern struct file *alloc_empty_file_noaccount(int, const struct cred *);
  */
 extern int reconfigure_super(struct fs_context *);
 extern bool trylock_super(struct super_block *sb);
+struct super_block *__get_super(struct block_device *bdev, bool excl);
 extern struct super_block *user_get_super(dev_t);
+void put_super(struct super_block *sb);
 extern bool mount_capable(struct fs_context *);
 
 /*
diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index 9af95c7a0bbe3c..f3d32b0d9008f2 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -20,6 +20,7 @@
 #include <linux/writeback.h>
 #include <linux/nospec.h>
 #include "compat.h"
+#include "../internal.h"
 
 static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
 				     qid_t id)
@@ -868,6 +869,7 @@ static struct super_block *quotactl_block(const char __user *special, int cmd)
 	struct block_device *bdev;
 	struct super_block *sb;
 	struct filename *tmp = getname(special);
+	bool excl = false, thawed = false;
 
 	if (IS_ERR(tmp))
 		return ERR_CAST(tmp);
@@ -875,17 +877,32 @@ static struct super_block *quotactl_block(const char __user *special, int cmd)
 	putname(tmp);
 	if (IS_ERR(bdev))
 		return ERR_CAST(bdev);
-	if (quotactl_cmd_onoff(cmd))
-		sb = get_super_exclusive_thawed(bdev);
-	else if (quotactl_cmd_write(cmd))
-		sb = get_super_thawed(bdev);
-	else
-		sb = get_super(bdev);
+
+	if (quotactl_cmd_onoff(cmd)) {
+		excl = true;
+		thawed = true;
+	} else if (quotactl_cmd_write(cmd)) {
+		thawed = true;
+	}
+
+retry:
+	sb = __get_super(bdev, excl);
+	if (thawed && sb && sb->s_writers.frozen != SB_UNFROZEN) {
+		if (excl)
+			up_write(&sb->s_umount);
+		else
+			up_read(&sb->s_umount);
+		wait_event(sb->s_writers.wait_unfrozen,
+			   sb->s_writers.frozen == SB_UNFROZEN);
+		put_super(sb);
+		goto retry;
+	}
+
 	bdput(bdev);
 	if (!sb)
 		return ERR_PTR(-ENODEV);
-
 	return sb;
+
 #else
 	return ERR_PTR(-ENODEV);
 #endif
diff --git a/fs/super.c b/fs/super.c
index 98bb0629ee108e..343e5c1e538d2a 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -307,7 +307,7 @@ static void __put_super(struct super_block *s)
  *	Drops a temporary reference, frees superblock if there's no
  *	references left.
  */
-static void put_super(struct super_block *sb)
+void put_super(struct super_block *sb)
 {
 	spin_lock(&sb_lock);
 	__put_super(sb);
@@ -740,7 +740,7 @@ void iterate_supers_type(struct file_system_type *type,
 
 EXPORT_SYMBOL(iterate_supers_type);
 
-static struct super_block *__get_super(struct block_device *bdev, bool excl)
+struct super_block *__get_super(struct block_device *bdev, bool excl)
 {
 	struct super_block *sb;
 
@@ -789,53 +789,6 @@ struct super_block *get_super(struct block_device *bdev)
 }
 EXPORT_SYMBOL(get_super);
 
-static struct super_block *__get_super_thawed(struct block_device *bdev,
-					      bool excl)
-{
-	while (1) {
-		struct super_block *s = __get_super(bdev, excl);
-		if (!s || s->s_writers.frozen == SB_UNFROZEN)
-			return s;
-		if (!excl)
-			up_read(&s->s_umount);
-		else
-			up_write(&s->s_umount);
-		wait_event(s->s_writers.wait_unfrozen,
-			   s->s_writers.frozen == SB_UNFROZEN);
-		put_super(s);
-	}
-}
-
-/**
- *	get_super_thawed - get thawed superblock of a device
- *	@bdev: device to get the superblock for
- *
- *	Scans the superblock list and finds the superblock of the file system
- *	mounted on the device. The superblock is returned once it is thawed
- *	(or immediately if it was not frozen). %NULL is returned if no match
- *	is found.
- */
-struct super_block *get_super_thawed(struct block_device *bdev)
-{
-	return __get_super_thawed(bdev, false);
-}
-EXPORT_SYMBOL(get_super_thawed);
-
-/**
- *	get_super_exclusive_thawed - get thawed superblock of a device
- *	@bdev: device to get the superblock for
- *
- *	Scans the superblock list and finds the superblock of the file system
- *	mounted on the device. The superblock is returned once it is thawed
- *	(or immediately if it was not frozen) and s_umount semaphore is held
- *	in exclusive mode. %NULL is returned if no match is found.
- */
-struct super_block *get_super_exclusive_thawed(struct block_device *bdev)
-{
-	return __get_super_thawed(bdev, true);
-}
-EXPORT_SYMBOL(get_super_exclusive_thawed);
-
 /**
  * get_active_super - get an active reference to the superblock of a device
  * @bdev: device to get the superblock for
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 8667d0cdc71e76..a61df0dd4f1989 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1409,7 +1409,7 @@ enum {
 
 struct sb_writers {
 	int				frozen;		/* Is sb frozen? */
-	wait_queue_head_t		wait_unfrozen;	/* for get_super_thawed() */
+	wait_queue_head_t		wait_unfrozen;	/* wait for thaw */
 	struct percpu_rw_semaphore	rw_sem[SB_FREEZE_LEVELS];
 };
 
@@ -3132,8 +3132,6 @@ extern struct file_system_type *get_filesystem(struct file_system_type *fs);
 extern void put_filesystem(struct file_system_type *fs);
 extern struct file_system_type *get_fs_type(const char *name);
 extern struct super_block *get_super(struct block_device *);
-extern struct super_block *get_super_thawed(struct block_device *);
-extern struct super_block *get_super_exclusive_thawed(struct block_device *bdev);
 extern struct super_block *get_active_super(struct block_device *bdev);
 extern void drop_super(struct super_block *sb);
 extern void drop_super_exclusive(struct super_block *sb);
-- 
2.29.2

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 04/45] fs: simplify freeze_bdev/thaw_bdev
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (2 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 03/45] fs: remove get_super_thawed and get_super_exclusive_thawed Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-25  6:07   ` Chao Yu
  2020-11-25 12:29   ` Jan Kara
  2020-11-24 13:27 ` [dm-devel] [PATCH 05/45] mtip32xx: remove the call to fsync_bdev on removal Christoph Hellwig
                   ` (40 subsequent siblings)
  44 siblings, 2 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Store the frozen superblock in struct block_device to avoid the awkward
interface that can return a sb only used a cookie, an ERR_PTR or NULL.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/md/dm-core.h      |  5 -----
 drivers/md/dm.c           | 20 ++++++--------------
 fs/block_dev.c            | 39 ++++++++++++++++-----------------------
 fs/buffer.c               |  2 +-
 fs/ext4/ioctl.c           |  2 +-
 fs/f2fs/file.c            | 14 +++++---------
 fs/xfs/xfs_fsops.c        |  7 ++-----
 include/linux/blk_types.h |  1 +
 include/linux/blkdev.h    |  4 ++--
 9 files changed, 34 insertions(+), 60 deletions(-)

diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h
index d522093cb39dda..aace147effcacb 100644
--- a/drivers/md/dm-core.h
+++ b/drivers/md/dm-core.h
@@ -96,11 +96,6 @@ struct mapped_device {
 	 */
 	struct workqueue_struct *wq;
 
-	/*
-	 * freeze/thaw support require holding onto a super block
-	 */
-	struct super_block *frozen_sb;
-
 	/* forced geometry settings */
 	struct hd_geometry geometry;
 
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 54739f1b579bc8..50541d336c719b 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2392,27 +2392,19 @@ static int lock_fs(struct mapped_device *md)
 {
 	int r;
 
-	WARN_ON(md->frozen_sb);
+	WARN_ON(test_bit(DMF_FROZEN, &md->flags));
 
-	md->frozen_sb = freeze_bdev(md->bdev);
-	if (IS_ERR(md->frozen_sb)) {
-		r = PTR_ERR(md->frozen_sb);
-		md->frozen_sb = NULL;
-		return r;
-	}
-
-	set_bit(DMF_FROZEN, &md->flags);
-
-	return 0;
+	r = freeze_bdev(md->bdev);
+	if (!r)
+		set_bit(DMF_FROZEN, &md->flags);
+	return r;
 }
 
 static void unlock_fs(struct mapped_device *md)
 {
 	if (!test_bit(DMF_FROZEN, &md->flags))
 		return;
-
-	thaw_bdev(md->bdev, md->frozen_sb);
-	md->frozen_sb = NULL;
+	thaw_bdev(md->bdev);
 	clear_bit(DMF_FROZEN, &md->flags);
 }
 
diff --git a/fs/block_dev.c b/fs/block_dev.c
index d8664f5c1ff669..60492620d51866 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -548,55 +548,47 @@ EXPORT_SYMBOL(fsync_bdev);
  * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
  * actually.
  */
-struct super_block *freeze_bdev(struct block_device *bdev)
+int freeze_bdev(struct block_device *bdev)
 {
 	struct super_block *sb;
 	int error = 0;
 
 	mutex_lock(&bdev->bd_fsfreeze_mutex);
-	if (++bdev->bd_fsfreeze_count > 1) {
-		/*
-		 * We don't even need to grab a reference - the first call
-		 * to freeze_bdev grab an active reference and only the last
-		 * thaw_bdev drops it.
-		 */
-		sb = get_super(bdev);
-		if (sb)
-			drop_super(sb);
-		mutex_unlock(&bdev->bd_fsfreeze_mutex);
-		return sb;
-	}
+	if (++bdev->bd_fsfreeze_count > 1)
+		goto done;
 
 	sb = get_active_super(bdev);
 	if (!sb)
-		goto out;
+		goto sync;
 	if (sb->s_op->freeze_super)
 		error = sb->s_op->freeze_super(sb);
 	else
 		error = freeze_super(sb);
+	deactivate_super(sb);
+
 	if (error) {
-		deactivate_super(sb);
 		bdev->bd_fsfreeze_count--;
-		mutex_unlock(&bdev->bd_fsfreeze_mutex);
-		return ERR_PTR(error);
+		goto done;
 	}
-	deactivate_super(sb);
- out:
+	bdev->bd_fsfreeze_sb = sb;
+
+sync:
 	sync_blockdev(bdev);
+done:
 	mutex_unlock(&bdev->bd_fsfreeze_mutex);
-	return sb;	/* thaw_bdev releases s->s_umount */
+	return error;	/* thaw_bdev releases s->s_umount */
 }
 EXPORT_SYMBOL(freeze_bdev);
 
 /**
  * thaw_bdev  -- unlock filesystem
  * @bdev:	blockdevice to unlock
- * @sb:		associated superblock
  *
  * Unlocks the filesystem and marks it writeable again after freeze_bdev().
  */
-int thaw_bdev(struct block_device *bdev, struct super_block *sb)
+int thaw_bdev(struct block_device *bdev)
 {
+	struct super_block *sb;
 	int error = -EINVAL;
 
 	mutex_lock(&bdev->bd_fsfreeze_mutex);
@@ -607,6 +599,7 @@ int thaw_bdev(struct block_device *bdev, struct super_block *sb)
 	if (--bdev->bd_fsfreeze_count > 0)
 		goto out;
 
+	sb = bdev->bd_fsfreeze_sb;
 	if (!sb)
 		goto out;
 
@@ -618,7 +611,7 @@ int thaw_bdev(struct block_device *bdev, struct super_block *sb)
 		bdev->bd_fsfreeze_count++;
 out:
 	mutex_unlock(&bdev->bd_fsfreeze_mutex);
-	return error;
+	return 0;
 }
 EXPORT_SYMBOL(thaw_bdev);
 
diff --git a/fs/buffer.c b/fs/buffer.c
index 23f645657488ba..a7595ada9400ff 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -523,7 +523,7 @@ static int osync_buffers_list(spinlock_t *lock, struct list_head *list)
 
 void emergency_thaw_bdev(struct super_block *sb)
 {
-	while (sb->s_bdev && !thaw_bdev(sb->s_bdev, sb))
+	while (sb->s_bdev && !thaw_bdev(sb->s_bdev))
 		printk(KERN_WARNING "Emergency Thaw on %pg\n", sb->s_bdev);
 }
 
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index f0381876a7e5b0..524e134324475e 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -624,7 +624,7 @@ static int ext4_shutdown(struct super_block *sb, unsigned long arg)
 	case EXT4_GOING_FLAGS_DEFAULT:
 		freeze_bdev(sb->s_bdev);
 		set_bit(EXT4_FLAGS_SHUTDOWN, &sbi->s_ext4_flags);
-		thaw_bdev(sb->s_bdev, sb);
+		thaw_bdev(sb->s_bdev);
 		break;
 	case EXT4_GOING_FLAGS_LOGFLUSH:
 		set_bit(EXT4_FLAGS_SHUTDOWN, &sbi->s_ext4_flags);
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index ee861c6d9ff026..a9fc482a0e60a5 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2230,16 +2230,12 @@ static int f2fs_ioc_shutdown(struct file *filp, unsigned long arg)
 
 	switch (in) {
 	case F2FS_GOING_DOWN_FULLSYNC:
-		sb = freeze_bdev(sb->s_bdev);
-		if (IS_ERR(sb)) {
-			ret = PTR_ERR(sb);
+		ret = freeze_bdev(sb->s_bdev);
+		if (ret)
 			goto out;
-		}
-		if (sb) {
-			f2fs_stop_checkpoint(sbi, false);
-			set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
-			thaw_bdev(sb->s_bdev, sb);
-		}
+		f2fs_stop_checkpoint(sbi, false);
+		set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
+		thaw_bdev(sb->s_bdev);
 		break;
 	case F2FS_GOING_DOWN_METASYNC:
 		/* do checkpoint only */
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index ef1d5bb88b93ab..b7c5783a031c69 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -433,13 +433,10 @@ xfs_fs_goingdown(
 {
 	switch (inflags) {
 	case XFS_FSOP_GOING_FLAGS_DEFAULT: {
-		struct super_block *sb = freeze_bdev(mp->m_super->s_bdev);
-
-		if (sb && !IS_ERR(sb)) {
+		if (!freeze_bdev(mp->m_super->s_bdev)) {
 			xfs_force_shutdown(mp, SHUTDOWN_FORCE_UMOUNT);
-			thaw_bdev(sb->s_bdev, sb);
+			thaw_bdev(mp->m_super->s_bdev);
 		}
-
 		break;
 	}
 	case XFS_FSOP_GOING_FLAGS_LOGFLUSH:
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index d9b69bbde5cc54..ebfb4e7c1fd125 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -46,6 +46,7 @@ struct block_device {
 	int			bd_fsfreeze_count;
 	/* Mutex for freeze */
 	struct mutex		bd_fsfreeze_mutex;
+	struct super_block	*bd_fsfreeze_sb;
 } __randomize_layout;
 
 /*
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 05b346a68c2eee..12810a19edebc4 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -2020,7 +2020,7 @@ static inline int sync_blockdev(struct block_device *bdev)
 #endif
 int fsync_bdev(struct block_device *bdev);
 
-struct super_block *freeze_bdev(struct block_device *bdev);
-int thaw_bdev(struct block_device *bdev, struct super_block *sb);
+int freeze_bdev(struct block_device *bdev);
+int thaw_bdev(struct block_device *bdev);
 
 #endif /* _LINUX_BLKDEV_H */
-- 
2.29.2

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 05/45] mtip32xx: remove the call to fsync_bdev on removal
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (3 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 04/45] fs: simplify freeze_bdev/thaw_bdev Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-25 12:31   ` Jan Kara
  2020-11-24 13:27 ` [dm-devel] [PATCH 06/45] zram: remove the claim mechanism Christoph Hellwig
                   ` (39 subsequent siblings)
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

del_gendisk already calls fsync_bdev for every partition, no need
to do this twice.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/block/mtip32xx/mtip32xx.c | 15 ---------------
 drivers/block/mtip32xx/mtip32xx.h |  2 --
 2 files changed, 17 deletions(-)

diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
index 153e2cdecb4d40..53ac59d19ae530 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -3687,7 +3687,6 @@ static int mtip_block_initialize(struct driver_data *dd)
 	/* Enable the block device and add it to /dev */
 	device_add_disk(&dd->pdev->dev, dd->disk, NULL);
 
-	dd->bdev = bdget_disk(dd->disk, 0);
 	/*
 	 * Now that the disk is active, initialize any sysfs attributes
 	 * managed by the protocol layer.
@@ -3721,9 +3720,6 @@ static int mtip_block_initialize(struct driver_data *dd)
 	return rv;
 
 kthread_run_error:
-	bdput(dd->bdev);
-	dd->bdev = NULL;
-
 	/* Delete our gendisk. This also removes the device from /dev */
 	del_gendisk(dd->disk);
 
@@ -3804,14 +3800,6 @@ static int mtip_block_remove(struct driver_data *dd)
 	blk_mq_tagset_busy_iter(&dd->tags, mtip_no_dev_cleanup, dd);
 	blk_mq_unquiesce_queue(dd->queue);
 
-	/*
-	 * Delete our gendisk structure. This also removes the device
-	 * from /dev
-	 */
-	if (dd->bdev) {
-		bdput(dd->bdev);
-		dd->bdev = NULL;
-	}
 	if (dd->disk) {
 		if (test_bit(MTIP_DDF_INIT_DONE_BIT, &dd->dd_flag))
 			del_gendisk(dd->disk);
@@ -4206,9 +4194,6 @@ static void mtip_pci_remove(struct pci_dev *pdev)
 	} while (atomic_read(&dd->irq_workers_active) != 0 &&
 		time_before(jiffies, to));
 
-	if (!dd->sr)
-		fsync_bdev(dd->bdev);
-
 	if (atomic_read(&dd->irq_workers_active) != 0) {
 		dev_warn(&dd->pdev->dev,
 			"Completion workers still active!\n");
diff --git a/drivers/block/mtip32xx/mtip32xx.h b/drivers/block/mtip32xx/mtip32xx.h
index e22a7f0523bf30..88f4206310e4c8 100644
--- a/drivers/block/mtip32xx/mtip32xx.h
+++ b/drivers/block/mtip32xx/mtip32xx.h
@@ -463,8 +463,6 @@ struct driver_data {
 
 	int isr_binding;
 
-	struct block_device *bdev;
-
 	struct list_head online_list; /* linkage for online list */
 
 	struct list_head remove_list; /* linkage for removing list */
-- 
2.29.2

--
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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 06/45] zram: remove the claim mechanism
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (4 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 05/45] mtip32xx: remove the call to fsync_bdev on removal Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-25 12:37   ` Jan Kara
  2020-11-24 13:27 ` [dm-devel] [PATCH 07/45] zram: do not call set_blocksize Christoph Hellwig
                   ` (38 subsequent siblings)
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

The zram claim mechanism was added to ensure no new opens come in
during teardown.  But the proper way to archive that is to call
del_gendisk first, which takes care of all that.  Once del_gendisk
is called in the right place, the reset side can also be simplified
as no I/O can be outstanding on a block device that is not open.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/block/zram/zram_drv.c | 72 ++++++++---------------------------
 1 file changed, 15 insertions(+), 57 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 6d15d51cee2b7e..2e6d75ec1afddb 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1756,64 +1756,33 @@ static ssize_t disksize_store(struct device *dev,
 static ssize_t reset_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t len)
 {
-	int ret;
-	unsigned short do_reset;
-	struct zram *zram;
+	struct zram *zram = dev_to_zram(dev);
 	struct block_device *bdev;
+	unsigned short do_reset;
+	int ret = 0;
 
 	ret = kstrtou16(buf, 10, &do_reset);
 	if (ret)
 		return ret;
-
 	if (!do_reset)
 		return -EINVAL;
 
-	zram = dev_to_zram(dev);
 	bdev = bdget_disk(zram->disk, 0);
 	if (!bdev)
 		return -ENOMEM;
 
 	mutex_lock(&bdev->bd_mutex);
-	/* Do not reset an active device or claimed device */
-	if (bdev->bd_openers || zram->claim) {
-		mutex_unlock(&bdev->bd_mutex);
-		bdput(bdev);
-		return -EBUSY;
-	}
-
-	/* From now on, anyone can't open /dev/zram[0-9] */
-	zram->claim = true;
+	if (bdev->bd_openers)
+		ret = -EBUSY;
+	else
+		zram_reset_device(zram);
 	mutex_unlock(&bdev->bd_mutex);
-
-	/* Make sure all the pending I/O are finished */
-	fsync_bdev(bdev);
-	zram_reset_device(zram);
 	bdput(bdev);
 
-	mutex_lock(&bdev->bd_mutex);
-	zram->claim = false;
-	mutex_unlock(&bdev->bd_mutex);
-
-	return len;
-}
-
-static int zram_open(struct block_device *bdev, fmode_t mode)
-{
-	int ret = 0;
-	struct zram *zram;
-
-	WARN_ON(!mutex_is_locked(&bdev->bd_mutex));
-
-	zram = bdev->bd_disk->private_data;
-	/* zram was claimed to reset so open request fails */
-	if (zram->claim)
-		ret = -EBUSY;
-
-	return ret;
+	return ret ? ret : len;
 }
 
 static const struct block_device_operations zram_devops = {
-	.open = zram_open,
 	.submit_bio = zram_submit_bio,
 	.swap_slot_free_notify = zram_slot_free_notify,
 	.rw_page = zram_rw_page,
@@ -1821,7 +1790,6 @@ static const struct block_device_operations zram_devops = {
 };
 
 static const struct block_device_operations zram_wb_devops = {
-	.open = zram_open,
 	.submit_bio = zram_submit_bio,
 	.swap_slot_free_notify = zram_slot_free_notify,
 	.owner = THIS_MODULE
@@ -1974,32 +1942,22 @@ static int zram_add(void)
 
 static int zram_remove(struct zram *zram)
 {
-	struct block_device *bdev;
-
-	bdev = bdget_disk(zram->disk, 0);
-	if (!bdev)
-		return -ENOMEM;
+	struct block_device *bdev = bdget_disk(zram->disk, 0);
 
-	mutex_lock(&bdev->bd_mutex);
-	if (bdev->bd_openers || zram->claim) {
-		mutex_unlock(&bdev->bd_mutex);
+	if (bdev) {
+		if (bdev->bd_openers) {
+			bdput(bdev);
+			return -EBUSY;
+		}
 		bdput(bdev);
-		return -EBUSY;
 	}
 
-	zram->claim = true;
-	mutex_unlock(&bdev->bd_mutex);
-
+	del_gendisk(zram->disk);
 	zram_debugfs_unregister(zram);
-
-	/* Make sure all the pending I/O are finished */
-	fsync_bdev(bdev);
 	zram_reset_device(zram);
-	bdput(bdev);
 
 	pr_info("Removed device: %s\n", zram->disk->disk_name);
 
-	del_gendisk(zram->disk);
 	blk_cleanup_queue(zram->disk->queue);
 	put_disk(zram->disk);
 	kfree(zram);
-- 
2.29.2

--
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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 07/45] zram: do not call set_blocksize
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (5 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 06/45] zram: remove the claim mechanism Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 13:27 ` [dm-devel] [PATCH 08/45] loop: " Christoph Hellwig
                   ` (37 subsequent siblings)
  44 siblings, 0 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

set_blocksize is used by file systems to use their preferred buffer cache
block size.  Block drivers should not set it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/block/zram/zram_drv.c | 11 +----------
 drivers/block/zram/zram_drv.h |  1 -
 2 files changed, 1 insertion(+), 11 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 2e6d75ec1afddb..88baa6158eaee1 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -403,13 +403,10 @@ static void reset_bdev(struct zram *zram)
 		return;
 
 	bdev = zram->bdev;
-	if (zram->old_block_size)
-		set_blocksize(bdev, zram->old_block_size);
 	blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
 	/* hope filp_close flush all of IO */
 	filp_close(zram->backing_dev, NULL);
 	zram->backing_dev = NULL;
-	zram->old_block_size = 0;
 	zram->bdev = NULL;
 	zram->disk->fops = &zram_devops;
 	kvfree(zram->bitmap);
@@ -454,7 +451,7 @@ static ssize_t backing_dev_store(struct device *dev,
 	struct file *backing_dev = NULL;
 	struct inode *inode;
 	struct address_space *mapping;
-	unsigned int bitmap_sz, old_block_size = 0;
+	unsigned int bitmap_sz;
 	unsigned long nr_pages, *bitmap = NULL;
 	struct block_device *bdev = NULL;
 	int err;
@@ -509,14 +506,8 @@ static ssize_t backing_dev_store(struct device *dev,
 		goto out;
 	}
 
-	old_block_size = block_size(bdev);
-	err = set_blocksize(bdev, PAGE_SIZE);
-	if (err)
-		goto out;
-
 	reset_bdev(zram);
 
-	zram->old_block_size = old_block_size;
 	zram->bdev = bdev;
 	zram->backing_dev = backing_dev;
 	zram->bitmap = bitmap;
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index f2fd46daa76045..712354a4207c77 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -118,7 +118,6 @@ struct zram {
 	bool wb_limit_enable;
 	u64 bd_wb_limit;
 	struct block_device *bdev;
-	unsigned int old_block_size;
 	unsigned long *bitmap;
 	unsigned long nr_pages;
 #endif
-- 
2.29.2

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 08/45] loop: do not call set_blocksize
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (6 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 07/45] zram: do not call set_blocksize Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-25 13:37   ` Jan Kara
  2020-11-24 13:27 ` [dm-devel] [PATCH 09/45] dm: simplify flush_bio initialization in __send_empty_flush Christoph Hellwig
                   ` (36 subsequent siblings)
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

set_blocksize is used by file systems to use their preferred buffer cache
block size.  Block drivers should not set it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/block/loop.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 9a27d4f1c08aac..b42c728620c9e4 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1164,9 +1164,6 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
 	size = get_loop_size(lo, file);
 	loop_set_size(lo, size);
 
-	set_blocksize(bdev, S_ISBLK(inode->i_mode) ?
-		      block_size(inode->i_bdev) : PAGE_SIZE);
-
 	lo->lo_state = Lo_bound;
 	if (part_shift)
 		lo->lo_flags |= LO_FLAGS_PARTSCAN;
-- 
2.29.2

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 09/45] dm: simplify flush_bio initialization in __send_empty_flush
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (7 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 08/45] loop: " Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 13:27 ` [dm-devel] [PATCH 10/45] dm: remove the block_device reference in struct mapped_device Christoph Hellwig
                   ` (35 subsequent siblings)
  44 siblings, 0 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

We don't really need the struct block_device to initialize a bio.  So
switch from using bio_set_dev to manually setting up bi_disk (bi_partno
will always be zero and has been cleared by bio_init already).

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
---
 drivers/md/dm.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 50541d336c719b..ab0a8335f098d9 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1422,18 +1422,12 @@ static int __send_empty_flush(struct clone_info *ci)
 	 */
 	bio_init(&flush_bio, NULL, 0);
 	flush_bio.bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC;
+	flush_bio.bi_disk = ci->io->md->disk;
+	bio_associate_blkg(&flush_bio);
+
 	ci->bio = &flush_bio;
 	ci->sector_count = 0;
 
-	/*
-	 * Empty flush uses a statically initialized bio, as the base for
-	 * cloning.  However, blkg association requires that a bdev is
-	 * associated with a gendisk, which doesn't happen until the bdev is
-	 * opened.  So, blkg association is done at issue time of the flush
-	 * rather than when the device is created in alloc_dev().
-	 */
-	bio_set_dev(ci->bio, ci->io->md->bdev);
-
 	BUG_ON(bio_has_data(ci->bio));
 	while ((ti = dm_table_get_target(ci->map, target_nr++)))
 		__send_duplicate_bios(ci, ti, ti->num_flush_bios, NULL);
-- 
2.29.2

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 10/45] dm: remove the block_device reference in struct mapped_device
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (8 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 09/45] dm: simplify flush_bio initialization in __send_empty_flush Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 13:27 ` [dm-devel] [PATCH 11/45] block: remove a duplicate __disk_get_part prototype Christoph Hellwig
                   ` (34 subsequent siblings)
  44 siblings, 0 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Get rid of the long-lasting struct block_device reference in
struct mapped_device.  The only remaining user is the freeze code,
where we can trivially look up the block device at freeze time
and release the reference at thaw time.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
---
 drivers/md/dm-core.h |  2 --
 drivers/md/dm.c      | 25 ++++++++++++++-----------
 2 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h
index aace147effcacb..086d293c2b036c 100644
--- a/drivers/md/dm-core.h
+++ b/drivers/md/dm-core.h
@@ -102,8 +102,6 @@ struct mapped_device {
 	/* kobject and completion */
 	struct dm_kobject_holder kobj_holder;
 
-	struct block_device *bdev;
-
 	struct dm_stats stats;
 
 	/* for blk-mq request-based DM support */
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index ab0a8335f098d9..48051db006f30c 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1744,11 +1744,6 @@ static void cleanup_mapped_device(struct mapped_device *md)
 
 	cleanup_srcu_struct(&md->io_barrier);
 
-	if (md->bdev) {
-		bdput(md->bdev);
-		md->bdev = NULL;
-	}
-
 	mutex_destroy(&md->suspend_lock);
 	mutex_destroy(&md->type_lock);
 	mutex_destroy(&md->table_devices_lock);
@@ -1840,10 +1835,6 @@ static struct mapped_device *alloc_dev(int minor)
 	if (!md->wq)
 		goto bad;
 
-	md->bdev = bdget_disk(md->disk, 0);
-	if (!md->bdev)
-		goto bad;
-
 	dm_stats_init(&md->stats);
 
 	/* Populate the mapping, nobody knows we exist yet */
@@ -2384,11 +2375,16 @@ struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
  */
 static int lock_fs(struct mapped_device *md)
 {
+	struct block_device *bdev;
 	int r;
 
 	WARN_ON(test_bit(DMF_FROZEN, &md->flags));
 
-	r = freeze_bdev(md->bdev);
+	bdev = bdget_disk(md->disk, 0);
+	if (!bdev)
+		return -ENOMEM;
+	r = freeze_bdev(bdev);
+	bdput(bdev);
 	if (!r)
 		set_bit(DMF_FROZEN, &md->flags);
 	return r;
@@ -2396,9 +2392,16 @@ static int lock_fs(struct mapped_device *md)
 
 static void unlock_fs(struct mapped_device *md)
 {
+	struct block_device *bdev;
+
 	if (!test_bit(DMF_FROZEN, &md->flags))
 		return;
-	thaw_bdev(md->bdev);
+
+	bdev = bdget_disk(md->disk, 0);
+	if (!bdev)
+		return;
+	thaw_bdev(bdev);
+	bdput(bdev);
 	clear_bit(DMF_FROZEN, &md->flags);
 }
 
-- 
2.29.2

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 11/45] block: remove a duplicate __disk_get_part prototype
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (9 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 10/45] dm: remove the block_device reference in struct mapped_device Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 17:36   ` Tejun Heo
  2020-11-24 13:27 ` [dm-devel] [PATCH 12/45] block: remove a superflous check in blkpg_do_ioctl Christoph Hellwig
                   ` (33 subsequent siblings)
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 include/linux/genhd.h | 1 -
 1 file changed, 1 deletion(-)

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 46553d6d602563..22f5b9fd96f8bf 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -250,7 +250,6 @@ static inline dev_t part_devt(struct hd_struct *part)
 	return part_to_dev(part)->devt;
 }
 
-extern struct hd_struct *__disk_get_part(struct gendisk *disk, int partno);
 extern struct hd_struct *disk_get_part(struct gendisk *disk, int partno);
 
 static inline void disk_put_part(struct hd_struct *part)
-- 
2.29.2

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 12/45] block: remove a superflous check in blkpg_do_ioctl
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (10 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 11/45] block: remove a duplicate __disk_get_part prototype Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 17:37   ` Tejun Heo
  2020-11-25 13:39   ` Jan Kara
  2020-11-24 13:27 ` [dm-devel] [PATCH 13/45] block: add a bdev_kobj helper Christoph Hellwig
                   ` (32 subsequent siblings)
  44 siblings, 2 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

sector_t is now always a u64, so this check is not needed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/ioctl.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/block/ioctl.c b/block/ioctl.c
index 6b785181344fe1..0c09bb7a6ff35f 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -35,15 +35,6 @@ static int blkpg_do_ioctl(struct block_device *bdev,
 	start = p.start >> SECTOR_SHIFT;
 	length = p.length >> SECTOR_SHIFT;
 
-	/* check for fit in a hd_struct */
-	if (sizeof(sector_t) < sizeof(long long)) {
-		long pstart = start, plength = length;
-
-		if (pstart != start || plength != length || pstart < 0 ||
-		    plength < 0 || p.pno > 65535)
-			return -EINVAL;
-	}
-
 	switch (op) {
 	case BLKPG_ADD_PARTITION:
 		/* check if partition is aligned to blocksize */
-- 
2.29.2

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 13/45] block: add a bdev_kobj helper
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (11 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 12/45] block: remove a superflous check in blkpg_do_ioctl Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 13:41   ` Coly Li
  2020-11-24 17:37   ` Tejun Heo
  2020-11-24 13:27 ` [dm-devel] [PATCH 14/45] block: use disk_part_iter_exit in disk_part_iter_next Christoph Hellwig
                   ` (31 subsequent siblings)
  44 siblings, 2 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Add a little helper to find the kobject for a struct block_device.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 drivers/md/bcache/super.c |  7 ++-----
 drivers/md/md.c           |  4 +---
 fs/block_dev.c            |  6 +++---
 fs/btrfs/sysfs.c          | 15 +++------------
 include/linux/blk_types.h |  3 +++
 5 files changed, 12 insertions(+), 23 deletions(-)

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 46a00134a36ae1..a6a5e21e4fd136 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1447,8 +1447,7 @@ static int register_bdev(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
 		goto err;
 
 	err = "error creating kobject";
-	if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj,
-			"bcache"))
+	if (kobject_add(&dc->disk.kobj, bdev_kobj(bdev), "bcache"))
 		goto err;
 	if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj))
 		goto err;
@@ -2342,9 +2341,7 @@ static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
 		goto err;
 	}
 
-	if (kobject_add(&ca->kobj,
-			&part_to_dev(bdev->bd_part)->kobj,
-			"bcache")) {
+	if (kobject_add(&ca->kobj, bdev_kobj(bdev), "bcache")) {
 		err = "error calling kobject_add";
 		ret = -ENOMEM;
 		goto out;
diff --git a/drivers/md/md.c b/drivers/md/md.c
index b2edf5e0f965b5..7ce6047c856ea2 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2414,7 +2414,6 @@ EXPORT_SYMBOL(md_integrity_add_rdev);
 static int bind_rdev_to_array(struct md_rdev *rdev, struct mddev *mddev)
 {
 	char b[BDEVNAME_SIZE];
-	struct kobject *ko;
 	int err;
 
 	/* prevent duplicates */
@@ -2477,9 +2476,8 @@ static int bind_rdev_to_array(struct md_rdev *rdev, struct mddev *mddev)
 	if ((err = kobject_add(&rdev->kobj, &mddev->kobj, "dev-%s", b)))
 		goto fail;
 
-	ko = &part_to_dev(rdev->bdev->bd_part)->kobj;
 	/* failure here is OK */
-	err = sysfs_create_link(&rdev->kobj, ko, "block");
+	err = sysfs_create_link(&rdev->kobj, bdev_kobj(rdev->bdev), "block");
 	rdev->sysfs_state = sysfs_get_dirent_safe(rdev->kobj.sd, "state");
 	rdev->sysfs_unack_badblocks =
 		sysfs_get_dirent_safe(rdev->kobj.sd, "unacknowledged_bad_blocks");
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 60492620d51866..f6a2a06ad262fa 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1242,7 +1242,7 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
 	holder->disk = disk;
 	holder->refcnt = 1;
 
-	ret = add_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
+	ret = add_symlink(disk->slave_dir, bdev_kobj(bdev));
 	if (ret)
 		goto out_free;
 
@@ -1259,7 +1259,7 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
 	goto out_unlock;
 
 out_del:
-	del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
+	del_symlink(disk->slave_dir, bdev_kobj(bdev));
 out_free:
 	kfree(holder);
 out_unlock:
@@ -1287,7 +1287,7 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
 	holder = bd_find_holder_disk(bdev, disk);
 
 	if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) {
-		del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
+		del_symlink(disk->slave_dir, bdev_kobj(bdev));
 		del_symlink(bdev->bd_part->holder_dir,
 			    &disk_to_dev(disk)->kobj);
 		kobject_put(bdev->bd_part->holder_dir);
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 279d9262b676d4..24b6c6dc69000a 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -1232,8 +1232,6 @@ int btrfs_sysfs_add_space_info_type(struct btrfs_fs_info *fs_info,
 
 void btrfs_sysfs_remove_device(struct btrfs_device *device)
 {
-	struct hd_struct *disk;
-	struct kobject *disk_kobj;
 	struct kobject *devices_kobj;
 
 	/*
@@ -1243,11 +1241,8 @@ void btrfs_sysfs_remove_device(struct btrfs_device *device)
 	devices_kobj = device->fs_info->fs_devices->devices_kobj;
 	ASSERT(devices_kobj);
 
-	if (device->bdev) {
-		disk = device->bdev->bd_part;
-		disk_kobj = &part_to_dev(disk)->kobj;
-		sysfs_remove_link(devices_kobj, disk_kobj->name);
-	}
+	if (device->bdev)
+		sysfs_remove_link(devices_kobj, bdev_kobj(device->bdev)->name);
 
 	if (device->devid_kobj.state_initialized) {
 		kobject_del(&device->devid_kobj);
@@ -1353,11 +1348,7 @@ int btrfs_sysfs_add_device(struct btrfs_device *device)
 	nofs_flag = memalloc_nofs_save();
 
 	if (device->bdev) {
-		struct hd_struct *disk;
-		struct kobject *disk_kobj;
-
-		disk = device->bdev->bd_part;
-		disk_kobj = &part_to_dev(disk)->kobj;
+		struct kobject *disk_kobj = bdev_kobj(device->bdev);
 
 		ret = sysfs_create_link(devices_kobj, disk_kobj, disk_kobj->name);
 		if (ret) {
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index ebfb4e7c1fd125..9698f459cc65c9 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -49,6 +49,9 @@ struct block_device {
 	struct super_block	*bd_fsfreeze_sb;
 } __randomize_layout;
 
+#define bdev_kobj(_bdev) \
+	(&part_to_dev((_bdev)->bd_part)->kobj)
+
 /*
  * Block error status values.  See block/blk-core:blk_errors for the details.
  * Alpha cannot write a byte atomically, so we need to use 32-bit value.
-- 
2.29.2

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 14/45] block: use disk_part_iter_exit in disk_part_iter_next
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (12 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 13/45] block: add a bdev_kobj helper Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 17:37   ` Tejun Heo
  2020-11-24 13:27 ` [dm-devel] [PATCH 15/45] block: use put_device in put_disk Christoph Hellwig
                   ` (30 subsequent siblings)
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Call disk_part_iter_exit in disk_part_iter_next instead of duplicating
the functionality.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 block/genhd.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 4e039524f92b8f..0bd9c41dd4cb69 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -227,8 +227,7 @@ struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter)
 	int inc, end;
 
 	/* put the last partition */
-	disk_put_part(piter->part);
-	piter->part = NULL;
+	disk_part_iter_exit(piter);
 
 	/* get part_tbl */
 	rcu_read_lock();
-- 
2.29.2

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 15/45] block: use put_device in put_disk
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (13 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 14/45] block: use disk_part_iter_exit in disk_part_iter_next Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 17:37   ` Tejun Heo
  2020-11-24 13:27 ` [dm-devel] [PATCH 16/45] block: change the hash used for looking up block devices Christoph Hellwig
                   ` (29 subsequent siblings)
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Use put_device to put the device instead of poking into the internals
and using kobject_put.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 block/genhd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/genhd.c b/block/genhd.c
index 0bd9c41dd4cb69..f46e89226fdf91 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1803,7 +1803,7 @@ EXPORT_SYMBOL(__alloc_disk_node);
 void put_disk(struct gendisk *disk)
 {
 	if (disk)
-		kobject_put(&disk_to_dev(disk)->kobj);
+		put_device(disk_to_dev(disk));
 }
 EXPORT_SYMBOL(put_disk);
 
-- 
2.29.2

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 16/45] block: change the hash used for looking up block devices
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (14 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 15/45] block: use put_device in put_disk Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 17:38   ` Tejun Heo
  2020-11-24 13:27 ` [dm-devel] [PATCH 17/45] init: refactor name_to_dev_t Christoph Hellwig
                   ` (28 subsequent siblings)
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Adding the minor to the major creates tons of pointless conflicts. Just
use the dev_t itself, which is 32-bits and thus is guaranteed to fit
into ino_t.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/block_dev.c | 26 ++------------------------
 1 file changed, 2 insertions(+), 24 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index f6a2a06ad262fa..437f67e12b2838 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -863,35 +863,12 @@ void __init bdev_cache_init(void)
 	blockdev_superblock = bd_mnt->mnt_sb;   /* For writeback */
 }
 
-/*
- * Most likely _very_ bad one - but then it's hardly critical for small
- * /dev and can be fixed when somebody will need really large one.
- * Keep in mind that it will be fed through icache hash function too.
- */
-static inline unsigned long hash(dev_t dev)
-{
-	return MAJOR(dev)+MINOR(dev);
-}
-
-static int bdev_test(struct inode *inode, void *data)
-{
-	return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data;
-}
-
-static int bdev_set(struct inode *inode, void *data)
-{
-	BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data;
-	return 0;
-}
-
 static struct block_device *bdget(dev_t dev)
 {
 	struct block_device *bdev;
 	struct inode *inode;
 
-	inode = iget5_locked(blockdev_superblock, hash(dev),
-			bdev_test, bdev_set, &dev);
-
+	inode = iget_locked(blockdev_superblock, dev);
 	if (!inode)
 		return NULL;
 
@@ -903,6 +880,7 @@ static struct block_device *bdget(dev_t dev)
 		bdev->bd_super = NULL;
 		bdev->bd_inode = inode;
 		bdev->bd_part_count = 0;
+		bdev->bd_dev = dev;
 		inode->i_mode = S_IFBLK;
 		inode->i_rdev = dev;
 		inode->i_bdev = bdev;
-- 
2.29.2

--
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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 17/45] init: refactor name_to_dev_t
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (15 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 16/45] block: change the hash used for looking up block devices Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 17:38   ` Tejun Heo
  2020-11-24 13:27 ` [dm-devel] [PATCH 18/45] init: refactor devt_from_partuuid Christoph Hellwig
                   ` (27 subsequent siblings)
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Split each case into a self-contained helper, and move the block
dependent code entirely under the pre-existing #ifdef CONFIG_BLOCK.
This allows to remove the blk_lookup_devt stub in genhd.h.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 include/linux/genhd.h |   7 +-
 init/do_mounts.c      | 183 +++++++++++++++++++++---------------------
 2 files changed, 91 insertions(+), 99 deletions(-)

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 22f5b9fd96f8bf..ca5e356084c353 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -388,18 +388,13 @@ static inline void bd_unlink_disk_holder(struct block_device *bdev,
 }
 #endif /* CONFIG_SYSFS */
 
+dev_t blk_lookup_devt(const char *name, int partno);
 #ifdef CONFIG_BLOCK
 void printk_all_partitions(void);
-dev_t blk_lookup_devt(const char *name, int partno);
 #else /* CONFIG_BLOCK */
 static inline void printk_all_partitions(void)
 {
 }
-static inline dev_t blk_lookup_devt(const char *name, int partno)
-{
-	dev_t devt = MKDEV(0, 0);
-	return devt;
-}
 #endif /* CONFIG_BLOCK */
 
 #endif /* _LINUX_GENHD_H */
diff --git a/init/do_mounts.c b/init/do_mounts.c
index b5f9604d0c98a2..aef2f24461c7f1 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -90,7 +90,6 @@ static int match_dev_by_uuid(struct device *dev, const void *data)
 	return 0;
 }
 
-
 /**
  * devt_from_partuuid - looks up the dev_t of a partition by its UUID
  * @uuid_str:	char array containing ascii UUID
@@ -186,7 +185,83 @@ static int match_dev_by_label(struct device *dev, const void *data)
 
 	return 0;
 }
-#endif
+
+static dev_t devt_from_partlabel(const char *label)
+{
+	struct device *dev;
+	dev_t devt = 0;
+
+	dev = class_find_device(&block_class, NULL, label, &match_dev_by_label);
+	if (dev) {
+		devt = dev->devt;
+		put_device(dev);
+	}
+
+	return devt;
+}
+
+static dev_t devt_from_devname(const char *name)
+{
+	dev_t devt = 0;
+	int part;
+	char s[32];
+	char *p;
+
+	if (strlen(name) > 31)
+		return 0;
+	strcpy(s, name);
+	for (p = s; *p; p++) {
+		if (*p == '/')
+			*p = '!';
+	}
+
+	devt = blk_lookup_devt(s, 0);
+	if (devt)
+		return devt;
+
+	/*
+	 * Try non-existent, but valid partition, which may only exist after
+	 * opening the device, like partitioned md devices.
+	 */
+	while (p > s && isdigit(p[-1]))
+		p--;
+	if (p == s || !*p || *p == '0')
+		return 0;
+
+	/* try disk name without <part number> */
+	part = simple_strtoul(p, NULL, 10);
+	*p = '\0';
+	devt = blk_lookup_devt(s, part);
+	if (devt)
+		return devt;
+
+	/* try disk name without p<part number> */
+	if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
+		return 0;
+	p[-1] = '\0';
+	return blk_lookup_devt(s, part);
+}
+#endif /* CONFIG_BLOCK */
+
+static dev_t devt_from_devnum(const char *name)
+{
+	unsigned maj, min, offset;
+	dev_t devt = 0;
+	char *p, dummy;
+
+	if (sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2 ||
+	    sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3) {
+		devt = MKDEV(maj, min);
+		if (maj != MAJOR(devt) || min != MINOR(devt))
+			return 0;
+	} else {
+		devt = new_decode_dev(simple_strtoul(name, &p, 16));
+		if (*p)
+			return 0;
+	}
+
+	return devt;
+}
 
 /*
  *	Convert a name into device number.  We accept the following variants:
@@ -218,101 +293,23 @@ static int match_dev_by_label(struct device *dev, const void *data)
  *	name contains slashes, the device name has them replaced with
  *	bangs.
  */
-
 dev_t name_to_dev_t(const char *name)
 {
-	char s[32];
-	char *p;
-	dev_t res = 0;
-	int part;
-
+	if (strcmp(name, "/dev/nfs") == 0)
+		return Root_NFS;
+	if (strcmp(name, "/dev/cifs") == 0)
+		return Root_CIFS;
+	if (strcmp(name, "/dev/ram") == 0)
+		return Root_RAM0;
 #ifdef CONFIG_BLOCK
-	if (strncmp(name, "PARTUUID=", 9) == 0) {
-		name += 9;
-		res = devt_from_partuuid(name);
-		if (!res)
-			goto fail;
-		goto done;
-	} else if (strncmp(name, "PARTLABEL=", 10) == 0) {
-		struct device *dev;
-
-		dev = class_find_device(&block_class, NULL, name + 10,
-					&match_dev_by_label);
-		if (!dev)
-			goto fail;
-
-		res = dev->devt;
-		put_device(dev);
-		goto done;
-	}
+	if (strncmp(name, "PARTUUID=", 9) == 0)
+		return devt_from_partuuid(name + 9);
+	if (strncmp(name, "PARTLABEL=", 10) == 0)
+		return devt_from_partlabel(name + 10);
+	if (strncmp(name, "/dev/", 5) == 0)
+		return devt_from_devname(name + 5);
 #endif
-
-	if (strncmp(name, "/dev/", 5) != 0) {
-		unsigned maj, min, offset;
-		char dummy;
-
-		if ((sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2) ||
-		    (sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3)) {
-			res = MKDEV(maj, min);
-			if (maj != MAJOR(res) || min != MINOR(res))
-				goto fail;
-		} else {
-			res = new_decode_dev(simple_strtoul(name, &p, 16));
-			if (*p)
-				goto fail;
-		}
-		goto done;
-	}
-
-	name += 5;
-	res = Root_NFS;
-	if (strcmp(name, "nfs") == 0)
-		goto done;
-	res = Root_CIFS;
-	if (strcmp(name, "cifs") == 0)
-		goto done;
-	res = Root_RAM0;
-	if (strcmp(name, "ram") == 0)
-		goto done;
-
-	if (strlen(name) > 31)
-		goto fail;
-	strcpy(s, name);
-	for (p = s; *p; p++)
-		if (*p == '/')
-			*p = '!';
-	res = blk_lookup_devt(s, 0);
-	if (res)
-		goto done;
-
-	/*
-	 * try non-existent, but valid partition, which may only exist
-	 * after revalidating the disk, like partitioned md devices
-	 */
-	while (p > s && isdigit(p[-1]))
-		p--;
-	if (p == s || !*p || *p == '0')
-		goto fail;
-
-	/* try disk name without <part number> */
-	part = simple_strtoul(p, NULL, 10);
-	*p = '\0';
-	res = blk_lookup_devt(s, part);
-	if (res)
-		goto done;
-
-	/* try disk name without p<part number> */
-	if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
-		goto fail;
-	p[-1] = '\0';
-	res = blk_lookup_devt(s, part);
-	if (res)
-		goto done;
-
-fail:
-	return 0;
-done:
-	return res;
+	return devt_from_devnum(name);
 }
 EXPORT_SYMBOL_GPL(name_to_dev_t);
 
-- 
2.29.2

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 18/45] init: refactor devt_from_partuuid
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (16 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 17/45] init: refactor name_to_dev_t Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 17:38   ` Tejun Heo
  2020-11-24 13:27 ` [dm-devel] [PATCH 19/45] init: cleanup match_dev_by_uuid and match_dev_by_label Christoph Hellwig
                   ` (26 subsequent siblings)
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

The code in devt_from_partuuid is very convoluted.  Refactor a bit by
sanitizing the goto and variable name usage.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 init/do_mounts.c | 68 ++++++++++++++++++++++--------------------------
 1 file changed, 31 insertions(+), 37 deletions(-)

diff --git a/init/do_mounts.c b/init/do_mounts.c
index aef2f24461c7f1..afa26a4028d25e 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -105,13 +105,10 @@ static int match_dev_by_uuid(struct device *dev, const void *data)
  */
 static dev_t devt_from_partuuid(const char *uuid_str)
 {
-	dev_t res = 0;
 	struct uuidcmp cmp;
 	struct device *dev = NULL;
-	struct gendisk *disk;
-	struct hd_struct *part;
+	dev_t devt = 0;
 	int offset = 0;
-	bool clear_root_wait = false;
 	char *slash;
 
 	cmp.uuid = uuid_str;
@@ -120,52 +117,49 @@ static dev_t devt_from_partuuid(const char *uuid_str)
 	/* Check for optional partition number offset attributes. */
 	if (slash) {
 		char c = 0;
+
 		/* Explicitly fail on poor PARTUUID syntax. */
-		if (sscanf(slash + 1,
-			   "PARTNROFF=%d%c", &offset, &c) != 1) {
-			clear_root_wait = true;
-			goto done;
-		}
+		if (sscanf(slash + 1, "PARTNROFF=%d%c", &offset, &c) != 1)
+			goto clear_root_wait;
 		cmp.len = slash - uuid_str;
 	} else {
 		cmp.len = strlen(uuid_str);
 	}
 
-	if (!cmp.len) {
-		clear_root_wait = true;
-		goto done;
-	}
+	if (!cmp.len)
+		goto clear_root_wait;
 
-	dev = class_find_device(&block_class, NULL, &cmp,
-				&match_dev_by_uuid);
+	dev = class_find_device(&block_class, NULL, &cmp, &match_dev_by_uuid);
 	if (!dev)
-		goto done;
-
-	res = dev->devt;
+		return 0;
 
-	/* Attempt to find the partition by offset. */
-	if (!offset)
-		goto no_offset;
+	if (offset) {
+		/*
+		 * Attempt to find the requested partition by adding an offset
+		 * to the partition number found by UUID.
+		 */
+		struct hd_struct *part;
 
-	res = 0;
-	disk = part_to_disk(dev_to_part(dev));
-	part = disk_get_part(disk, dev_to_part(dev)->partno + offset);
-	if (part) {
-		res = part_devt(part);
-		put_device(part_to_dev(part));
+		part = disk_get_part(dev_to_disk(dev),
+				     dev_to_part(dev)->partno + offset);
+		if (part) {
+			devt = part_devt(part);
+			put_device(part_to_dev(part));
+		}
+	} else {
+		devt = dev->devt;
 	}
 
-no_offset:
 	put_device(dev);
-done:
-	if (clear_root_wait) {
-		pr_err("VFS: PARTUUID= is invalid.\n"
-		       "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
-		if (root_wait)
-			pr_err("Disabling rootwait; root= is invalid.\n");
-		root_wait = 0;
-	}
-	return res;
+	return devt;
+
+clear_root_wait:
+	pr_err("VFS: PARTUUID= is invalid.\n"
+	       "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
+	if (root_wait)
+		pr_err("Disabling rootwait; root= is invalid.\n");
+	root_wait = 0;
+	return 0;
 }
 
 /**
-- 
2.29.2

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 19/45] init: cleanup match_dev_by_uuid and match_dev_by_label
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (17 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 18/45] init: refactor devt_from_partuuid Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 17:39   ` Tejun Heo
  2020-11-24 13:27 ` [dm-devel] [PATCH 20/45] block: refactor __blkdev_put Christoph Hellwig
                   ` (25 subsequent siblings)
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Avoid a totally pointless goto label, and use the same style of
comparism for both helpers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 init/do_mounts.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/init/do_mounts.c b/init/do_mounts.c
index afa26a4028d25e..5879edf083b318 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -79,15 +79,10 @@ static int match_dev_by_uuid(struct device *dev, const void *data)
 	const struct uuidcmp *cmp = data;
 	struct hd_struct *part = dev_to_part(dev);
 
-	if (!part->info)
-		goto no_match;
-
-	if (strncasecmp(cmp->uuid, part->info->uuid, cmp->len))
-		goto no_match;
-
+	if (!part->info ||
+	    strncasecmp(cmp->uuid, part->info->uuid, cmp->len))
+		return 0;
 	return 1;
-no_match:
-	return 0;
 }
 
 /**
@@ -174,10 +169,9 @@ static int match_dev_by_label(struct device *dev, const void *data)
 	const char *label = data;
 	struct hd_struct *part = dev_to_part(dev);
 
-	if (part->info && !strcmp(label, part->info->volname))
-		return 1;
-
-	return 0;
+	if (!part->info || strcmp(label, part->info->volname))
+		return 0;
+	return 1;
 }
 
 static dev_t devt_from_partlabel(const char *label)
-- 
2.29.2

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 20/45] block: refactor __blkdev_put
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (18 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 19/45] init: cleanup match_dev_by_uuid and match_dev_by_label Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 17:41   ` Tejun Heo
  2020-11-24 13:27 ` [dm-devel] [PATCH 21/45] block: refactor blkdev_get Christoph Hellwig
                   ` (24 subsequent siblings)
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Reorder the code to have one big section for the last close, and to use
bdev_is_partition.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/block_dev.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 437f67e12b2838..88847839ef0102 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1738,22 +1738,22 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
 		WARN_ON_ONCE(bdev->bd_holders);
 		sync_blockdev(bdev);
 		kill_bdev(bdev);
-
 		bdev_write_inode(bdev);
-	}
-	if (bdev->bd_contains == bdev) {
-		if (disk->fops->release)
+
+		if (!bdev_is_partition(bdev) && disk->fops->release)
 			disk->fops->release(disk, mode);
-	}
-	if (!bdev->bd_openers) {
+
 		disk_put_part(bdev->bd_part);
 		bdev->bd_part = NULL;
 		bdev->bd_disk = NULL;
-		if (bdev != bdev->bd_contains)
+		if (bdev_is_partition(bdev))
 			victim = bdev->bd_contains;
 		bdev->bd_contains = NULL;
 
 		put_disk_and_module(disk);
+	} else {
+		if (!bdev_is_partition(bdev) && disk->fops->release)
+			disk->fops->release(disk, mode);
 	}
 	mutex_unlock(&bdev->bd_mutex);
 	bdput(bdev);
-- 
2.29.2

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 21/45] block: refactor blkdev_get
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (19 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 20/45] block: refactor __blkdev_put Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 18:03   ` Tejun Heo
  2020-11-24 13:27 ` [dm-devel] [PATCH 22/45] block: opencode devcgroup_inode_permission Christoph Hellwig
                   ` (23 subsequent siblings)
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Move more code that is only run on the outer open but not the open of
the underlying whole device when opening a partition into blkdev_get,
which leads to a much easier to follow structure.

This allows to simplify the disk and module refcounting so that one
reference is held for each open, similar to what we do with normal
file operations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/block_dev.c | 185 +++++++++++++++++++++++--------------------------
 1 file changed, 86 insertions(+), 99 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 88847839ef0102..2ffa11a95f10db 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1403,46 +1403,12 @@ EXPORT_SYMBOL_GPL(bdev_disk_changed);
  *  mutex_lock(part->bd_mutex)
  *    mutex_lock_nested(whole->bd_mutex, 1)
  */
-
-static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
-		int for_part)
+static int __blkdev_get(struct block_device *bdev, struct gendisk *disk,
+		int partno, fmode_t mode)
 {
-	struct block_device *whole = NULL, *claiming = NULL;
-	struct gendisk *disk;
 	int ret;
-	int partno;
-	bool first_open = false, unblock_events = true, need_restart;
-
- restart:
-	need_restart = false;
-	ret = -ENXIO;
-	disk = bdev_get_gendisk(bdev, &partno);
-	if (!disk)
-		goto out;
-
-	if (partno) {
-		whole = bdget_disk(disk, 0);
-		if (!whole) {
-			ret = -ENOMEM;
-			goto out_put_disk;
-		}
-	}
 
-	if (!for_part && (mode & FMODE_EXCL)) {
-		WARN_ON_ONCE(!holder);
-		if (whole)
-			claiming = whole;
-		else
-			claiming = bdev;
-		ret = bd_prepare_to_claim(bdev, claiming, holder);
-		if (ret)
-			goto out_put_whole;
-	}
-
-	disk_block_events(disk);
-	mutex_lock_nested(&bdev->bd_mutex, for_part);
 	if (!bdev->bd_openers) {
-		first_open = true;
 		bdev->bd_disk = disk;
 		bdev->bd_contains = bdev;
 		bdev->bd_partno = partno;
@@ -1454,15 +1420,8 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
 				goto out_clear;
 
 			ret = 0;
-			if (disk->fops->open) {
+			if (disk->fops->open)
 				ret = disk->fops->open(bdev, mode);
-				/*
-				 * If we lost a race with 'disk' being deleted,
-				 * try again.  See md.c
-				 */
-				if (ret == -ERESTARTSYS)
-					need_restart = true;
-			}
 
 			if (!ret) {
 				bd_set_nr_sectors(bdev, get_capacity(disk));
@@ -1482,14 +1441,23 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
 			if (ret)
 				goto out_clear;
 		} else {
-			BUG_ON(for_part);
-			ret = __blkdev_get(whole, mode, NULL, 1);
-			if (ret)
+			struct block_device *whole = bdget_disk(disk, 0);
+
+			mutex_lock_nested(&whole->bd_mutex, 1);
+			ret = __blkdev_get(whole, disk, 0, mode);
+			if (ret) {
+				mutex_unlock(&whole->bd_mutex);
+				bdput(whole);
 				goto out_clear;
-			bdev->bd_contains = bdgrab(whole);
+			}
+			whole->bd_part_count++;
+			mutex_unlock(&whole->bd_mutex);
+
+			bdev->bd_contains = whole;
 			bdev->bd_part = disk_get_part(disk, partno);
 			if (!(disk->flags & GENHD_FL_UP) ||
 			    !bdev->bd_part || !bdev->bd_part->nr_sects) {
+				__blkdev_put(whole, mode, 1);
 				ret = -ENXIO;
 				goto out_clear;
 			}
@@ -1509,58 +1477,17 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
 			    (!ret || ret == -ENOMEDIUM))
 				bdev_disk_changed(bdev, ret == -ENOMEDIUM);
 			if (ret)
-				goto out_unlock_bdev;
+				return ret;
 		}
 	}
 	bdev->bd_openers++;
-	if (for_part)
-		bdev->bd_part_count++;
-	if (claiming)
-		bd_finish_claiming(bdev, claiming, holder);
-
-	/*
-	 * Block event polling for write claims if requested.  Any write holder
-	 * makes the write_holder state stick until all are released.  This is
-	 * good enough and tracking individual writeable reference is too
-	 * fragile given the way @mode is used in blkdev_get/put().
-	 */
-	if (claiming && (mode & FMODE_WRITE) && !bdev->bd_write_holder &&
-	    (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) {
-		bdev->bd_write_holder = true;
-		unblock_events = false;
-	}
-	mutex_unlock(&bdev->bd_mutex);
-
-	if (unblock_events)
-		disk_unblock_events(disk);
-
-	/* only one opener holds refs to the module and disk */
-	if (!first_open)
-		put_disk_and_module(disk);
-	if (whole)
-		bdput(whole);
 	return 0;
 
  out_clear:
 	disk_put_part(bdev->bd_part);
 	bdev->bd_disk = NULL;
 	bdev->bd_part = NULL;
-	if (bdev != bdev->bd_contains)
-		__blkdev_put(bdev->bd_contains, mode, 1);
 	bdev->bd_contains = NULL;
- out_unlock_bdev:
-	if (claiming)
-		bd_abort_claiming(bdev, claiming, holder);
-	mutex_unlock(&bdev->bd_mutex);
-	disk_unblock_events(disk);
- out_put_whole:
- 	if (whole)
-		bdput(whole);
- out_put_disk:
-	put_disk_and_module(disk);
-	if (need_restart)
-		goto restart;
- out:
 	return ret;
 }
 
@@ -1585,7 +1512,12 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
  */
 static int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
 {
-	int ret, perm = 0;
+	struct block_device *claiming;
+	bool unblock_events = true;
+	struct gendisk *disk;
+	int perm = 0;
+	int partno;
+	int ret;
 
 	if (mode & FMODE_READ)
 		perm |= MAY_READ;
@@ -1595,13 +1527,67 @@ static int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
 	if (ret)
 		goto bdput;
 
-	ret =__blkdev_get(bdev, mode, holder, 0);
-	if (ret)
+	/*
+	 * If we lost a race with 'disk' being deleted, try again.  See md.c.
+	 */
+retry:
+	ret = -ENXIO;
+	disk = bdev_get_gendisk(bdev, &partno);
+	if (!disk)
 		goto bdput;
-	return 0;
 
+	if (mode & FMODE_EXCL) {
+		WARN_ON_ONCE(!holder);
+	
+		ret = -ENOMEM;
+		claiming = bdget_disk(disk, 0);
+		if (!claiming)
+			goto put_disk;
+		ret = bd_prepare_to_claim(bdev, claiming, holder);
+		if (ret)
+			goto put_claiming;
+	}
+
+	disk_block_events(disk);
+
+	mutex_lock(&bdev->bd_mutex);
+	ret =__blkdev_get(bdev, disk, partno, mode);
+	if (!(mode & FMODE_EXCL)) {
+		; /* nothing to do here */
+	} else if (ret) {
+		bd_abort_claiming(bdev, claiming, holder);
+	} else {
+		bd_finish_claiming(bdev, claiming, holder);
+
+		/*
+		 * Block event polling for write claims if requested.  Any write
+		 * holder makes the write_holder state stick until all are
+		 * released.  This is good enough and tracking individual
+		 * writeable reference is too fragile given the way @mode is
+		 * used in blkdev_get/put().
+		 */
+		if ((mode & FMODE_WRITE) && !bdev->bd_write_holder &&
+		    (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) {
+			bdev->bd_write_holder = true;
+			unblock_events = false;
+		}
+	}
+	mutex_unlock(&bdev->bd_mutex);
+
+	if (unblock_events)
+		disk_unblock_events(disk);
+
+put_claiming:
+	if (mode & FMODE_EXCL)
+		bdput(claiming);
+put_disk:
+	if (ret)
+		put_disk_and_module(disk);
+	if (ret == -ERESTARTSYS)
+		goto retry;
 bdput:
-	bdput(bdev);
+	if (ret)
+		bdput(bdev);
 	return ret;
 }
 
@@ -1749,8 +1735,6 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
 		if (bdev_is_partition(bdev))
 			victim = bdev->bd_contains;
 		bdev->bd_contains = NULL;
-
-		put_disk_and_module(disk);
 	} else {
 		if (!bdev_is_partition(bdev) && disk->fops->release)
 			disk->fops->release(disk, mode);
@@ -1763,6 +1747,8 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
 
 void blkdev_put(struct block_device *bdev, fmode_t mode)
 {
+	struct gendisk *disk = bdev->bd_disk;
+
 	mutex_lock(&bdev->bd_mutex);
 
 	if (mode & FMODE_EXCL) {
@@ -1791,7 +1777,7 @@ void blkdev_put(struct block_device *bdev, fmode_t mode)
 		 * unblock evpoll if it was a write holder.
 		 */
 		if (bdev_free && bdev->bd_write_holder) {
-			disk_unblock_events(bdev->bd_disk);
+			disk_unblock_events(disk);
 			bdev->bd_write_holder = false;
 		}
 	}
@@ -1801,11 +1787,12 @@ void blkdev_put(struct block_device *bdev, fmode_t mode)
 	 * event.  This is to ensure detection of media removal commanded
 	 * from userland - e.g. eject(1).
 	 */
-	disk_flush_events(bdev->bd_disk, DISK_EVENT_MEDIA_CHANGE);
+	disk_flush_events(disk, DISK_EVENT_MEDIA_CHANGE);
 
 	mutex_unlock(&bdev->bd_mutex);
 
 	__blkdev_put(bdev, mode, 0);
+	put_disk_and_module(disk);
 }
 EXPORT_SYMBOL(blkdev_put);
 
-- 
2.29.2

--
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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 22/45] block: opencode devcgroup_inode_permission
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (20 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 21/45] block: refactor blkdev_get Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 18:05   ` Tejun Heo
  2020-11-24 13:27 ` [dm-devel] [PATCH 23/45] block: remove i_bdev Christoph Hellwig
                   ` (22 subsequent siblings)
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Just call devcgroup_check_permission to avoid various superflous checks
and a double conversion of the access flags.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/block_dev.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 2ffa11a95f10db..1e35faf6dad42c 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1515,15 +1515,13 @@ static int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
 	struct block_device *claiming;
 	bool unblock_events = true;
 	struct gendisk *disk;
-	int perm = 0;
 	int partno;
 	int ret;
 
-	if (mode & FMODE_READ)
-		perm |= MAY_READ;
-	if (mode & FMODE_WRITE)
-		perm |= MAY_WRITE;
-	ret = devcgroup_inode_permission(bdev->bd_inode, perm);
+	ret = devcgroup_check_permission(DEVCG_DEV_BLOCK,
+			imajor(bdev->bd_inode), iminor(bdev->bd_inode),
+			((mode & FMODE_READ) ? DEVCG_ACC_READ : 0) |
+			((mode & FMODE_WRITE) ? DEVCG_ACC_WRITE : 0));
 	if (ret)
 		goto bdput;
 
-- 
2.29.2

--
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https://www.redhat.com/mailman/listinfo/dm-devel


^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 23/45] block: remove i_bdev
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (21 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 22/45] block: opencode devcgroup_inode_permission Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 13:38   ` Coly Li
  2020-11-24 19:37   ` Tejun Heo
  2020-11-24 13:27 ` [dm-devel] [PATCH 24/45] blk-cgroup: stop abusing get_gendisk Christoph Hellwig
                   ` (21 subsequent siblings)
  44 siblings, 2 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Switch the block device lookup interfaces to directly work with a dev_t
so that struct block_device references are only acquired by the
blkdev_get variants (and the blk-cgroup special case).  This means that
we not don't need an extra reference in the inode and can generally
simplify handling of struct block_device to keep the lookups contained
in the core block layer code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/ioctl.c                                |   3 +-
 drivers/block/loop.c                         |   8 +-
 drivers/md/bcache/super.c                    |  20 +-
 drivers/md/dm-table.c                        |   9 +-
 drivers/mtd/mtdsuper.c                       |  17 +-
 drivers/target/target_core_file.c            |   6 +-
 drivers/usb/gadget/function/storage_common.c |   8 +-
 fs/block_dev.c                               | 195 +++++--------------
 fs/btrfs/volumes.c                           |  13 +-
 fs/inode.c                                   |   3 -
 fs/internal.h                                |   7 +-
 fs/io_uring.c                                |  10 +-
 fs/pipe.c                                    |   5 +-
 fs/quota/quota.c                             |  19 +-
 fs/statfs.c                                  |   2 +-
 fs/super.c                                   |  37 ++--
 include/linux/blkdev.h                       |   2 +-
 include/linux/fs.h                           |   1 -
 18 files changed, 114 insertions(+), 251 deletions(-)

diff --git a/block/ioctl.c b/block/ioctl.c
index 0c09bb7a6ff35f..a6d8171221c7dc 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -590,8 +590,7 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
 {
 	int ret;
 	void __user *argp = compat_ptr(arg);
-	struct inode *inode = file->f_mapping->host;
-	struct block_device *bdev = inode->i_bdev;
+	struct block_device *bdev = I_BDEV(file->f_mapping->host);
 	struct gendisk *disk = bdev->bd_disk;
 	fmode_t mode = file->f_mode;
 	loff_t size;
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index b42c728620c9e4..26c7aafba7c5f8 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -675,10 +675,10 @@ static int loop_validate_file(struct file *file, struct block_device *bdev)
 	while (is_loop_device(f)) {
 		struct loop_device *l;
 
-		if (f->f_mapping->host->i_bdev == bdev)
+		if (f->f_mapping->host->i_rdev == bdev->bd_dev)
 			return -EBADF;
 
-		l = f->f_mapping->host->i_bdev->bd_disk->private_data;
+		l = I_BDEV(f->f_mapping->host)->bd_disk->private_data;
 		if (l->lo_state != Lo_bound) {
 			return -EINVAL;
 		}
@@ -885,9 +885,7 @@ static void loop_config_discard(struct loop_device *lo)
 	 * file-backed loop devices: discarded regions read back as zero.
 	 */
 	if (S_ISBLK(inode->i_mode) && !lo->lo_encrypt_key_size) {
-		struct request_queue *backingq;
-
-		backingq = bdev_get_queue(inode->i_bdev);
+		struct request_queue *backingq = bdev_get_queue(I_BDEV(inode));
 
 		max_discard_sectors = backingq->limits.max_write_zeroes_sectors;
 		granularity = backingq->limits.discard_granularity ?:
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index a6a5e21e4fd136..c55d3c58a7ef55 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -2380,38 +2380,38 @@ kobj_attribute_write(register,		register_bcache);
 kobj_attribute_write(register_quiet,	register_bcache);
 kobj_attribute_write(pendings_cleanup,	bch_pending_bdevs_cleanup);
 
-static bool bch_is_open_backing(struct block_device *bdev)
+static bool bch_is_open_backing(dev_t dev)
 {
 	struct cache_set *c, *tc;
 	struct cached_dev *dc, *t;
 
 	list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
 		list_for_each_entry_safe(dc, t, &c->cached_devs, list)
-			if (dc->bdev == bdev)
+			if (dc->bdev->bd_dev == dev)
 				return true;
 	list_for_each_entry_safe(dc, t, &uncached_devices, list)
-		if (dc->bdev == bdev)
+		if (dc->bdev->bd_dev == dev)
 			return true;
 	return false;
 }
 
-static bool bch_is_open_cache(struct block_device *bdev)
+static bool bch_is_open_cache(dev_t dev)
 {
 	struct cache_set *c, *tc;
 
 	list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
 		struct cache *ca = c->cache;
 
-		if (ca->bdev == bdev)
+		if (ca->bdev->bd_dev == dev)
 			return true;
 	}
 
 	return false;
 }
 
-static bool bch_is_open(struct block_device *bdev)
+static bool bch_is_open(dev_t dev)
 {
-	return bch_is_open_cache(bdev) || bch_is_open_backing(bdev);
+	return bch_is_open_cache(dev) || bch_is_open_backing(dev);
 }
 
 struct async_reg_args {
@@ -2535,9 +2535,11 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 				  sb);
 	if (IS_ERR(bdev)) {
 		if (bdev == ERR_PTR(-EBUSY)) {
-			bdev = lookup_bdev(strim(path));
+			dev_t dev;
+
 			mutex_lock(&bch_register_lock);
-			if (!IS_ERR(bdev) && bch_is_open(bdev))
+			if (lookup_bdev(strim(path), &dev) == 0 &&
+			    bch_is_open(dev))
 				err = "device already registered";
 			else
 				err = "device busy";
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index ce543b761be7b2..dea67772171053 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -348,16 +348,9 @@ static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode,
 dev_t dm_get_dev_t(const char *path)
 {
 	dev_t dev;
-	struct block_device *bdev;
 
-	bdev = lookup_bdev(path);
-	if (IS_ERR(bdev))
+	if (lookup_bdev(path, &dev))
 		dev = name_to_dev_t(path);
-	else {
-		dev = bdev->bd_dev;
-		bdput(bdev);
-	}
-
 	return dev;
 }
 EXPORT_SYMBOL_GPL(dm_get_dev_t);
diff --git a/drivers/mtd/mtdsuper.c b/drivers/mtd/mtdsuper.c
index c3e2098372f2e5..38b6aa849c6383 100644
--- a/drivers/mtd/mtdsuper.c
+++ b/drivers/mtd/mtdsuper.c
@@ -120,8 +120,8 @@ int get_tree_mtd(struct fs_context *fc,
 				struct fs_context *fc))
 {
 #ifdef CONFIG_BLOCK
-	struct block_device *bdev;
-	int ret, major;
+	dev_t dev;
+	int ret;
 #endif
 	int mtdnr;
 
@@ -169,20 +169,15 @@ int get_tree_mtd(struct fs_context *fc,
 	/* try the old way - the hack where we allowed users to mount
 	 * /dev/mtdblock$(n) but didn't actually _use_ the blockdev
 	 */
-	bdev = lookup_bdev(fc->source);
-	if (IS_ERR(bdev)) {
-		ret = PTR_ERR(bdev);
+	ret = lookup_bdev(fc->source, &dev);
+	if (ret) {
 		errorf(fc, "MTD: Couldn't look up '%s': %d", fc->source, ret);
 		return ret;
 	}
 	pr_debug("MTDSB: lookup_bdev() returned 0\n");
 
-	major = MAJOR(bdev->bd_dev);
-	mtdnr = MINOR(bdev->bd_dev);
-	bdput(bdev);
-
-	if (major == MTD_BLOCK_MAJOR)
-		return mtd_get_sb_by_nr(fc, mtdnr, fill_super);
+	if (MAJOR(dev) == MTD_BLOCK_MAJOR)
+		return mtd_get_sb_by_nr(fc, MINOR(dev), fill_super);
 
 #endif /* CONFIG_BLOCK */
 
diff --git a/drivers/target/target_core_file.c b/drivers/target/target_core_file.c
index 7143d03f0e027e..b0cb5b95e892d3 100644
--- a/drivers/target/target_core_file.c
+++ b/drivers/target/target_core_file.c
@@ -133,10 +133,10 @@ static int fd_configure_device(struct se_device *dev)
 	 */
 	inode = file->f_mapping->host;
 	if (S_ISBLK(inode->i_mode)) {
-		struct request_queue *q = bdev_get_queue(inode->i_bdev);
+		struct request_queue *q = bdev_get_queue(I_BDEV(inode));
 		unsigned long long dev_size;
 
-		fd_dev->fd_block_size = bdev_logical_block_size(inode->i_bdev);
+		fd_dev->fd_block_size = bdev_logical_block_size(I_BDEV(inode));
 		/*
 		 * Determine the number of bytes from i_size_read() minus
 		 * one (1) logical sector from underlying struct block_device
@@ -559,7 +559,7 @@ fd_execute_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb)
 
 	if (S_ISBLK(inode->i_mode)) {
 		/* The backend is block device, use discard */
-		struct block_device *bdev = inode->i_bdev;
+		struct block_device *bdev = I_BDEV(inode);
 		struct se_device *dev = cmd->se_dev;
 
 		ret = blkdev_issue_discard(bdev,
diff --git a/drivers/usb/gadget/function/storage_common.c b/drivers/usb/gadget/function/storage_common.c
index f7e6c42558eb76..b859a158a4140e 100644
--- a/drivers/usb/gadget/function/storage_common.c
+++ b/drivers/usb/gadget/function/storage_common.c
@@ -204,7 +204,7 @@ int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
 	if (!(filp->f_mode & FMODE_WRITE))
 		ro = 1;
 
-	inode = file_inode(filp);
+	inode = filp->f_mapping->host;
 	if ((!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))) {
 		LINFO(curlun, "invalid file type: %s\n", filename);
 		goto out;
@@ -221,7 +221,7 @@ int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
 	if (!(filp->f_mode & FMODE_CAN_WRITE))
 		ro = 1;
 
-	size = i_size_read(inode->i_mapping->host);
+	size = i_size_read(inode);
 	if (size < 0) {
 		LINFO(curlun, "unable to find file size: %s\n", filename);
 		rc = (int) size;
@@ -231,8 +231,8 @@ int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
 	if (curlun->cdrom) {
 		blksize = 2048;
 		blkbits = 11;
-	} else if (inode->i_bdev) {
-		blksize = bdev_logical_block_size(inode->i_bdev);
+	} else if (S_ISBLK(inode->i_mode)) {
+		blksize = bdev_logical_block_size(I_BDEV(inode));
 		blkbits = blksize_bits(blksize);
 	} else {
 		blksize = 512;
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 1e35faf6dad42c..c0d1e8248ffe23 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -883,7 +883,6 @@ static struct block_device *bdget(dev_t dev)
 		bdev->bd_dev = dev;
 		inode->i_mode = S_IFBLK;
 		inode->i_rdev = dev;
-		inode->i_bdev = bdev;
 		inode->i_data.a_ops = &def_blk_aops;
 		mapping_set_gfp_mask(&inode->i_data, GFP_USER);
 		unlock_new_inode(inode);
@@ -924,67 +923,8 @@ void bdput(struct block_device *bdev)
 {
 	iput(bdev->bd_inode);
 }
-
 EXPORT_SYMBOL(bdput);
  
-static struct block_device *bd_acquire(struct inode *inode)
-{
-	struct block_device *bdev;
-
-	spin_lock(&bdev_lock);
-	bdev = inode->i_bdev;
-	if (bdev && !inode_unhashed(bdev->bd_inode)) {
-		bdgrab(bdev);
-		spin_unlock(&bdev_lock);
-		return bdev;
-	}
-	spin_unlock(&bdev_lock);
-
-	/*
-	 * i_bdev references block device inode that was already shut down
-	 * (corresponding device got removed).  Remove the reference and look
-	 * up block device inode again just in case new device got
-	 * reestablished under the same device number.
-	 */
-	if (bdev)
-		bd_forget(inode);
-
-	bdev = bdget(inode->i_rdev);
-	if (bdev) {
-		spin_lock(&bdev_lock);
-		if (!inode->i_bdev) {
-			/*
-			 * We take an additional reference to bd_inode,
-			 * and it's released in clear_inode() of inode.
-			 * So, we can access it via ->i_mapping always
-			 * without igrab().
-			 */
-			bdgrab(bdev);
-			inode->i_bdev = bdev;
-			inode->i_mapping = bdev->bd_inode->i_mapping;
-		}
-		spin_unlock(&bdev_lock);
-	}
-	return bdev;
-}
-
-/* Call when you free inode */
-
-void bd_forget(struct inode *inode)
-{
-	struct block_device *bdev = NULL;
-
-	spin_lock(&bdev_lock);
-	if (!sb_is_blkdev_sb(inode->i_sb))
-		bdev = inode->i_bdev;
-	inode->i_bdev = NULL;
-	inode->i_mapping = &inode->i_data;
-	spin_unlock(&bdev_lock);
-
-	if (bdev)
-		bdput(bdev);
-}
-
 /**
  * bd_may_claim - test whether a block device can be claimed
  * @bdev: block device of interest
@@ -1492,38 +1432,45 @@ static int __blkdev_get(struct block_device *bdev, struct gendisk *disk,
 }
 
 /**
- * blkdev_get - open a block device
- * @bdev: block_device to open
+ * blkdev_get_by_dev - open a block device by device number
+ * @dev: device number of block device to open
  * @mode: FMODE_* mask
  * @holder: exclusive holder identifier
  *
- * Open @bdev with @mode.  If @mode includes %FMODE_EXCL, @bdev is
- * open with exclusive access.  Specifying %FMODE_EXCL with %NULL
- * @holder is invalid.  Exclusive opens may nest for the same @holder.
+ * Open the block device described by device number @dev.  If @mode includes
+ * If @mode includes %FMODE_EXCL, the block device is opened with exclusive
+ * access.  Specifying %FMODE_EXCL with a %NULL @holder is invalid.  Exclusive
+ * opens may nest for the same @holder.
  *
- * On success, the reference count of @bdev is unchanged.  On failure,
- * @bdev is put.
+ * Use this interface ONLY if you really do not have anything better - i.e. when
+ * you are behind a truly sucky interface and all you are given is a device
+ * number.  Everything else should use blkdev_get_by_path().
  *
  * CONTEXT:
  * Might sleep.
  *
  * RETURNS:
- * 0 on success, -errno on failure.
+ * Reference to the block_device on success, ERR_PTR(-errno) on failure.
  */
-static int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
+struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 {
 	struct block_device *claiming;
 	bool unblock_events = true;
+	struct block_device *bdev;
 	struct gendisk *disk;
 	int partno;
 	int ret;
 
 	ret = devcgroup_check_permission(DEVCG_DEV_BLOCK,
-			imajor(bdev->bd_inode), iminor(bdev->bd_inode),
+			MAJOR(dev), MINOR(dev),
 			((mode & FMODE_READ) ? DEVCG_ACC_READ : 0) |
 			((mode & FMODE_WRITE) ? DEVCG_ACC_WRITE : 0));
 	if (ret)
-		goto bdput;
+		return ERR_PTR(ret);
+
+	bdev = bdget(dev);
+	if (!bdev)
+		return ERR_PTR(-ENOMEM);
 
 	/*
 	 * If we lost a race with 'disk' being deleted, try again.  See md.c.
@@ -1584,10 +1531,13 @@ static int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
 	if (ret == -ERESTARTSYS)
 		goto retry;
 bdput:
-	if (ret)
+	if (ret) {
 		bdput(bdev);
-	return ret;
+		return ERR_PTR(ret);
+	}
+	return bdev;
 }
+EXPORT_SYMBOL(blkdev_get_by_dev);
 
 /**
  * blkdev_get_by_path - open a block device by name
@@ -1595,32 +1545,31 @@ static int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
  * @mode: FMODE_* mask
  * @holder: exclusive holder identifier
  *
- * Open the blockdevice described by the device file at @path.  @mode
- * and @holder are identical to blkdev_get().
+ * Open the block device described by the device file at &path.
  *
- * On success, the returned block_device has reference count of one.
+ * If @mode includes %FMODE_EXCL, the block device is opened with exclusive
+ * access.  Specifying %FMODE_EXCL with a %NULL @holder is invalid.  Exclusive
+ * opens may nest for the same @holder.
  *
  * CONTEXT:
  * Might sleep.
  *
  * RETURNS:
- * Pointer to block_device on success, ERR_PTR(-errno) on failure.
+ * Reference to the block_device on success, ERR_PTR(-errno) on failure.
  */
 struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
 					void *holder)
 {
 	struct block_device *bdev;
-	int err;
-
-	bdev = lookup_bdev(path);
-	if (IS_ERR(bdev))
-		return bdev;
+	dev_t dev;
+	int error;
 
-	err = blkdev_get(bdev, mode, holder);
-	if (err)
-		return ERR_PTR(err);
+	error = lookup_bdev(path, &dev);
+	if (error)
+		return ERR_PTR(error);
 
-	if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) {
+	bdev = blkdev_get_by_dev(dev, mode, holder);
+	if (!IS_ERR(bdev) && (mode & FMODE_WRITE) && bdev_read_only(bdev)) {
 		blkdev_put(bdev, mode);
 		return ERR_PTR(-EACCES);
 	}
@@ -1629,45 +1578,6 @@ struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
 }
 EXPORT_SYMBOL(blkdev_get_by_path);
 
-/**
- * blkdev_get_by_dev - open a block device by device number
- * @dev: device number of block device to open
- * @mode: FMODE_* mask
- * @holder: exclusive holder identifier
- *
- * Open the blockdevice described by device number @dev.  @mode and
- * @holder are identical to blkdev_get().
- *
- * Use it ONLY if you really do not have anything better - i.e. when
- * you are behind a truly sucky interface and all you are given is a
- * device number.  _Never_ to be used for internal purposes.  If you
- * ever need it - reconsider your API.
- *
- * On success, the returned block_device has reference count of one.
- *
- * CONTEXT:
- * Might sleep.
- *
- * RETURNS:
- * Pointer to block_device on success, ERR_PTR(-errno) on failure.
- */
-struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
-{
-	struct block_device *bdev;
-	int err;
-
-	bdev = bdget(dev);
-	if (!bdev)
-		return ERR_PTR(-ENOMEM);
-
-	err = blkdev_get(bdev, mode, holder);
-	if (err)
-		return ERR_PTR(err);
-
-	return bdev;
-}
-EXPORT_SYMBOL(blkdev_get_by_dev);
-
 static int blkdev_open(struct inode * inode, struct file * filp)
 {
 	struct block_device *bdev;
@@ -1689,14 +1599,12 @@ static int blkdev_open(struct inode * inode, struct file * filp)
 	if ((filp->f_flags & O_ACCMODE) == 3)
 		filp->f_mode |= FMODE_WRITE_IOCTL;
 
-	bdev = bd_acquire(inode);
-	if (bdev == NULL)
-		return -ENOMEM;
-
+	bdev = blkdev_get_by_dev(inode->i_rdev, filp->f_mode, filp);
+	if (IS_ERR(bdev))
+		return PTR_ERR(bdev);
 	filp->f_mapping = bdev->bd_inode->i_mapping;
 	filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
-
-	return blkdev_get(bdev, filp->f_mode, filp);
+	return 0;
 }
 
 static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
@@ -2003,37 +1911,32 @@ const struct file_operations def_blk_fops = {
  * namespace if possible and return it.  Return ERR_PTR(error)
  * otherwise.
  */
-struct block_device *lookup_bdev(const char *pathname)
+int lookup_bdev(const char *pathname, dev_t *dev)
 {
-	struct block_device *bdev;
 	struct inode *inode;
 	struct path path;
 	int error;
 
 	if (!pathname || !*pathname)
-		return ERR_PTR(-EINVAL);
+		return -EINVAL;
 
 	error = kern_path(pathname, LOOKUP_FOLLOW, &path);
 	if (error)
-		return ERR_PTR(error);
+		return error;
 
 	inode = d_backing_inode(path.dentry);
 	error = -ENOTBLK;
 	if (!S_ISBLK(inode->i_mode))
-		goto fail;
+		goto out_path_put;
 	error = -EACCES;
 	if (!may_open_dev(&path))
-		goto fail;
-	error = -ENOMEM;
-	bdev = bd_acquire(inode);
-	if (!bdev)
-		goto fail;
-out:
+		goto out_path_put;
+
+	*dev = inode->i_rdev;
+	error = 0;
+out_path_put:
 	path_put(&path);
-	return bdev;
-fail:
-	bdev = ERR_PTR(error);
-	goto out;
+	return error;
 }
 EXPORT_SYMBOL(lookup_bdev);
 
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index a6406b3b8c2b4f..fbc4b58228f784 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -929,16 +929,16 @@ static noinline struct btrfs_device *device_list_add(const char *path,
 		 * make sure it's the same device if the device is mounted
 		 */
 		if (device->bdev) {
-			struct block_device *path_bdev;
+			int error;
+			dev_t path_dev;
 
-			path_bdev = lookup_bdev(path);
-			if (IS_ERR(path_bdev)) {
+			error = lookup_bdev(path, &path_dev);
+			if (error) {
 				mutex_unlock(&fs_devices->device_list_mutex);
-				return ERR_CAST(path_bdev);
+				return ERR_PTR(error);
 			}
 
-			if (device->bdev != path_bdev) {
-				bdput(path_bdev);
+			if (device->bdev->bd_dev != path_dev) {
 				mutex_unlock(&fs_devices->device_list_mutex);
 				btrfs_warn_in_rcu(device->fs_info,
 	"duplicate device %s devid %llu generation %llu scanned by %s (%d)",
@@ -947,7 +947,6 @@ static noinline struct btrfs_device *device_list_add(const char *path,
 						  task_pid_nr(current));
 				return ERR_PTR(-EEXIST);
 			}
-			bdput(path_bdev);
 			btrfs_info_in_rcu(device->fs_info,
 	"devid %llu device path %s changed to %s scanned by %s (%d)",
 					  devid, rcu_str_deref(device->name),
diff --git a/fs/inode.c b/fs/inode.c
index 9d78c37b00b817..cb008acf0efdb8 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -155,7 +155,6 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
 	inode->i_bytes = 0;
 	inode->i_generation = 0;
 	inode->i_pipe = NULL;
-	inode->i_bdev = NULL;
 	inode->i_cdev = NULL;
 	inode->i_link = NULL;
 	inode->i_dir_seq = 0;
@@ -580,8 +579,6 @@ static void evict(struct inode *inode)
 		truncate_inode_pages_final(&inode->i_data);
 		clear_inode(inode);
 	}
-	if (S_ISBLK(inode->i_mode) && inode->i_bdev)
-		bd_forget(inode);
 	if (S_ISCHR(inode->i_mode) && inode->i_cdev)
 		cd_forget(inode);
 
diff --git a/fs/internal.h b/fs/internal.h
index 47be21dfeebef5..53f890446e7508 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -25,7 +25,6 @@ extern void __init bdev_cache_init(void);
 extern int __sync_blockdev(struct block_device *bdev, int wait);
 void iterate_bdevs(void (*)(struct block_device *, void *), void *);
 void emergency_thaw_bdev(struct super_block *sb);
-void bd_forget(struct inode *inode);
 #else
 static inline void bdev_cache_init(void)
 {
@@ -43,9 +42,6 @@ static inline int emergency_thaw_bdev(struct super_block *sb)
 {
 	return 0;
 }
-static inline void bd_forget(struct inode *inode)
-{
-}
 #endif /* CONFIG_BLOCK */
 
 /*
@@ -114,8 +110,7 @@ extern struct file *alloc_empty_file_noaccount(int, const struct cred *);
  */
 extern int reconfigure_super(struct fs_context *);
 extern bool trylock_super(struct super_block *sb);
-struct super_block *__get_super(struct block_device *bdev, bool excl);
-extern struct super_block *user_get_super(dev_t);
+struct super_block *user_get_super(dev_t, bool excl);
 void put_super(struct super_block *sb);
 extern bool mount_capable(struct fs_context *);
 
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 4ead291b2976f3..8f13c0417f940c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2716,11 +2716,7 @@ static struct file *__io_file_get(struct io_submit_state *state, int fd)
 
 static bool io_bdev_nowait(struct block_device *bdev)
 {
-#ifdef CONFIG_BLOCK
 	return !bdev || blk_queue_nowait(bdev_get_queue(bdev));
-#else
-	return true;
-#endif
 }
 
 /*
@@ -2733,14 +2729,16 @@ static bool io_file_supports_async(struct file *file, int rw)
 	umode_t mode = file_inode(file)->i_mode;
 
 	if (S_ISBLK(mode)) {
-		if (io_bdev_nowait(file->f_inode->i_bdev))
+		if (IS_ENABLED(CONFIG_BLOCK) &&
+		    io_bdev_nowait(I_BDEV(file->f_mapping->host)))
 			return true;
 		return false;
 	}
 	if (S_ISCHR(mode) || S_ISSOCK(mode))
 		return true;
 	if (S_ISREG(mode)) {
-		if (io_bdev_nowait(file->f_inode->i_sb->s_bdev) &&
+		if (IS_ENABLED(CONFIG_BLOCK) &&
+		    io_bdev_nowait(file->f_inode->i_sb->s_bdev) &&
 		    file->f_op != &io_uring_fops)
 			return true;
 		return false;
diff --git a/fs/pipe.c b/fs/pipe.c
index 0ac197658a2d6e..c5989cfd564d45 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -1342,9 +1342,8 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long arg)
 }
 
 /*
- * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same
- * location, so checking ->i_pipe is not enough to verify that this is a
- * pipe.
+ * Note that i_pipe and i_cdev share the same location, so checking ->i_pipe is
+ * not enough to verify that this is a pipe.
  */
 struct pipe_inode_info *get_pipe_info(struct file *file, bool for_splice)
 {
diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index f3d32b0d9008f2..6d16b2be5ac4a3 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -866,17 +866,18 @@ static bool quotactl_cmd_onoff(int cmd)
 static struct super_block *quotactl_block(const char __user *special, int cmd)
 {
 #ifdef CONFIG_BLOCK
-	struct block_device *bdev;
 	struct super_block *sb;
 	struct filename *tmp = getname(special);
 	bool excl = false, thawed = false;
+	int error;
+	dev_t dev;
 
 	if (IS_ERR(tmp))
 		return ERR_CAST(tmp);
-	bdev = lookup_bdev(tmp->name);
+	error = lookup_bdev(tmp->name, &dev);
 	putname(tmp);
-	if (IS_ERR(bdev))
-		return ERR_CAST(bdev);
+	if (error)
+		return ERR_PTR(error);
 
 	if (quotactl_cmd_onoff(cmd)) {
 		excl = true;
@@ -886,8 +887,10 @@ static struct super_block *quotactl_block(const char __user *special, int cmd)
 	}
 
 retry:
-	sb = __get_super(bdev, excl);
-	if (thawed && sb && sb->s_writers.frozen != SB_UNFROZEN) {
+	sb = user_get_super(dev, excl);
+	if (!sb)
+		return ERR_PTR(-ENODEV);
+	if (thawed && sb->s_writers.frozen != SB_UNFROZEN) {
 		if (excl)
 			up_write(&sb->s_umount);
 		else
@@ -897,10 +900,6 @@ static struct super_block *quotactl_block(const char __user *special, int cmd)
 		put_super(sb);
 		goto retry;
 	}
-
-	bdput(bdev);
-	if (!sb)
-		return ERR_PTR(-ENODEV);
 	return sb;
 
 #else
diff --git a/fs/statfs.c b/fs/statfs.c
index 59f33752c1311f..68cb077887504f 100644
--- a/fs/statfs.c
+++ b/fs/statfs.c
@@ -235,7 +235,7 @@ SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user
 
 static int vfs_ustat(dev_t dev, struct kstatfs *sbuf)
 {
-	struct super_block *s = user_get_super(dev);
+	struct super_block *s = user_get_super(dev, false);
 	int err;
 	if (!s)
 		return -EINVAL;
diff --git a/fs/super.c b/fs/super.c
index 343e5c1e538d2a..7a1611e5d0f45d 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -740,7 +740,7 @@ void iterate_supers_type(struct file_system_type *type,
 
 EXPORT_SYMBOL(iterate_supers_type);
 
-struct super_block *__get_super(struct block_device *bdev, bool excl)
+struct super_block *get_super(struct block_device *bdev)
 {
 	struct super_block *sb;
 
@@ -755,17 +755,11 @@ struct super_block *__get_super(struct block_device *bdev, bool excl)
 		if (sb->s_bdev == bdev) {
 			sb->s_count++;
 			spin_unlock(&sb_lock);
-			if (!excl)
-				down_read(&sb->s_umount);
-			else
-				down_write(&sb->s_umount);
+			down_read(&sb->s_umount);
 			/* still alive? */
 			if (sb->s_root && (sb->s_flags & SB_BORN))
 				return sb;
-			if (!excl)
-				up_read(&sb->s_umount);
-			else
-				up_write(&sb->s_umount);
+			up_read(&sb->s_umount);
 			/* nope, got unmounted */
 			spin_lock(&sb_lock);
 			__put_super(sb);
@@ -776,19 +770,6 @@ struct super_block *__get_super(struct block_device *bdev, bool excl)
 	return NULL;
 }
 
-/**
- *	get_super - get the superblock of a device
- *	@bdev: device to get the superblock for
- *
- *	Scans the superblock list and finds the superblock of the file system
- *	mounted on the device given. %NULL is returned if no match is found.
- */
-struct super_block *get_super(struct block_device *bdev)
-{
-	return __get_super(bdev, false);
-}
-EXPORT_SYMBOL(get_super);
-
 /**
  * get_active_super - get an active reference to the superblock of a device
  * @bdev: device to get the superblock for
@@ -820,7 +801,7 @@ struct super_block *get_active_super(struct block_device *bdev)
 	return NULL;
 }
 
-struct super_block *user_get_super(dev_t dev)
+struct super_block *user_get_super(dev_t dev, bool excl)
 {
 	struct super_block *sb;
 
@@ -832,11 +813,17 @@ struct super_block *user_get_super(dev_t dev)
 		if (sb->s_dev ==  dev) {
 			sb->s_count++;
 			spin_unlock(&sb_lock);
-			down_read(&sb->s_umount);
+			if (excl)
+				down_write(&sb->s_umount);
+			else
+				down_read(&sb->s_umount);
 			/* still alive? */
 			if (sb->s_root && (sb->s_flags & SB_BORN))
 				return sb;
-			up_read(&sb->s_umount);
+			if (excl)
+				up_write(&sb->s_umount);
+			else
+				up_read(&sb->s_umount);
 			/* nope, got unmounted */
 			spin_lock(&sb_lock);
 			__put_super(sb);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 12810a19edebc4..bdd7339bcda462 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1973,7 +1973,7 @@ int bdev_read_only(struct block_device *bdev);
 int set_blocksize(struct block_device *bdev, int size);
 
 const char *bdevname(struct block_device *bdev, char *buffer);
-struct block_device *lookup_bdev(const char *);
+int lookup_bdev(const char *pathname, dev_t *dev);
 
 void blkdev_show(struct seq_file *seqf, off_t offset);
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index a61df0dd4f1989..b0b358309657ba 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -696,7 +696,6 @@ struct inode {
 	struct list_head	i_devices;
 	union {
 		struct pipe_inode_info	*i_pipe;
-		struct block_device	*i_bdev;
 		struct cdev		*i_cdev;
 		char			*i_link;
 		unsigned		i_dir_seq;
-- 
2.29.2

--
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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 24/45] blk-cgroup: stop abusing get_gendisk
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (22 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 23/45] block: remove i_bdev Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 19:46   ` Tejun Heo
  2020-11-24 13:27 ` [dm-devel] [PATCH 25/45] block: reference struct block_device from struct hd_struct Christoph Hellwig
                   ` (20 subsequent siblings)
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Properly open the device instead of relying on deep internals by
using get_gendisk.  Note that this uses FMODE_NDELAY without either
FMODE_READ or FMODE_WRITE, which is a special open mode to allow
for opening without media access, thus avoiding unexpexted interactions
especially on removable media.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-cgroup.c         | 42 +++++++++++++++++++-------------------
 block/blk-iocost.c         | 36 ++++++++++++++++----------------
 include/linux/blk-cgroup.h |  4 ++--
 3 files changed, 41 insertions(+), 41 deletions(-)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 54fbe1e80cc41a..23437b96ea41e6 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -556,22 +556,22 @@ static struct blkcg_gq *blkg_lookup_check(struct blkcg *blkcg,
 }
 
 /**
- * blkg_conf_prep - parse and prepare for per-blkg config update
+ * blkcg_conf_open_bdev - parse and open bdev for per-blkg config update
  * @inputp: input string pointer
  *
  * Parse the device node prefix part, MAJ:MIN, of per-blkg config update
- * from @input and get and return the matching gendisk.  *@inputp is
+ * from @input and get and return the matching bdev.  *@inputp is
  * updated to point past the device node prefix.  Returns an ERR_PTR()
  * value on error.
  *
  * Use this function iff blkg_conf_prep() can't be used for some reason.
  */
-struct gendisk *blkcg_conf_get_disk(char **inputp)
+struct block_device *blkcg_conf_open_bdev(char **inputp)
 {
 	char *input = *inputp;
 	unsigned int major, minor;
-	struct gendisk *disk;
-	int key_len, part;
+	struct block_device *bdev;
+	int key_len;
 
 	if (sscanf(input, "%u:%u%n", &major, &minor, &key_len) != 2)
 		return ERR_PTR(-EINVAL);
@@ -581,16 +581,16 @@ struct gendisk *blkcg_conf_get_disk(char **inputp)
 		return ERR_PTR(-EINVAL);
 	input = skip_spaces(input);
 
-	disk = get_gendisk(MKDEV(major, minor), &part);
-	if (!disk)
+	bdev = blkdev_get_by_dev(MKDEV(major, minor), FMODE_NDELAY, NULL);
+	if (!bdev)
 		return ERR_PTR(-ENODEV);
-	if (part) {
-		put_disk_and_module(disk);
+	if (bdev_is_partition(bdev)) {
+		blkdev_put(bdev, FMODE_NDELAY);
 		return ERR_PTR(-ENODEV);
 	}
 
 	*inputp = input;
-	return disk;
+	return bdev;
 }
 
 /**
@@ -607,18 +607,18 @@ struct gendisk *blkcg_conf_get_disk(char **inputp)
  */
 int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
 		   char *input, struct blkg_conf_ctx *ctx)
-	__acquires(rcu) __acquires(&disk->queue->queue_lock)
+	__acquires(rcu) __acquires(&bdev->bd_disk->queue->queue_lock)
 {
-	struct gendisk *disk;
+	struct block_device *bdev;
 	struct request_queue *q;
 	struct blkcg_gq *blkg;
 	int ret;
 
-	disk = blkcg_conf_get_disk(&input);
-	if (IS_ERR(disk))
-		return PTR_ERR(disk);
+	bdev = blkcg_conf_open_bdev(&input);
+	if (IS_ERR(bdev))
+		return PTR_ERR(bdev);
 
-	q = disk->queue;
+	q = bdev->bd_disk->queue;
 
 	rcu_read_lock();
 	spin_lock_irq(&q->queue_lock);
@@ -689,7 +689,7 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
 			goto success;
 	}
 success:
-	ctx->disk = disk;
+	ctx->bdev = bdev;
 	ctx->blkg = blkg;
 	ctx->body = input;
 	return 0;
@@ -700,7 +700,7 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
 	spin_unlock_irq(&q->queue_lock);
 	rcu_read_unlock();
 fail:
-	put_disk_and_module(disk);
+	blkdev_put(bdev, FMODE_NDELAY);
 	/*
 	 * If queue was bypassing, we should retry.  Do so after a
 	 * short msleep().  It isn't strictly necessary but queue
@@ -723,11 +723,11 @@ EXPORT_SYMBOL_GPL(blkg_conf_prep);
  * with blkg_conf_prep().
  */
 void blkg_conf_finish(struct blkg_conf_ctx *ctx)
-	__releases(&ctx->disk->queue->queue_lock) __releases(rcu)
+	__releases(&ctx->bdev->bd_disk->queue->queue_lock) __releases(rcu)
 {
-	spin_unlock_irq(&ctx->disk->queue->queue_lock);
+	spin_unlock_irq(&ctx->bdev->bd_disk->queue->queue_lock);
 	rcu_read_unlock();
-	put_disk_and_module(ctx->disk);
+	blkdev_put(ctx->bdev, FMODE_NDELAY);
 }
 EXPORT_SYMBOL_GPL(blkg_conf_finish);
 
diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index bbe86d1199dc5b..9f219718e9813c 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -3120,23 +3120,23 @@ static const match_table_t qos_tokens = {
 static ssize_t ioc_qos_write(struct kernfs_open_file *of, char *input,
 			     size_t nbytes, loff_t off)
 {
-	struct gendisk *disk;
+	struct block_device *bdev;
 	struct ioc *ioc;
 	u32 qos[NR_QOS_PARAMS];
 	bool enable, user;
 	char *p;
 	int ret;
 
-	disk = blkcg_conf_get_disk(&input);
-	if (IS_ERR(disk))
-		return PTR_ERR(disk);
+	bdev = blkcg_conf_open_bdev(&input);
+	if (IS_ERR(bdev))
+		return PTR_ERR(bdev);
 
-	ioc = q_to_ioc(disk->queue);
+	ioc = q_to_ioc(bdev->bd_disk->queue);
 	if (!ioc) {
-		ret = blk_iocost_init(disk->queue);
+		ret = blk_iocost_init(bdev->bd_disk->queue);
 		if (ret)
 			goto err;
-		ioc = q_to_ioc(disk->queue);
+		ioc = q_to_ioc(bdev->bd_disk->queue);
 	}
 
 	spin_lock_irq(&ioc->lock);
@@ -3231,12 +3231,12 @@ static ssize_t ioc_qos_write(struct kernfs_open_file *of, char *input,
 	ioc_refresh_params(ioc, true);
 	spin_unlock_irq(&ioc->lock);
 
-	put_disk_and_module(disk);
+	blkdev_put(bdev, FMODE_NDELAY);
 	return nbytes;
 einval:
 	ret = -EINVAL;
 err:
-	put_disk_and_module(disk);
+	blkdev_put(bdev, FMODE_NDELAY);
 	return ret;
 }
 
@@ -3287,23 +3287,23 @@ static const match_table_t i_lcoef_tokens = {
 static ssize_t ioc_cost_model_write(struct kernfs_open_file *of, char *input,
 				    size_t nbytes, loff_t off)
 {
-	struct gendisk *disk;
+	struct block_device *bdev;
 	struct ioc *ioc;
 	u64 u[NR_I_LCOEFS];
 	bool user;
 	char *p;
 	int ret;
 
-	disk = blkcg_conf_get_disk(&input);
-	if (IS_ERR(disk))
-		return PTR_ERR(disk);
+	bdev = blkcg_conf_open_bdev(&input);
+	if (IS_ERR(bdev))
+		return PTR_ERR(bdev);
 
-	ioc = q_to_ioc(disk->queue);
+	ioc = q_to_ioc(bdev->bd_disk->queue);
 	if (!ioc) {
-		ret = blk_iocost_init(disk->queue);
+		ret = blk_iocost_init(bdev->bd_disk->queue);
 		if (ret)
 			goto err;
-		ioc = q_to_ioc(disk->queue);
+		ioc = q_to_ioc(bdev->bd_disk->queue);
 	}
 
 	spin_lock_irq(&ioc->lock);
@@ -3356,13 +3356,13 @@ static ssize_t ioc_cost_model_write(struct kernfs_open_file *of, char *input,
 	ioc_refresh_params(ioc, true);
 	spin_unlock_irq(&ioc->lock);
 
-	put_disk_and_module(disk);
+	blkdev_put(bdev, FMODE_NDELAY);
 	return nbytes;
 
 einval:
 	ret = -EINVAL;
 err:
-	put_disk_and_module(disk);
+	blkdev_put(bdev, FMODE_NDELAY);
 	return ret;
 }
 
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index c8fc9792ac776d..b9f3c246c3c908 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -197,12 +197,12 @@ void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
 u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v);
 
 struct blkg_conf_ctx {
-	struct gendisk			*disk;
+	struct block_device		*bdev;
 	struct blkcg_gq			*blkg;
 	char				*body;
 };
 
-struct gendisk *blkcg_conf_get_disk(char **inputp);
+struct block_device *blkcg_conf_open_bdev(char **inputp);
 int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
 		   char *input, struct blkg_conf_ctx *ctx);
 void blkg_conf_finish(struct blkg_conf_ctx *ctx);
-- 
2.29.2

--
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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 25/45] block: reference struct block_device from struct hd_struct
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (23 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 24/45] blk-cgroup: stop abusing get_gendisk Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 21:18   ` Tejun Heo
  2020-11-24 13:27 ` [dm-devel] [PATCH 26/45] block: remove ->bd_contains Christoph Hellwig
                   ` (19 subsequent siblings)
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

To simplify block device lookup and a few other upcoming areas, make sure
that we always have a struct block_device available for each disk and
each partition.  The only downside of this is that each device and
partition uses a little more memory.  The upside will be that a lot of
code can be simplified.

With that all we need to look up the block device is to lookup the inode
and do a few sanity checks on the gendisk, instead of the separate lookup
for the gendisk.  These checks are in a new RCU critical section and
the disk is now freed using kfree_rcu().

As part of the change switch bdget() to only find existing block devices,
given that we know that the block_device structure must be allocated at
probe / partition scan time.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk.h             |   2 +-
 block/genhd.c           | 212 ++++------------------------------------
 block/partitions/core.c |  29 +++---
 fs/block_dev.c          | 171 ++++++++++++++++++--------------
 include/linux/blkdev.h  |   2 +
 include/linux/genhd.h   |   6 +-
 6 files changed, 140 insertions(+), 282 deletions(-)

diff --git a/block/blk.h b/block/blk.h
index dfab98465db9a5..c4839abcfa27eb 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -352,7 +352,6 @@ struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector);
 
 int blk_alloc_devt(struct hd_struct *part, dev_t *devt);
 void blk_free_devt(dev_t devt);
-void blk_invalidate_devt(dev_t devt);
 char *disk_name(struct gendisk *hd, int partno, char *buf);
 #define ADDPART_FLAG_NONE	0
 #define ADDPART_FLAG_RAID	1
@@ -384,6 +383,7 @@ static inline void hd_free_part(struct hd_struct *part)
 {
 	free_percpu(part->dkstats);
 	kfree(part->info);
+	bdput(part->bdev);
 	percpu_ref_exit(&part->ref);
 }
 
diff --git a/block/genhd.c b/block/genhd.c
index f46e89226fdf91..16c6b13242105b 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -27,17 +27,9 @@
 
 static struct kobject *block_depr;
 
-static DEFINE_XARRAY(bdev_map);
-static DEFINE_MUTEX(bdev_map_lock);
-
 /* for extended dynamic devt allocation, currently only one major is used */
 #define NR_EXT_DEVT		(1 << MINORBITS)
-
-/* For extended devt allocation.  ext_devt_lock prevents look up
- * results from going away underneath its user.
- */
-static DEFINE_SPINLOCK(ext_devt_lock);
-static DEFINE_IDR(ext_devt_idr);
+static DEFINE_IDA(ext_devt_ida);
 
 static void disk_check_events(struct disk_events *ev,
 			      unsigned int *clearing_ptr);
@@ -580,14 +572,7 @@ int blk_alloc_devt(struct hd_struct *part, dev_t *devt)
 		return 0;
 	}
 
-	/* allocate ext devt */
-	idr_preload(GFP_KERNEL);
-
-	spin_lock_bh(&ext_devt_lock);
-	idx = idr_alloc(&ext_devt_idr, part, 0, NR_EXT_DEVT, GFP_NOWAIT);
-	spin_unlock_bh(&ext_devt_lock);
-
-	idr_preload_end();
+	idx = ida_alloc_range(&ext_devt_ida, 0, NR_EXT_DEVT, GFP_KERNEL);
 	if (idx < 0)
 		return idx == -ENOSPC ? -EBUSY : idx;
 
@@ -606,26 +591,8 @@ int blk_alloc_devt(struct hd_struct *part, dev_t *devt)
  */
 void blk_free_devt(dev_t devt)
 {
-	if (devt == MKDEV(0, 0))
-		return;
-
-	if (MAJOR(devt) == BLOCK_EXT_MAJOR) {
-		spin_lock_bh(&ext_devt_lock);
-		idr_remove(&ext_devt_idr, blk_mangle_minor(MINOR(devt)));
-		spin_unlock_bh(&ext_devt_lock);
-	}
-}
-
-/*
- * We invalidate devt by assigning NULL pointer for devt in idr.
- */
-void blk_invalidate_devt(dev_t devt)
-{
-	if (MAJOR(devt) == BLOCK_EXT_MAJOR) {
-		spin_lock_bh(&ext_devt_lock);
-		idr_replace(&ext_devt_idr, NULL, blk_mangle_minor(MINOR(devt)));
-		spin_unlock_bh(&ext_devt_lock);
-	}
+	if (MAJOR(devt) == BLOCK_EXT_MAJOR)
+		ida_free(&ext_devt_ida, blk_mangle_minor(MINOR(devt)));
 }
 
 static char *bdevt_str(dev_t devt, char *buf)
@@ -640,28 +607,6 @@ static char *bdevt_str(dev_t devt, char *buf)
 	return buf;
 }
 
-static void blk_register_region(struct gendisk *disk)
-{
-	int i;
-
-	mutex_lock(&bdev_map_lock);
-	for (i = 0; i < disk->minors; i++) {
-		if (xa_insert(&bdev_map, disk_devt(disk) + i, disk, GFP_KERNEL))
-			WARN_ON_ONCE(1);
-	}
-	mutex_unlock(&bdev_map_lock);
-}
-
-static void blk_unregister_region(struct gendisk *disk)
-{
-	int i;
-
-	mutex_lock(&bdev_map_lock);
-	for (i = 0; i < disk->minors; i++)
-		xa_erase(&bdev_map, disk_devt(disk) + i);
-	mutex_unlock(&bdev_map_lock);
-}
-
 static void disk_scan_partitions(struct gendisk *disk)
 {
 	struct block_device *bdev;
@@ -805,7 +750,7 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
 		ret = bdi_register(bdi, "%u:%u", MAJOR(devt), MINOR(devt));
 		WARN_ON(ret);
 		bdi_set_owner(bdi, dev);
-		blk_register_region(disk);
+		bdev_add(disk->part0.bdev, devt);
 	}
 	register_disk(parent, disk, groups);
 	if (register_queue)
@@ -886,11 +831,8 @@ void del_gendisk(struct gendisk *disk)
 	blk_integrity_del(disk);
 	disk_del_events(disk);
 
-	/*
-	 * Block lookups of the disk until all bdevs are unhashed and the
-	 * disk is marked as dead (GENHD_FL_UP cleared).
-	 */
-	down_write(&disk->lookup_sem);
+	disk->flags &= ~GENHD_FL_UP;
+
 	/* invalidate stuff */
 	disk_part_iter_init(&piter, disk,
 			     DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
@@ -902,8 +844,6 @@ void del_gendisk(struct gendisk *disk)
 
 	invalidate_partition(disk, 0);
 	set_capacity(disk, 0);
-	disk->flags &= ~GENHD_FL_UP;
-	up_write(&disk->lookup_sem);
 
 	if (!(disk->flags & GENHD_FL_HIDDEN)) {
 		sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
@@ -916,16 +856,6 @@ void del_gendisk(struct gendisk *disk)
 	}
 
 	blk_unregister_queue(disk);
-	
-	if (!(disk->flags & GENHD_FL_HIDDEN))
-		blk_unregister_region(disk);
-	/*
-	 * Remove gendisk pointer from idr so that it cannot be looked up
-	 * while RCU period before freeing gendisk is running to prevent
-	 * use-after-free issues. Note that the device number stays
-	 * "in-use" until we really free the gendisk.
-	 */
-	blk_invalidate_devt(disk_devt(disk));
 
 	kobject_put(disk->part0.holder_dir);
 	kobject_put(disk->slave_dir);
@@ -964,7 +894,7 @@ static ssize_t disk_badblocks_store(struct device *dev,
 	return badblocks_store(disk->bb, page, len, 0);
 }
 
-static void request_gendisk_module(dev_t devt)
+void blk_request_module(dev_t devt)
 {
 	unsigned int major = MAJOR(devt);
 	struct blk_major_name **n;
@@ -984,84 +914,6 @@ static void request_gendisk_module(dev_t devt)
 		request_module("block-major-%d", MAJOR(devt));
 }
 
-static bool get_disk_and_module(struct gendisk *disk)
-{
-	struct module *owner;
-
-	if (!disk->fops)
-		return false;
-	owner = disk->fops->owner;
-	if (owner && !try_module_get(owner))
-		return false;
-	if (!kobject_get_unless_zero(&disk_to_dev(disk)->kobj)) {
-		module_put(owner);
-		return false;
-	}
-	return true;
-
-}
-
-/**
- * get_gendisk - get partitioning information for a given device
- * @devt: device to get partitioning information for
- * @partno: returned partition index
- *
- * This function gets the structure containing partitioning
- * information for the given device @devt.
- *
- * Context: can sleep
- */
-struct gendisk *get_gendisk(dev_t devt, int *partno)
-{
-	struct gendisk *disk = NULL;
-
-	might_sleep();
-
-	if (MAJOR(devt) != BLOCK_EXT_MAJOR) {
-		mutex_lock(&bdev_map_lock);
-		disk = xa_load(&bdev_map, devt);
-		if (!disk) {
-			mutex_unlock(&bdev_map_lock);
-			request_gendisk_module(devt);
-			mutex_lock(&bdev_map_lock);
-			disk = xa_load(&bdev_map, devt);
-		}
-		if (disk && !get_disk_and_module(disk))
-			disk = NULL;
-		if (disk)
-			*partno = devt - disk_devt(disk);
-		mutex_unlock(&bdev_map_lock);
-	} else {
-		struct hd_struct *part;
-
-		spin_lock_bh(&ext_devt_lock);
-		part = idr_find(&ext_devt_idr, blk_mangle_minor(MINOR(devt)));
-		if (part && get_disk_and_module(part_to_disk(part))) {
-			*partno = part->partno;
-			disk = part_to_disk(part);
-		}
-		spin_unlock_bh(&ext_devt_lock);
-	}
-
-	if (!disk)
-		return NULL;
-
-	/*
-	 * Synchronize with del_gendisk() to not return disk that is being
-	 * destroyed.
-	 */
-	down_read(&disk->lookup_sem);
-	if (unlikely((disk->flags & GENHD_FL_HIDDEN) ||
-		     !(disk->flags & GENHD_FL_UP))) {
-		up_read(&disk->lookup_sem);
-		put_disk_and_module(disk);
-		disk = NULL;
-	} else {
-		up_read(&disk->lookup_sem);
-	}
-	return disk;
-}
-
 /**
  * bdget_disk - do bdget() by gendisk and partition number
  * @disk: gendisk of interest
@@ -1559,11 +1411,6 @@ int disk_expand_part_tbl(struct gendisk *disk, int partno)
  *
  * This function releases all allocated resources of the gendisk.
  *
- * The struct gendisk refcount is incremented with get_gendisk() or
- * get_disk_and_module(), and its refcount is decremented with
- * put_disk_and_module() or put_disk(). Once the refcount reaches 0 this
- * function is called.
- *
  * Drivers which used __device_add_disk() have a gendisk with a request_queue
  * assigned. Since the request_queue sits on top of the gendisk for these
  * drivers we also call blk_put_queue() for them, and we expect the
@@ -1585,7 +1432,7 @@ static void disk_release(struct device *dev)
 	hd_free_part(&disk->part0);
 	if (disk->queue)
 		blk_put_queue(disk->queue);
-	kfree(disk);
+	kfree_rcu(disk, rcu);
 }
 struct class block_class = {
 	.name		= "block",
@@ -1748,16 +1595,17 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
 	if (!disk)
 		return NULL;
 
+	disk->part0.bdev = bdev_alloc(disk, 0);
+	if (!disk->part0.bdev)
+		goto out_free_disk;
+
 	disk->part0.dkstats = alloc_percpu(struct disk_stats);
 	if (!disk->part0.dkstats)
-		goto out_free_disk;
+		goto out_bdput;
 
-	init_rwsem(&disk->lookup_sem);
 	disk->node_id = node_id;
-	if (disk_expand_part_tbl(disk, 0)) {
-		free_percpu(disk->part0.dkstats);
-		goto out_free_disk;
-	}
+	if (disk_expand_part_tbl(disk, 0))
+		goto out_free_bdstats;
 
 	ptbl = rcu_dereference_protected(disk->part_tbl, 1);
 	rcu_assign_pointer(ptbl->part[0], &disk->part0);
@@ -1773,7 +1621,7 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
 	 */
 	hd_sects_seq_init(&disk->part0);
 	if (hd_ref_init(&disk->part0))
-		goto out_free_part0;
+		goto out_free_bdstats;
 
 	disk->minors = minors;
 	rand_initialize_disk(disk);
@@ -1782,8 +1630,10 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
 	device_initialize(disk_to_dev(disk));
 	return disk;
 
-out_free_part0:
-	hd_free_part(&disk->part0);
+out_free_bdstats:
+	free_percpu(disk->part0.dkstats);
+out_bdput:
+	bdput(disk->part0.bdev);
 out_free_disk:
 	kfree(disk);
 	return NULL;
@@ -1807,26 +1657,6 @@ void put_disk(struct gendisk *disk)
 }
 EXPORT_SYMBOL(put_disk);
 
-/**
- * put_disk_and_module - decrements the module and gendisk refcount
- * @disk: the struct gendisk to decrement the refcount for
- *
- * This is a counterpart of get_disk_and_module() and thus also of
- * get_gendisk().
- *
- * Context: Any context, but the last reference must not be dropped from
- *          atomic context.
- */
-void put_disk_and_module(struct gendisk *disk)
-{
-	if (disk) {
-		struct module *owner = disk->fops->owner;
-
-		put_disk(disk);
-		module_put(owner);
-	}
-}
-
 static void set_disk_ro_uevent(struct gendisk *gd, int ro)
 {
 	char event[] = "DISK_RO=1";
diff --git a/block/partitions/core.c b/block/partitions/core.c
index a02e224115943d..508b46da53eee5 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -340,12 +340,11 @@ void delete_partition(struct hd_struct *part)
 	device_del(part_to_dev(part));
 
 	/*
-	 * Remove gendisk pointer from idr so that it cannot be looked up
-	 * while RCU period before freeing gendisk is running to prevent
-	 * use-after-free issues. Note that the device number stays
-	 * "in-use" until we really free the gendisk.
+	 * Remove the block device from the inode hash, so that it cannot be
+	 * looked up while waiting for the RCU grace period.
 	 */
-	blk_invalidate_devt(part_devt(part));
+	remove_inode_hash(part->bdev->bd_inode);
+
 	percpu_ref_kill(&part->ref);
 }
 
@@ -368,6 +367,7 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 	dev_t devt = MKDEV(0, 0);
 	struct device *ddev = disk_to_dev(disk);
 	struct device *pdev;
+	struct block_device *bdev;
 	struct disk_part_tbl *ptbl;
 	const char *dname;
 	int err;
@@ -402,11 +402,15 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 	if (!p)
 		return ERR_PTR(-EBUSY);
 
+	err = -ENOMEM;
 	p->dkstats = alloc_percpu(struct disk_stats);
-	if (!p->dkstats) {
-		err = -ENOMEM;
+	if (!p->dkstats)
 		goto out_free;
-	}
+
+	bdev = bdev_alloc(disk, partno);
+	if (!bdev)
+		goto out_free_stats;
+	p->bdev = bdev;
 
 	hd_sects_seq_init(p);
 	pdev = part_to_dev(p);
@@ -420,10 +424,8 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 		struct partition_meta_info *pinfo;
 
 		pinfo = kzalloc_node(sizeof(*pinfo), GFP_KERNEL, disk->node_id);
-		if (!pinfo) {
-			err = -ENOMEM;
-			goto out_free_stats;
-		}
+		if (!pinfo)
+			goto out_bdput;
 		memcpy(pinfo, info, sizeof(*info));
 		p->info = pinfo;
 	}
@@ -470,6 +472,7 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 	}
 
 	/* everything is up and running, commence */
+	bdev_add(bdev, devt);
 	rcu_assign_pointer(ptbl->part[partno], p);
 
 	/* suppress uevent if the disk suppresses it */
@@ -479,6 +482,8 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 
 out_free_info:
 	kfree(p->info);
+out_bdput:
+	bdput(bdev);
 out_free_stats:
 	free_percpu(p->dkstats);
 out_free:
diff --git a/fs/block_dev.c b/fs/block_dev.c
index c0d1e8248ffe23..b9ee8fe5acd570 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -863,31 +863,45 @@ void __init bdev_cache_init(void)
 	blockdev_superblock = bd_mnt->mnt_sb;   /* For writeback */
 }
 
-static struct block_device *bdget(dev_t dev)
+struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
 {
 	struct block_device *bdev;
 	struct inode *inode;
 
-	inode = iget_locked(blockdev_superblock, dev);
+	inode = new_inode(blockdev_superblock);
 	if (!inode)
 		return NULL;
+	inode->i_mode = S_IFBLK;
+	inode->i_rdev = 0;
+	inode->i_data.a_ops = &def_blk_aops;
+
+	bdev = I_BDEV(inode);
+	spin_lock_init(&bdev->bd_size_lock);
+	bdev->bd_disk = disk;
+	bdev->bd_partno = partno;
+	bdev->bd_contains = NULL;
+	bdev->bd_super = NULL;
+	bdev->bd_inode = inode;
+	bdev->bd_part_count = 0;
+	return bdev;
+}
 
-	bdev = &BDEV_I(inode)->bdev;
+void bdev_add(struct block_device *bdev, dev_t dev)
+{
+	bdev->bd_dev = dev;
+	bdev->bd_inode->i_rdev = dev;
+	bdev->bd_inode->i_ino = dev;
+	insert_inode_hash(bdev->bd_inode);
+}
 
-	if (inode->i_state & I_NEW) {
-		spin_lock_init(&bdev->bd_size_lock);
-		bdev->bd_contains = NULL;
-		bdev->bd_super = NULL;
-		bdev->bd_inode = inode;
-		bdev->bd_part_count = 0;
-		bdev->bd_dev = dev;
-		inode->i_mode = S_IFBLK;
-		inode->i_rdev = dev;
-		inode->i_data.a_ops = &def_blk_aops;
-		mapping_set_gfp_mask(&inode->i_data, GFP_USER);
-		unlock_new_inode(inode);
-	}
-	return bdev;
+static struct block_device *bdget(dev_t dev)
+{
+	struct inode *inode;
+
+	inode = ilookup(blockdev_superblock, dev);
+	if (!inode)
+		return NULL;
+	return &BDEV_I(inode)->bdev;
 }
 
 /**
@@ -1000,27 +1014,6 @@ int bd_prepare_to_claim(struct block_device *bdev, struct block_device *whole,
 }
 EXPORT_SYMBOL_GPL(bd_prepare_to_claim); /* only for the loop driver */
 
-static struct gendisk *bdev_get_gendisk(struct block_device *bdev, int *partno)
-{
-	struct gendisk *disk = get_gendisk(bdev->bd_dev, partno);
-
-	if (!disk)
-		return NULL;
-	/*
-	 * Now that we hold gendisk reference we make sure bdev we looked up is
-	 * not stale. If it is, it means device got removed and created before
-	 * we looked up gendisk and we fail open in such case. Associating
-	 * unhashed bdev with newly created gendisk could lead to two bdevs
-	 * (and thus two independent caches) being associated with one device
-	 * which is bad.
-	 */
-	if (inode_unhashed(bdev->bd_inode)) {
-		put_disk_and_module(disk);
-		return NULL;
-	}
-	return disk;
-}
-
 static void bd_clear_claiming(struct block_device *whole, void *holder)
 {
 	lockdep_assert_held(&bdev_lock);
@@ -1343,19 +1336,17 @@ EXPORT_SYMBOL_GPL(bdev_disk_changed);
  *  mutex_lock(part->bd_mutex)
  *    mutex_lock_nested(whole->bd_mutex, 1)
  */
-static int __blkdev_get(struct block_device *bdev, struct gendisk *disk,
-		int partno, fmode_t mode)
+static int __blkdev_get(struct block_device *bdev, fmode_t mode)
 {
+	struct gendisk *disk = bdev->bd_disk;
 	int ret;
 
 	if (!bdev->bd_openers) {
-		bdev->bd_disk = disk;
 		bdev->bd_contains = bdev;
-		bdev->bd_partno = partno;
 
-		if (!partno) {
+		if (!bdev->bd_partno) {
 			ret = -ENXIO;
-			bdev->bd_part = disk_get_part(disk, partno);
+			bdev->bd_part = disk_get_part(disk, 0);
 			if (!bdev->bd_part)
 				goto out_clear;
 
@@ -1384,7 +1375,7 @@ static int __blkdev_get(struct block_device *bdev, struct gendisk *disk,
 			struct block_device *whole = bdget_disk(disk, 0);
 
 			mutex_lock_nested(&whole->bd_mutex, 1);
-			ret = __blkdev_get(whole, disk, 0, mode);
+			ret = __blkdev_get(whole, mode);
 			if (ret) {
 				mutex_unlock(&whole->bd_mutex);
 				bdput(whole);
@@ -1394,9 +1385,8 @@ static int __blkdev_get(struct block_device *bdev, struct gendisk *disk,
 			mutex_unlock(&whole->bd_mutex);
 
 			bdev->bd_contains = whole;
-			bdev->bd_part = disk_get_part(disk, partno);
-			if (!(disk->flags & GENHD_FL_UP) ||
-			    !bdev->bd_part || !bdev->bd_part->nr_sects) {
+			bdev->bd_part = disk_get_part(disk, bdev->bd_partno);
+			if (!bdev->bd_part || !bdev->bd_part->nr_sects) {
 				__blkdev_put(whole, mode, 1);
 				ret = -ENXIO;
 				goto out_clear;
@@ -1425,12 +1415,46 @@ static int __blkdev_get(struct block_device *bdev, struct gendisk *disk,
 
  out_clear:
 	disk_put_part(bdev->bd_part);
-	bdev->bd_disk = NULL;
 	bdev->bd_part = NULL;
 	bdev->bd_contains = NULL;
 	return ret;
 }
 
+static struct block_device *get_bdev_disk_and_module(dev_t dev)
+{
+	struct block_device *bdev = NULL;
+	struct gendisk *disk = NULL;
+
+	rcu_read_lock();
+	bdev = bdget(dev);
+	if (!bdev) {
+		rcu_read_unlock();
+		blk_request_module(dev);
+		rcu_read_lock();
+
+		bdev = bdget(dev);
+	}
+	if (!bdev)
+		goto fail;
+
+	if (!kobject_get_unless_zero(&disk_to_dev(bdev->bd_disk)->kobj))
+		goto fail;
+	disk = bdev->bd_disk;
+	if ((disk->flags & (GENHD_FL_UP | GENHD_FL_HIDDEN)) != GENHD_FL_UP)
+		goto fail;
+	if (!try_module_get(bdev->bd_disk->fops->owner))
+		goto fail;
+	rcu_read_unlock();
+	return bdev;
+fail:
+	rcu_read_unlock();
+	if (disk)
+		put_disk(disk);
+	if (bdev)
+		bdput(bdev);
+	return NULL;
+}
+
 /**
  * blkdev_get_by_dev - open a block device by device number
  * @dev: device number of block device to open
@@ -1458,7 +1482,6 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 	bool unblock_events = true;
 	struct block_device *bdev;
 	struct gendisk *disk;
-	int partno;
 	int ret;
 
 	ret = devcgroup_check_permission(DEVCG_DEV_BLOCK,
@@ -1468,19 +1491,15 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 	if (ret)
 		return ERR_PTR(ret);
 
-	bdev = bdget(dev);
-	if (!bdev)
-		return ERR_PTR(-ENOMEM);
-
 	/*
 	 * If we lost a race with 'disk' being deleted, try again.  See md.c.
 	 */
 retry:
-	ret = -ENXIO;
-	disk = bdev_get_gendisk(bdev, &partno);
-	if (!disk)
-		goto bdput;
-
+	bdev = get_bdev_disk_and_module(dev);
+	if (!bdev)
+		return ERR_PTR(-ENXIO);
+	disk = bdev->bd_disk;
+ 
 	if (mode & FMODE_EXCL) {
 		WARN_ON_ONCE(!holder);
 	
@@ -1496,12 +1515,10 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 	disk_block_events(disk);
 
 	mutex_lock(&bdev->bd_mutex);
-	ret =__blkdev_get(bdev, disk, partno, mode);
-	if (!(mode & FMODE_EXCL)) {
-		; /* nothing to do here */
-	} else if (ret) {
-		bd_abort_claiming(bdev, claiming, holder);
-	} else {
+	ret =__blkdev_get(bdev, mode);
+	if (ret)
+		goto abort_claiming;
+	if (mode & FMODE_EXCL) {
 		bd_finish_claiming(bdev, claiming, holder);
 
 		/*
@@ -1521,21 +1538,25 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 
 	if (unblock_events)
 		disk_unblock_events(disk);
+	if (mode & FMODE_EXCL)
+		bdput(claiming);
+	return bdev;
 
+abort_claiming:
+	if (mode & FMODE_EXCL)
+		bd_abort_claiming(bdev, claiming, holder);
+	mutex_unlock(&bdev->bd_mutex);
+	disk_unblock_events(disk);
 put_claiming:
 	if (mode & FMODE_EXCL)
 		bdput(claiming);
 put_disk:
-	if (ret)
-		put_disk_and_module(disk);
+	module_put(disk->fops->owner);
+	put_disk(disk);
+	bdput(bdev);
 	if (ret == -ERESTARTSYS)
 		goto retry;
-bdput:
-	if (ret) {
-		bdput(bdev);
-		return ERR_PTR(ret);
-	}
-	return bdev;
+	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL(blkdev_get_by_dev);
 
@@ -1637,7 +1658,6 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
 
 		disk_put_part(bdev->bd_part);
 		bdev->bd_part = NULL;
-		bdev->bd_disk = NULL;
 		if (bdev_is_partition(bdev))
 			victim = bdev->bd_contains;
 		bdev->bd_contains = NULL;
@@ -1698,7 +1718,8 @@ void blkdev_put(struct block_device *bdev, fmode_t mode)
 	mutex_unlock(&bdev->bd_mutex);
 
 	__blkdev_put(bdev, mode, 0);
-	put_disk_and_module(disk);
+	module_put(disk->fops->owner);
+	put_disk(disk);
 }
 EXPORT_SYMBOL(blkdev_put);
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index bdd7339bcda462..48e5a8393cd793 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1994,6 +1994,8 @@ void bd_abort_claiming(struct block_device *bdev, struct block_device *whole,
 		void *holder);
 void blkdev_put(struct block_device *bdev, fmode_t mode);
 
+struct block_device *bdev_alloc(struct gendisk *disk, u8 partno);
+void bdev_add(struct block_device *bdev, dev_t dev);
 struct block_device *I_BDEV(struct inode *inode);
 struct block_device *bdget_part(struct hd_struct *part);
 struct block_device *bdgrab(struct block_device *bdev);
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index ca5e356084c353..d068e46f9086ae 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -65,6 +65,7 @@ struct hd_struct {
 	struct disk_stats __percpu *dkstats;
 	struct percpu_ref ref;
 
+	struct block_device *bdev;
 	struct device __dev;
 	struct kobject *holder_dir;
 	int policy, partno;
@@ -193,7 +194,6 @@ struct gendisk {
 	int flags;
 	unsigned long state;
 #define GD_NEED_PART_SCAN		0
-	struct rw_semaphore lookup_sem;
 	struct kobject *slave_dir;
 
 	struct timer_rand_state *random;
@@ -207,6 +207,7 @@ struct gendisk {
 #endif
 	int node_id;
 	struct badblocks *bb;
+	struct rcu_head rcu;
 	struct lockdep_map lockdep_map;
 };
 
@@ -300,7 +301,6 @@ static inline void add_disk_no_queue_reg(struct gendisk *disk)
 }
 
 extern void del_gendisk(struct gendisk *gp);
-extern struct gendisk *get_gendisk(dev_t dev, int *partno);
 extern struct block_device *bdget_disk(struct gendisk *disk, int partno);
 
 extern void set_disk_ro(struct gendisk *disk, int flag);
@@ -338,7 +338,6 @@ int blk_drop_partitions(struct block_device *bdev);
 
 extern struct gendisk *__alloc_disk_node(int minors, int node_id);
 extern void put_disk(struct gendisk *disk);
-extern void put_disk_and_module(struct gendisk *disk);
 
 #define alloc_disk_node(minors, node_id)				\
 ({									\
@@ -389,6 +388,7 @@ static inline void bd_unlink_disk_holder(struct block_device *bdev,
 #endif /* CONFIG_SYSFS */
 
 dev_t blk_lookup_devt(const char *name, int partno);
+void blk_request_module(dev_t devt);
 #ifdef CONFIG_BLOCK
 void printk_all_partitions(void);
 #else /* CONFIG_BLOCK */
-- 
2.29.2

--
dm-devel mailing list
dm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel


^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 26/45] block: remove ->bd_contains
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (24 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 25/45] block: reference struct block_device from struct hd_struct Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 21:19   ` Tejun Heo
  2020-11-24 13:27 ` [dm-devel] [PATCH 27/45] block: simplify the block device claiming interface Christoph Hellwig
                   ` (18 subsequent siblings)
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Now that each hd_struct has a reference to the corresponding
block_device, there is no need for the bd_contains pointer.  Add
a bdev_whole() helper to look up the whole device block_device
struture instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 drivers/block/loop.c      |  2 +-
 drivers/scsi/scsicam.c    |  2 +-
 fs/block_dev.c            | 22 ++++++++--------------
 include/linux/blk_types.h |  4 +++-
 4 files changed, 13 insertions(+), 17 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 26c7aafba7c5f8..c0df88b3300c41 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1088,7 +1088,7 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
 	 * here to avoid changing device under exclusive owner.
 	 */
 	if (!(mode & FMODE_EXCL)) {
-		claimed_bdev = bdev->bd_contains;
+		claimed_bdev = bdev_whole(bdev);
 		error = bd_prepare_to_claim(bdev, claimed_bdev, loop_configure);
 		if (error)
 			goto out_putf;
diff --git a/drivers/scsi/scsicam.c b/drivers/scsi/scsicam.c
index 682cf08ab04153..f1553a453616fd 100644
--- a/drivers/scsi/scsicam.c
+++ b/drivers/scsi/scsicam.c
@@ -32,7 +32,7 @@
  */
 unsigned char *scsi_bios_ptable(struct block_device *dev)
 {
-	struct address_space *mapping = dev->bd_contains->bd_inode->i_mapping;
+	struct address_space *mapping = bdev_whole(dev)->bd_inode->i_mapping;
 	unsigned char *res = NULL;
 	struct page *page;
 
diff --git a/fs/block_dev.c b/fs/block_dev.c
index b9ee8fe5acd570..e8d7de5fae00a9 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -119,7 +119,7 @@ int truncate_bdev_range(struct block_device *bdev, fmode_t mode,
 	 * under live filesystem.
 	 */
 	if (!(mode & FMODE_EXCL)) {
-		claimed_bdev = bdev->bd_contains;
+		claimed_bdev = bdev_whole(bdev);
 		err = bd_prepare_to_claim(bdev, claimed_bdev,
 					  truncate_bdev_range);
 		if (err)
@@ -879,7 +879,6 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
 	spin_lock_init(&bdev->bd_size_lock);
 	bdev->bd_disk = disk;
 	bdev->bd_partno = partno;
-	bdev->bd_contains = NULL;
 	bdev->bd_super = NULL;
 	bdev->bd_inode = inode;
 	bdev->bd_part_count = 0;
@@ -1342,9 +1341,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode)
 	int ret;
 
 	if (!bdev->bd_openers) {
-		bdev->bd_contains = bdev;
-
-		if (!bdev->bd_partno) {
+		if (!bdev_is_partition(bdev)) {
 			ret = -ENXIO;
 			bdev->bd_part = disk_get_part(disk, 0);
 			if (!bdev->bd_part)
@@ -1384,7 +1381,6 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode)
 			whole->bd_part_count++;
 			mutex_unlock(&whole->bd_mutex);
 
-			bdev->bd_contains = whole;
 			bdev->bd_part = disk_get_part(disk, bdev->bd_partno);
 			if (!bdev->bd_part || !bdev->bd_part->nr_sects) {
 				__blkdev_put(whole, mode, 1);
@@ -1398,7 +1394,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode)
 		if (bdev->bd_bdi == &noop_backing_dev_info)
 			bdev->bd_bdi = bdi_get(disk->queue->backing_dev_info);
 	} else {
-		if (bdev->bd_contains == bdev) {
+		if (!bdev_is_partition(bdev)) {
 			ret = 0;
 			if (bdev->bd_disk->fops->open)
 				ret = bdev->bd_disk->fops->open(bdev, mode);
@@ -1416,7 +1412,6 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode)
  out_clear:
 	disk_put_part(bdev->bd_part);
 	bdev->bd_part = NULL;
-	bdev->bd_contains = NULL;
 	return ret;
 }
 
@@ -1659,8 +1654,7 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
 		disk_put_part(bdev->bd_part);
 		bdev->bd_part = NULL;
 		if (bdev_is_partition(bdev))
-			victim = bdev->bd_contains;
-		bdev->bd_contains = NULL;
+			victim = bdev_whole(bdev);
 	} else {
 		if (!bdev_is_partition(bdev) && disk->fops->release)
 			disk->fops->release(disk, mode);
@@ -1678,6 +1672,7 @@ void blkdev_put(struct block_device *bdev, fmode_t mode)
 	mutex_lock(&bdev->bd_mutex);
 
 	if (mode & FMODE_EXCL) {
+		struct block_device *whole = bdev_whole(bdev);
 		bool bdev_free;
 
 		/*
@@ -1688,13 +1683,12 @@ void blkdev_put(struct block_device *bdev, fmode_t mode)
 		spin_lock(&bdev_lock);
 
 		WARN_ON_ONCE(--bdev->bd_holders < 0);
-		WARN_ON_ONCE(--bdev->bd_contains->bd_holders < 0);
+		WARN_ON_ONCE(--whole->bd_holders < 0);
 
-		/* bd_contains might point to self, check in a separate step */
 		if ((bdev_free = !bdev->bd_holders))
 			bdev->bd_holder = NULL;
-		if (!bdev->bd_contains->bd_holders)
-			bdev->bd_contains->bd_holder = NULL;
+		if (!whole->bd_holders)
+			whole->bd_holder = NULL;
 
 		spin_unlock(&bdev_lock);
 
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 9698f459cc65c9..2e0a9bd9688d28 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -32,7 +32,6 @@ struct block_device {
 #ifdef CONFIG_SYSFS
 	struct list_head	bd_holder_disks;
 #endif
-	struct block_device *	bd_contains;
 	u8			bd_partno;
 	struct hd_struct *	bd_part;
 	/* number of times partitions within this device have been opened. */
@@ -49,6 +48,9 @@ struct block_device {
 	struct super_block	*bd_fsfreeze_sb;
 } __randomize_layout;
 
+#define bdev_whole(_bdev) \
+	((_bdev)->bd_disk->part0.bdev)
+
 #define bdev_kobj(_bdev) \
 	(&part_to_dev((_bdev)->bd_part)->kobj)
 
-- 
2.29.2

--
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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 27/45] block: simplify the block device claiming interface
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (25 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 26/45] block: remove ->bd_contains Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 21:19   ` Tejun Heo
  2020-11-24 13:27 ` [dm-devel] [PATCH 28/45] block: simplify part_to_disk Christoph Hellwig
                   ` (17 subsequent siblings)
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Stop passing the whole device as a separate argument given that it
can be trivially deducted and cleanup the !holder debug check.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 drivers/block/loop.c   | 12 +++++-----
 fs/block_dev.c         | 51 +++++++++++++++---------------------------
 include/linux/blkdev.h |  6 ++---
 3 files changed, 25 insertions(+), 44 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index c0df88b3300c41..d643c67be6acea 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1069,7 +1069,6 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
 	struct file	*file;
 	struct inode	*inode;
 	struct address_space *mapping;
-	struct block_device *claimed_bdev = NULL;
 	int		error;
 	loff_t		size;
 	bool		partscan;
@@ -1088,8 +1087,7 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
 	 * here to avoid changing device under exclusive owner.
 	 */
 	if (!(mode & FMODE_EXCL)) {
-		claimed_bdev = bdev_whole(bdev);
-		error = bd_prepare_to_claim(bdev, claimed_bdev, loop_configure);
+		error = bd_prepare_to_claim(bdev, loop_configure);
 		if (error)
 			goto out_putf;
 	}
@@ -1176,15 +1174,15 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
 	mutex_unlock(&loop_ctl_mutex);
 	if (partscan)
 		loop_reread_partitions(lo, bdev);
-	if (claimed_bdev)
-		bd_abort_claiming(bdev, claimed_bdev, loop_configure);
+	if (!(mode & FMODE_EXCL))
+		bd_abort_claiming(bdev, loop_configure);
 	return 0;
 
 out_unlock:
 	mutex_unlock(&loop_ctl_mutex);
 out_bdev:
-	if (claimed_bdev)
-		bd_abort_claiming(bdev, claimed_bdev, loop_configure);
+	if (!(mode & FMODE_EXCL))
+		bd_abort_claiming(bdev, loop_configure);
 out_putf:
 	fput(file);
 out:
diff --git a/fs/block_dev.c b/fs/block_dev.c
index e8d7de5fae00a9..43a0fda982c879 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -110,24 +110,20 @@ EXPORT_SYMBOL(invalidate_bdev);
 int truncate_bdev_range(struct block_device *bdev, fmode_t mode,
 			loff_t lstart, loff_t lend)
 {
-	struct block_device *claimed_bdev = NULL;
-	int err;
-
 	/*
 	 * If we don't hold exclusive handle for the device, upgrade to it
 	 * while we discard the buffer cache to avoid discarding buffers
 	 * under live filesystem.
 	 */
 	if (!(mode & FMODE_EXCL)) {
-		claimed_bdev = bdev_whole(bdev);
-		err = bd_prepare_to_claim(bdev, claimed_bdev,
-					  truncate_bdev_range);
+		int err = bd_prepare_to_claim(bdev, truncate_bdev_range);
 		if (err)
 			return err;
 	}
+
 	truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend);
-	if (claimed_bdev)
-		bd_abort_claiming(bdev, claimed_bdev, truncate_bdev_range);
+	if (!(mode & FMODE_EXCL))
+		bd_abort_claiming(bdev, truncate_bdev_range);
 	return 0;
 }
 EXPORT_SYMBOL(truncate_bdev_range);
@@ -973,7 +969,6 @@ static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
 /**
  * bd_prepare_to_claim - claim a block device
  * @bdev: block device of interest
- * @whole: the whole device containing @bdev, may equal @bdev
  * @holder: holder trying to claim @bdev
  *
  * Claim @bdev.  This function fails if @bdev is already claimed by another
@@ -983,9 +978,12 @@ static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
  * RETURNS:
  * 0 if @bdev can be claimed, -EBUSY otherwise.
  */
-int bd_prepare_to_claim(struct block_device *bdev, struct block_device *whole,
-		void *holder)
+int bd_prepare_to_claim(struct block_device *bdev, void *holder)
 {
+	struct block_device *whole = bdev_whole(bdev);
+
+	if (WARN_ON_ONCE(!holder))
+		return -EINVAL;
 retry:
 	spin_lock(&bdev_lock);
 	/* if someone else claimed, fail */
@@ -1025,15 +1023,15 @@ static void bd_clear_claiming(struct block_device *whole, void *holder)
 /**
  * bd_finish_claiming - finish claiming of a block device
  * @bdev: block device of interest
- * @whole: whole block device
  * @holder: holder that has claimed @bdev
  *
  * Finish exclusive open of a block device. Mark the device as exlusively
  * open by the holder and wake up all waiters for exclusive open to finish.
  */
-static void bd_finish_claiming(struct block_device *bdev,
-		struct block_device *whole, void *holder)
+static void bd_finish_claiming(struct block_device *bdev, void *holder)
 {
+	struct block_device *whole = bdev_whole(bdev);
+
 	spin_lock(&bdev_lock);
 	BUG_ON(!bd_may_claim(bdev, whole, holder));
 	/*
@@ -1058,11 +1056,10 @@ static void bd_finish_claiming(struct block_device *bdev,
  * also used when exclusive open is not actually desired and we just needed
  * to block other exclusive openers for a while.
  */
-void bd_abort_claiming(struct block_device *bdev, struct block_device *whole,
-		       void *holder)
+void bd_abort_claiming(struct block_device *bdev, void *holder)
 {
 	spin_lock(&bdev_lock);
-	bd_clear_claiming(whole, holder);
+	bd_clear_claiming(bdev_whole(bdev), holder);
 	spin_unlock(&bdev_lock);
 }
 EXPORT_SYMBOL(bd_abort_claiming);
@@ -1473,7 +1470,6 @@ static struct block_device *get_bdev_disk_and_module(dev_t dev)
  */
 struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 {
-	struct block_device *claiming;
 	bool unblock_events = true;
 	struct block_device *bdev;
 	struct gendisk *disk;
@@ -1496,15 +1492,9 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 	disk = bdev->bd_disk;
  
 	if (mode & FMODE_EXCL) {
-		WARN_ON_ONCE(!holder);
-	
-		ret = -ENOMEM;
-		claiming = bdget_disk(disk, 0);
-		if (!claiming)
-			goto put_disk;
-		ret = bd_prepare_to_claim(bdev, claiming, holder);
+		ret = bd_prepare_to_claim(bdev, holder);
 		if (ret)
-			goto put_claiming;
+			goto put_disk;
 	}
 
 	disk_block_events(disk);
@@ -1514,7 +1504,7 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 	if (ret)
 		goto abort_claiming;
 	if (mode & FMODE_EXCL) {
-		bd_finish_claiming(bdev, claiming, holder);
+		bd_finish_claiming(bdev, holder);
 
 		/*
 		 * Block event polling for write claims if requested.  Any write
@@ -1533,18 +1523,13 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 
 	if (unblock_events)
 		disk_unblock_events(disk);
-	if (mode & FMODE_EXCL)
-		bdput(claiming);
 	return bdev;
 
 abort_claiming:
 	if (mode & FMODE_EXCL)
-		bd_abort_claiming(bdev, claiming, holder);
+		bd_abort_claiming(bdev, holder);
 	mutex_unlock(&bdev->bd_mutex);
 	disk_unblock_events(disk);
-put_claiming:
-	if (mode & FMODE_EXCL)
-		bdput(claiming);
 put_disk:
 	module_put(disk->fops->owner);
 	put_disk(disk);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 48e5a8393cd793..db1b11d6d07568 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1988,10 +1988,8 @@ void blkdev_show(struct seq_file *seqf, off_t offset);
 struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
 		void *holder);
 struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder);
-int bd_prepare_to_claim(struct block_device *bdev, struct block_device *whole,
-		void *holder);
-void bd_abort_claiming(struct block_device *bdev, struct block_device *whole,
-		void *holder);
+int bd_prepare_to_claim(struct block_device *bdev, void *holder);
+void bd_abort_claiming(struct block_device *bdev, void *holder);
 void blkdev_put(struct block_device *bdev, fmode_t mode);
 
 struct block_device *bdev_alloc(struct gendisk *disk, u8 partno);
-- 
2.29.2

--
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https://www.redhat.com/mailman/listinfo/dm-devel


^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 28/45] block: simplify part_to_disk
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (26 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 27/45] block: simplify the block device claiming interface Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 21:20   ` Tejun Heo
  2020-11-24 13:27 ` [dm-devel] [PATCH 29/45] block: initialize struct block_device in bdev_alloc Christoph Hellwig
                   ` (16 subsequent siblings)
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Now that struct hd_struct has a block_device pointer use that to
find the disk.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 include/linux/genhd.h | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index d068e46f9086ae..dcf86a3d4dedc4 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -219,13 +219,9 @@ struct gendisk {
 
 static inline struct gendisk *part_to_disk(struct hd_struct *part)
 {
-	if (likely(part)) {
-		if (part->partno)
-			return dev_to_disk(part_to_dev(part)->parent);
-		else
-			return dev_to_disk(part_to_dev(part));
-	}
-	return NULL;
+	if (unlikely(!part))
+		return NULL;
+	return part->bdev->bd_disk;
 }
 
 static inline int disk_max_parts(struct gendisk *disk)
-- 
2.29.2

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 29/45] block: initialize struct block_device in bdev_alloc
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (27 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 28/45] block: simplify part_to_disk Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 21:20   ` Tejun Heo
  2020-11-24 13:27 ` [dm-devel] [PATCH 30/45] block: remove the nr_sects field in struct hd_struct Christoph Hellwig
                   ` (15 subsequent siblings)
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Don't play tricks with slab constructors as bdev structures tends to not
get reused very much, and this makes the code a lot less error prone.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/block_dev.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 43a0fda982c879..1e5c6d0eb92677 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -784,20 +784,11 @@ static void bdev_free_inode(struct inode *inode)
 	kmem_cache_free(bdev_cachep, BDEV_I(inode));
 }
 
-static void init_once(void *foo)
+static void init_once(void *data)
 {
-	struct bdev_inode *ei = (struct bdev_inode *) foo;
-	struct block_device *bdev = &ei->bdev;
+	struct bdev_inode *ei = data;
 
-	memset(bdev, 0, sizeof(*bdev));
-	mutex_init(&bdev->bd_mutex);
-#ifdef CONFIG_SYSFS
-	INIT_LIST_HEAD(&bdev->bd_holder_disks);
-#endif
-	bdev->bd_bdi = &noop_backing_dev_info;
 	inode_init_once(&ei->vfs_inode);
-	/* Initialize mutex for freeze. */
-	mutex_init(&bdev->bd_fsfreeze_mutex);
 }
 
 static void bdev_evict_inode(struct inode *inode)
@@ -872,12 +863,17 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
 	inode->i_data.a_ops = &def_blk_aops;
 
 	bdev = I_BDEV(inode);
+	memset(bdev, 0, sizeof(*bdev));
+	mutex_init(&bdev->bd_mutex);
+	mutex_init(&bdev->bd_fsfreeze_mutex);
 	spin_lock_init(&bdev->bd_size_lock);
 	bdev->bd_disk = disk;
 	bdev->bd_partno = partno;
-	bdev->bd_super = NULL;
 	bdev->bd_inode = inode;
-	bdev->bd_part_count = 0;
+	bdev->bd_bdi = &noop_backing_dev_info;
+#ifdef CONFIG_SYSFS
+	INIT_LIST_HEAD(&bdev->bd_holder_disks);
+#endif
 	return bdev;
 }
 
-- 
2.29.2

--
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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 30/45] block: remove the nr_sects field in struct hd_struct
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (28 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 29/45] block: initialize struct block_device in bdev_alloc Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 13:34   ` Coly Li
  2020-11-25  6:10   ` Chao Yu
  2020-11-24 13:27 ` [dm-devel] [PATCH 31/45] block: move disk stat accounting to struct block_device Christoph Hellwig
                   ` (14 subsequent siblings)
  44 siblings, 2 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Now that the hd_struct always has a block device attached to it, there is
no need for having two size field that just get out of sync.

Additional the field in hd_struct did not use proper serializiation,
possibly allowing for torn writes.  By only using the block_device field
this problem also gets fixed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 block/bio.c                        |  4 +-
 block/blk-core.c                   |  2 +-
 block/blk.h                        | 53 ----------------------
 block/genhd.c                      | 55 +++++++++++-----------
 block/partitions/core.c            | 17 ++++---
 drivers/block/loop.c               |  1 -
 drivers/block/nbd.c                |  2 +-
 drivers/block/xen-blkback/common.h |  4 +-
 drivers/md/bcache/super.c          |  2 +-
 drivers/s390/block/dasd_ioctl.c    |  4 +-
 drivers/target/target_core_pscsi.c |  7 +--
 fs/block_dev.c                     | 73 +-----------------------------
 fs/f2fs/super.c                    |  2 +-
 fs/pstore/blk.c                    |  2 +-
 include/linux/genhd.h              | 29 +++---------
 kernel/trace/blktrace.c            |  2 +-
 16 files changed, 60 insertions(+), 199 deletions(-)

diff --git a/block/bio.c b/block/bio.c
index fa01bef35bb1fe..669bb47a31988e 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -613,8 +613,8 @@ void guard_bio_eod(struct bio *bio)
 	rcu_read_lock();
 	part = __disk_get_part(bio->bi_disk, bio->bi_partno);
 	if (part)
-		maxsector = part_nr_sects_read(part);
-	else
+		maxsector = bdev_nr_sectors(part->bdev);
+	else	
 		maxsector = get_capacity(bio->bi_disk);
 	rcu_read_unlock();
 
diff --git a/block/blk-core.c b/block/blk-core.c
index 2db8bda43b6e6d..988f45094a387b 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -755,7 +755,7 @@ static inline int blk_partition_remap(struct bio *bio)
 		goto out;
 
 	if (bio_sectors(bio)) {
-		if (bio_check_eod(bio, part_nr_sects_read(p)))
+		if (bio_check_eod(bio, bdev_nr_sectors(p->bdev)))
 			goto out;
 		bio->bi_iter.bi_sector += p->start_sect;
 		trace_block_bio_remap(bio->bi_disk->queue, bio, part_devt(p),
diff --git a/block/blk.h b/block/blk.h
index c4839abcfa27eb..09cee7024fb43e 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -387,59 +387,6 @@ static inline void hd_free_part(struct hd_struct *part)
 	percpu_ref_exit(&part->ref);
 }
 
-/*
- * Any access of part->nr_sects which is not protected by partition
- * bd_mutex or gendisk bdev bd_mutex, should be done using this
- * accessor function.
- *
- * Code written along the lines of i_size_read() and i_size_write().
- * CONFIG_PREEMPTION case optimizes the case of UP kernel with preemption
- * on.
- */
-static inline sector_t part_nr_sects_read(struct hd_struct *part)
-{
-#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
-	sector_t nr_sects;
-	unsigned seq;
-	do {
-		seq = read_seqcount_begin(&part->nr_sects_seq);
-		nr_sects = part->nr_sects;
-	} while (read_seqcount_retry(&part->nr_sects_seq, seq));
-	return nr_sects;
-#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
-	sector_t nr_sects;
-
-	preempt_disable();
-	nr_sects = part->nr_sects;
-	preempt_enable();
-	return nr_sects;
-#else
-	return part->nr_sects;
-#endif
-}
-
-/*
- * Should be called with mutex lock held (typically bd_mutex) of partition
- * to provide mutual exlusion among writers otherwise seqcount might be
- * left in wrong state leaving the readers spinning infinitely.
- */
-static inline void part_nr_sects_write(struct hd_struct *part, sector_t size)
-{
-#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
-	preempt_disable();
-	write_seqcount_begin(&part->nr_sects_seq);
-	part->nr_sects = size;
-	write_seqcount_end(&part->nr_sects_seq);
-	preempt_enable();
-#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
-	preempt_disable();
-	part->nr_sects = size;
-	preempt_enable();
-#else
-	part->nr_sects = size;
-#endif
-}
-
 int bio_add_hw_page(struct request_queue *q, struct bio *bio,
 		struct page *page, unsigned int len, unsigned int offset,
 		unsigned int max_sectors, bool *same_page);
diff --git a/block/genhd.c b/block/genhd.c
index 16c6b13242105b..8ace0628ac20b7 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -38,6 +38,16 @@ static void disk_add_events(struct gendisk *disk);
 static void disk_del_events(struct gendisk *disk);
 static void disk_release_events(struct gendisk *disk);
 
+void set_capacity(struct gendisk *disk, sector_t sectors)
+{
+	struct block_device *bdev = disk->part0.bdev;
+
+	spin_lock(&bdev->bd_size_lock);
+	i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT);
+	spin_unlock(&bdev->bd_size_lock);
+}
+EXPORT_SYMBOL(set_capacity);
+
 /*
  * Set disk capacity and notify if the size is not currently zero and will not
  * be set to zero.  Returns true if a uevent was sent, otherwise false.
@@ -45,18 +55,22 @@ static void disk_release_events(struct gendisk *disk);
 bool set_capacity_and_notify(struct gendisk *disk, sector_t size)
 {
 	sector_t capacity = get_capacity(disk);
+	char *envp[] = { "RESIZE=1", NULL };
 
 	set_capacity(disk, size);
-	revalidate_disk_size(disk, true);
-
-	if (capacity != size && capacity != 0 && size != 0) {
-		char *envp[] = { "RESIZE=1", NULL };
-
-		kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);
-		return true;
-	}
 
-	return false;
+	/*
+	 * Only print a message and send a uevent if the gendisk is user visible
+	 * and alive.  This avoids spamming the log and udev when setting the
+	 * initial capacity during probing.
+	 */
+	if (size == capacity ||
+	    (disk->flags & (GENHD_FL_UP | GENHD_FL_HIDDEN)) != GENHD_FL_UP)
+		return false;
+	pr_info("%s: detected capacity change from %lld to %lld\n",
+		disk->disk_name, size, capacity);
+	kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);
+	return true;
 }
 EXPORT_SYMBOL_GPL(set_capacity_and_notify);
 
@@ -245,7 +259,7 @@ struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter)
 		part = rcu_dereference(ptbl->part[piter->idx]);
 		if (!part)
 			continue;
-		if (!part_nr_sects_read(part) &&
+		if (!bdev_nr_sectors(part->bdev) &&
 		    !(piter->flags & DISK_PITER_INCL_EMPTY) &&
 		    !(piter->flags & DISK_PITER_INCL_EMPTY_PART0 &&
 		      piter->idx == 0))
@@ -282,7 +296,7 @@ EXPORT_SYMBOL_GPL(disk_part_iter_exit);
 static inline int sector_in_part(struct hd_struct *part, sector_t sector)
 {
 	return part->start_sect <= sector &&
-		sector < part->start_sect + part_nr_sects_read(part);
+		sector < part->start_sect + bdev_nr_sectors(part->bdev);
 }
 
 /**
@@ -978,8 +992,8 @@ void __init printk_all_partitions(void)
 
 			printk("%s%s %10llu %s %s", is_part0 ? "" : "  ",
 			       bdevt_str(part_devt(part), devt_buf),
-			       (unsigned long long)part_nr_sects_read(part) >> 1
-			       , disk_name(disk, part->partno, name_buf),
+			       bdev_nr_sectors(part->bdev) >> 1,
+			       disk_name(disk, part->partno, name_buf),
 			       part->info ? part->info->uuid : "");
 			if (is_part0) {
 				if (dev->parent && dev->parent->driver)
@@ -1071,7 +1085,7 @@ static int show_partition(struct seq_file *seqf, void *v)
 	while ((part = disk_part_iter_next(&piter)))
 		seq_printf(seqf, "%4d  %7d %10llu %s\n",
 			   MAJOR(part_devt(part)), MINOR(part_devt(part)),
-			   (unsigned long long)part_nr_sects_read(part) >> 1,
+			   bdev_nr_sectors(part->bdev) >> 1,
 			   disk_name(sgp, part->partno, buf));
 	disk_part_iter_exit(&piter);
 
@@ -1153,8 +1167,7 @@ ssize_t part_size_show(struct device *dev,
 {
 	struct hd_struct *p = dev_to_part(dev);
 
-	return sprintf(buf, "%llu\n",
-		(unsigned long long)part_nr_sects_read(p));
+	return sprintf(buf, "%llu\n", bdev_nr_sectors(p->bdev));
 }
 
 ssize_t part_stat_show(struct device *dev,
@@ -1610,16 +1623,6 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
 	ptbl = rcu_dereference_protected(disk->part_tbl, 1);
 	rcu_assign_pointer(ptbl->part[0], &disk->part0);
 
-	/*
-	 * set_capacity() and get_capacity() currently don't use
-	 * seqcounter to read/update the part0->nr_sects. Still init
-	 * the counter as we can read the sectors in IO submission
-	 * patch using seqence counters.
-	 *
-	 * TODO: Ideally set_capacity() and get_capacity() should be
-	 * converted to make use of bd_mutex and sequence counters.
-	 */
-	hd_sects_seq_init(&disk->part0);
 	if (hd_ref_init(&disk->part0))
 		goto out_free_bdstats;
 
diff --git a/block/partitions/core.c b/block/partitions/core.c
index 508b46da53eee5..92ffa55bdfddfd 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -85,6 +85,13 @@ static int (*check_part[])(struct parsed_partitions *) = {
 	NULL
 };
 
+static void bdev_set_nr_sectors(struct block_device *bdev, sector_t sectors)
+{
+	spin_lock(&bdev->bd_size_lock);
+	i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT);
+	spin_unlock(&bdev->bd_size_lock);
+}
+
 static struct parsed_partitions *allocate_partitions(struct gendisk *hd)
 {
 	struct parsed_partitions *state;
@@ -295,7 +302,7 @@ static void hd_struct_free_work(struct work_struct *work)
 	put_device(disk_to_dev(disk));
 
 	part->start_sect = 0;
-	part->nr_sects = 0;
+	bdev_set_nr_sectors(part->bdev, 0);
 	part_stat_set_all(part, 0);
 	put_device(part_to_dev(part));
 }
@@ -412,11 +419,10 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 		goto out_free_stats;
 	p->bdev = bdev;
 
-	hd_sects_seq_init(p);
 	pdev = part_to_dev(p);
 
 	p->start_sect = start;
-	p->nr_sects = len;
+	bdev_set_nr_sectors(bdev, len);
 	p->partno = partno;
 	p->policy = get_disk_ro(disk);
 
@@ -509,7 +515,7 @@ static bool partition_overlaps(struct gendisk *disk, sector_t start,
 	disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
 	while ((part = disk_part_iter_next(&piter))) {
 		if (part->partno == skip_partno ||
-		    start >= part->start_sect + part->nr_sects ||
+		    start >= part->start_sect + bdev_nr_sectors(part->bdev) ||
 		    start + length <= part->start_sect)
 			continue;
 		overlap = true;
@@ -600,8 +606,7 @@ int bdev_resize_partition(struct block_device *bdev, int partno,
 	if (partition_overlaps(bdev->bd_disk, start, length, partno))
 		goto out_unlock;
 
-	part_nr_sects_write(part, length);
-	bd_set_nr_sectors(bdevp, length);
+	bdev_set_nr_sectors(bdevp, length);
 
 	ret = 0;
 out_unlock:
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index d643c67be6acea..d2ce1ddc192d78 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1241,7 +1241,6 @@ static int __loop_clr_fd(struct loop_device *lo, bool release)
 	set_capacity(lo->lo_disk, 0);
 	loop_sysfs_exit(lo);
 	if (bdev) {
-		bd_set_nr_sectors(bdev, 0);
 		/* let user-space know about this change */
 		kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE);
 	}
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 45b0423ef2c53d..014683968ce174 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -1132,7 +1132,7 @@ static void nbd_bdev_reset(struct block_device *bdev)
 {
 	if (bdev->bd_openers > 1)
 		return;
-	bd_set_nr_sectors(bdev, 0);
+	set_capacity(bdev->bd_disk, 0);
 }
 
 static void nbd_parse_flags(struct nbd_device *nbd)
diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h
index c6ea5d38c509a6..0762db247b41b3 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -358,9 +358,7 @@ struct pending_req {
 };
 
 
-#define vbd_sz(_v)	((_v)->bdev->bd_part ? \
-			 (_v)->bdev->bd_part->nr_sects : \
-			  get_capacity((_v)->bdev->bd_disk))
+#define vbd_sz(_v)	bdev_nr_sectors((_v)->bdev)
 
 #define xen_blkif_get(_b) (atomic_inc(&(_b)->refcnt))
 #define xen_blkif_put(_b)				\
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index c55d3c58a7ef55..04fa40868fbe10 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1408,7 +1408,7 @@ static int cached_dev_init(struct cached_dev *dc, unsigned int block_size)
 			q->limits.raid_partial_stripes_expensive;
 
 	ret = bcache_device_init(&dc->disk, block_size,
-			 dc->bdev->bd_part->nr_sects - dc->sb.data_offset,
+			 bdev_nr_sectors(dc->bdev) - dc->sb.data_offset,
 			 dc->bdev, &bcache_cached_ops);
 	if (ret)
 		return ret;
diff --git a/drivers/s390/block/dasd_ioctl.c b/drivers/s390/block/dasd_ioctl.c
index 3359559517bfcf..304eba1acf163c 100644
--- a/drivers/s390/block/dasd_ioctl.c
+++ b/drivers/s390/block/dasd_ioctl.c
@@ -54,8 +54,6 @@ dasd_ioctl_enable(struct block_device *bdev)
 		return -ENODEV;
 
 	dasd_enable_device(base);
-	/* Formatting the dasd device can change the capacity. */
-	bd_set_nr_sectors(bdev, get_capacity(base->block->gdp));
 	dasd_put_device(base);
 	return 0;
 }
@@ -88,7 +86,7 @@ dasd_ioctl_disable(struct block_device *bdev)
 	 * Set i_size to zero, since read, write, etc. check against this
 	 * value.
 	 */
-	bd_set_nr_sectors(bdev, 0);
+	set_capacity(bdev->bd_disk, 0);
 	dasd_put_device(base);
 	return 0;
 }
diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c
index 4e37fa9b409d52..a70c33c49f0960 100644
--- a/drivers/target/target_core_pscsi.c
+++ b/drivers/target/target_core_pscsi.c
@@ -1027,12 +1027,7 @@ static u32 pscsi_get_device_type(struct se_device *dev)
 
 static sector_t pscsi_get_blocks(struct se_device *dev)
 {
-	struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);
-
-	if (pdv->pdv_bd && pdv->pdv_bd->bd_part)
-		return pdv->pdv_bd->bd_part->nr_sects;
-
-	return 0;
+	return bdev_nr_sectors(PSCSI_DEV(dev)->pdv_bd);
 }
 
 static void pscsi_req_done(struct request *req, blk_status_t status)
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 1e5c6d0eb92677..02536d9fa29945 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1203,70 +1203,6 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
 EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
 #endif
 
-/**
- * check_disk_size_change - checks for disk size change and adjusts bdev size.
- * @disk: struct gendisk to check
- * @bdev: struct bdev to adjust.
- * @verbose: if %true log a message about a size change if there is any
- *
- * This routine checks to see if the bdev size does not match the disk size
- * and adjusts it if it differs. When shrinking the bdev size, its all caches
- * are freed.
- */
-static void check_disk_size_change(struct gendisk *disk,
-		struct block_device *bdev, bool verbose)
-{
-	loff_t disk_size, bdev_size;
-
-	spin_lock(&bdev->bd_size_lock);
-	disk_size = (loff_t)get_capacity(disk) << 9;
-	bdev_size = i_size_read(bdev->bd_inode);
-	if (disk_size != bdev_size) {
-		if (verbose) {
-			printk(KERN_INFO
-			       "%s: detected capacity change from %lld to %lld\n",
-			       disk->disk_name, bdev_size, disk_size);
-		}
-		i_size_write(bdev->bd_inode, disk_size);
-	}
-	spin_unlock(&bdev->bd_size_lock);
-}
-
-/**
- * revalidate_disk_size - checks for disk size change and adjusts bdev size.
- * @disk: struct gendisk to check
- * @verbose: if %true log a message about a size change if there is any
- *
- * This routine checks to see if the bdev size does not match the disk size
- * and adjusts it if it differs. When shrinking the bdev size, its all caches
- * are freed.
- */
-void revalidate_disk_size(struct gendisk *disk, bool verbose)
-{
-	struct block_device *bdev;
-
-	/*
-	 * Hidden disks don't have associated bdev so there's no point in
-	 * revalidating them.
-	 */
-	if (disk->flags & GENHD_FL_HIDDEN)
-		return;
-
-	bdev = bdget_disk(disk, 0);
-	if (bdev) {
-		check_disk_size_change(disk, bdev, verbose);
-		bdput(bdev);
-	}
-}
-
-void bd_set_nr_sectors(struct block_device *bdev, sector_t sectors)
-{
-	spin_lock(&bdev->bd_size_lock);
-	i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT);
-	spin_unlock(&bdev->bd_size_lock);
-}
-EXPORT_SYMBOL(bd_set_nr_sectors);
-
 static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);
 
 int bdev_disk_changed(struct block_device *bdev, bool invalidate)
@@ -1300,8 +1236,6 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 			disk->fops->revalidate_disk(disk);
 	}
 
-	check_disk_size_change(disk, bdev, !invalidate);
-
 	if (get_capacity(disk)) {
 		ret = blk_add_partitions(disk, bdev);
 		if (ret == -EAGAIN)
@@ -1344,10 +1278,8 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode)
 			if (disk->fops->open)
 				ret = disk->fops->open(bdev, mode);
 
-			if (!ret) {
-				bd_set_nr_sectors(bdev, get_capacity(disk));
+			if (!ret)
 				set_init_blocksize(bdev);
-			}
 
 			/*
 			 * If the device is invalidated, rescan partition
@@ -1375,12 +1307,11 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode)
 			mutex_unlock(&whole->bd_mutex);
 
 			bdev->bd_part = disk_get_part(disk, bdev->bd_partno);
-			if (!bdev->bd_part || !bdev->bd_part->nr_sects) {
+			if (!bdev_nr_sectors(bdev)) {
 				__blkdev_put(whole, mode, 1);
 				ret = -ENXIO;
 				goto out_clear;
 			}
-			bd_set_nr_sectors(bdev, bdev->bd_part->nr_sects);
 			set_init_blocksize(bdev);
 		}
 
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 00eff2f5180790..d4e7fab352bacb 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -3151,7 +3151,7 @@ static int f2fs_report_zone_cb(struct blk_zone *zone, unsigned int idx,
 static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
 {
 	struct block_device *bdev = FDEV(devi).bdev;
-	sector_t nr_sectors = bdev->bd_part->nr_sects;
+	sector_t nr_sectors = bdev_nr_sectors(bdev);
 	struct f2fs_report_zones_args rep_zone_arg;
 	int ret;
 
diff --git a/fs/pstore/blk.c b/fs/pstore/blk.c
index fcd5563dde063c..777a26f7bbe2aa 100644
--- a/fs/pstore/blk.c
+++ b/fs/pstore/blk.c
@@ -245,7 +245,7 @@ static struct block_device *psblk_get_bdev(void *holder,
 			return bdev;
 	}
 
-	nr_sects = part_nr_sects_read(bdev->bd_part);
+	nr_sects = bdev_nr_sectors(bdev);
 	if (!nr_sects) {
 		pr_err("not enough space for '%s'\n", blkdev);
 		blkdev_put(bdev, mode);
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index dcf86a3d4dedc4..0dbd254bca51aa 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -52,15 +52,6 @@ struct partition_meta_info {
 
 struct hd_struct {
 	sector_t start_sect;
-	/*
-	 * nr_sects is protected by sequence counter. One might extend a
-	 * partition while IO is happening to it and update of nr_sects
-	 * can be non-atomic on 32bit machines with 64bit sector_t.
-	 */
-	sector_t nr_sects;
-#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
-	seqcount_t nr_sects_seq;
-#endif
 	unsigned long stamp;
 	struct disk_stats __percpu *dkstats;
 	struct percpu_ref ref;
@@ -255,13 +246,6 @@ static inline void disk_put_part(struct hd_struct *part)
 		put_device(part_to_dev(part));
 }
 
-static inline void hd_sects_seq_init(struct hd_struct *p)
-{
-#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
-	seqcount_init(&p->nr_sects_seq);
-#endif
-}
-
 /*
  * Smarter partition iterator without context limits.
  */
@@ -319,13 +303,15 @@ static inline sector_t get_start_sect(struct block_device *bdev)
 {
 	return bdev->bd_part->start_sect;
 }
-static inline sector_t get_capacity(struct gendisk *disk)
+
+static inline sector_t bdev_nr_sectors(struct block_device *bdev)
 {
-	return disk->part0.nr_sects;
+	return i_size_read(bdev->bd_inode) >> 9;
 }
-static inline void set_capacity(struct gendisk *disk, sector_t size)
+
+static inline sector_t get_capacity(struct gendisk *disk)
 {
-	disk->part0.nr_sects = size;
+	return bdev_nr_sectors(disk->part0.bdev);
 }
 
 int bdev_disk_changed(struct block_device *bdev, bool invalidate);
@@ -359,10 +345,9 @@ int __register_blkdev(unsigned int major, const char *name,
 	__register_blkdev(major, name, NULL)
 void unregister_blkdev(unsigned int major, const char *name);
 
-void revalidate_disk_size(struct gendisk *disk, bool verbose);
 bool bdev_check_media_change(struct block_device *bdev);
 int __invalidate_device(struct block_device *bdev, bool kill_dirty);
-void bd_set_nr_sectors(struct block_device *bdev, sector_t sectors);
+void set_capacity(struct gendisk *disk, sector_t size);
 
 /* for drivers/char/raw.c: */
 int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long);
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index f1022945e3460b..7076d588a50d69 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -465,7 +465,7 @@ static void blk_trace_setup_lba(struct blk_trace *bt,
 
 	if (part) {
 		bt->start_lba = part->start_sect;
-		bt->end_lba = part->start_sect + part->nr_sects;
+		bt->end_lba = part->start_sect + bdev_nr_sectors(bdev);
 	} else {
 		bt->start_lba = 0;
 		bt->end_lba = -1ULL;
-- 
2.29.2

--
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https://www.redhat.com/mailman/listinfo/dm-devel


^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 31/45] block: move disk stat accounting to struct block_device
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (29 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 30/45] block: remove the nr_sects field in struct hd_struct Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 13:27 ` [dm-devel] [PATCH 32/45] block: move the start_sect field " Christoph Hellwig
                   ` (13 subsequent siblings)
  44 siblings, 0 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Move the dkstats and stamp field to struct block_device in preparation
of killing struct hd_struct.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-cgroup.c        |  2 +-
 block/blk-core.c          |  4 ++--
 block/blk.h               |  1 -
 block/genhd.c             | 14 ++++----------
 block/partitions/core.c   |  9 +--------
 fs/block_dev.c            | 10 ++++++++++
 include/linux/blk_types.h |  2 ++
 include/linux/genhd.h     |  2 --
 include/linux/part_stat.h | 38 +++++++++++++++++++-------------------
 9 files changed, 39 insertions(+), 43 deletions(-)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 23437b96ea41e6..a598f86e014137 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -830,7 +830,7 @@ static void blkcg_fill_root_iostats(void)
 		for_each_possible_cpu(cpu) {
 			struct disk_stats *cpu_dkstats;
 
-			cpu_dkstats = per_cpu_ptr(part->dkstats, cpu);
+			cpu_dkstats = per_cpu_ptr(part->bdev->bd_stats, cpu);
 			tmp.ios[BLKG_IOSTAT_READ] +=
 				cpu_dkstats->ios[STAT_READ];
 			tmp.ios[BLKG_IOSTAT_WRITE] +=
diff --git a/block/blk-core.c b/block/blk-core.c
index 988f45094a387b..d2c9cb24e087f3 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1264,9 +1264,9 @@ static void update_io_ticks(struct hd_struct *part, unsigned long now, bool end)
 {
 	unsigned long stamp;
 again:
-	stamp = READ_ONCE(part->stamp);
+	stamp = READ_ONCE(part->bdev->bd_stamp);
 	if (unlikely(stamp != now)) {
-		if (likely(cmpxchg(&part->stamp, stamp, now) == stamp))
+		if (likely(cmpxchg(&part->bdev->bd_stamp, stamp, now) == stamp))
 			__part_stat_add(part, io_ticks, end ? now - stamp : 1);
 	}
 	if (part->partno) {
diff --git a/block/blk.h b/block/blk.h
index 09cee7024fb43e..3f801f6e86f8a1 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -381,7 +381,6 @@ static inline void hd_struct_put(struct hd_struct *part)
 
 static inline void hd_free_part(struct hd_struct *part)
 {
-	free_percpu(part->dkstats);
 	kfree(part->info);
 	bdput(part->bdev);
 	percpu_ref_exit(&part->ref);
diff --git a/block/genhd.c b/block/genhd.c
index 8ace0628ac20b7..0c0458367da7e4 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -102,7 +102,7 @@ static void part_stat_read_all(struct hd_struct *part, struct disk_stats *stat)
 
 	memset(stat, 0, sizeof(struct disk_stats));
 	for_each_possible_cpu(cpu) {
-		struct disk_stats *ptr = per_cpu_ptr(part->dkstats, cpu);
+		struct disk_stats *ptr = per_cpu_ptr(part->bdev->bd_stats, cpu);
 		int group;
 
 		for (group = 0; group < NR_STAT_GROUPS; group++) {
@@ -875,7 +875,7 @@ void del_gendisk(struct gendisk *disk)
 	kobject_put(disk->slave_dir);
 
 	part_stat_set_all(&disk->part0, 0);
-	disk->part0.stamp = 0;
+	disk->part0.bdev->bd_stamp = 0;
 	if (!sysfs_deprecated)
 		sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
 	pm_runtime_set_memalloc_noio(disk_to_dev(disk), false);
@@ -1612,19 +1612,15 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
 	if (!disk->part0.bdev)
 		goto out_free_disk;
 
-	disk->part0.dkstats = alloc_percpu(struct disk_stats);
-	if (!disk->part0.dkstats)
-		goto out_bdput;
-
 	disk->node_id = node_id;
 	if (disk_expand_part_tbl(disk, 0))
-		goto out_free_bdstats;
+		goto out_bdput;
 
 	ptbl = rcu_dereference_protected(disk->part_tbl, 1);
 	rcu_assign_pointer(ptbl->part[0], &disk->part0);
 
 	if (hd_ref_init(&disk->part0))
-		goto out_free_bdstats;
+		goto out_bdput;
 
 	disk->minors = minors;
 	rand_initialize_disk(disk);
@@ -1633,8 +1629,6 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
 	device_initialize(disk_to_dev(disk));
 	return disk;
 
-out_free_bdstats:
-	free_percpu(disk->part0.dkstats);
 out_bdput:
 	bdput(disk->part0.bdev);
 out_free_disk:
diff --git a/block/partitions/core.c b/block/partitions/core.c
index 92ffa55bdfddfd..c3a4870bfb123d 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -409,14 +409,9 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 	if (!p)
 		return ERR_PTR(-EBUSY);
 
-	err = -ENOMEM;
-	p->dkstats = alloc_percpu(struct disk_stats);
-	if (!p->dkstats)
-		goto out_free;
-
 	bdev = bdev_alloc(disk, partno);
 	if (!bdev)
-		goto out_free_stats;
+		goto out_free;
 	p->bdev = bdev;
 
 	pdev = part_to_dev(p);
@@ -490,8 +485,6 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 	kfree(p->info);
 out_bdput:
 	bdput(bdev);
-out_free_stats:
-	free_percpu(p->dkstats);
 out_free:
 	kfree(p);
 	return ERR_PTR(err);
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 02536d9fa29945..0427e6fa59556f 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -32,6 +32,7 @@
 #include <linux/cleancache.h>
 #include <linux/task_io_accounting_ops.h>
 #include <linux/falloc.h>
+#include <linux/part_stat.h>
 #include <linux/uaccess.h>
 #include <linux/suspend.h>
 #include "internal.h"
@@ -781,6 +782,10 @@ static struct inode *bdev_alloc_inode(struct super_block *sb)
 
 static void bdev_free_inode(struct inode *inode)
 {
+	struct block_device *bdev = I_BDEV(inode);
+
+	free_percpu(bdev->bd_stats);
+
 	kmem_cache_free(bdev_cachep, BDEV_I(inode));
 }
 
@@ -874,6 +879,11 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
 #ifdef CONFIG_SYSFS
 	INIT_LIST_HEAD(&bdev->bd_holder_disks);
 #endif
+	bdev->bd_stats = alloc_percpu(struct disk_stats);
+	if (!bdev->bd_stats) {
+		iput(inode);
+		return NULL;
+	}
 	return bdev;
 }
 
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 2e0a9bd9688d28..520011b95276fb 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -20,6 +20,8 @@ typedef void (bio_end_io_t) (struct bio *);
 struct bio_crypt_ctx;
 
 struct block_device {
+	struct disk_stats __percpu *bd_stats;
+	unsigned long		bd_stamp;
 	dev_t			bd_dev;
 	int			bd_openers;
 	struct inode *		bd_inode;	/* will die */
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 0dbd254bca51aa..dcc40c8217d095 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -52,8 +52,6 @@ struct partition_meta_info {
 
 struct hd_struct {
 	sector_t start_sect;
-	unsigned long stamp;
-	struct disk_stats __percpu *dkstats;
 	struct percpu_ref ref;
 
 	struct block_device *bdev;
diff --git a/include/linux/part_stat.h b/include/linux/part_stat.h
index 24125778ef3ec7..87ad60106e1db0 100644
--- a/include/linux/part_stat.h
+++ b/include/linux/part_stat.h
@@ -25,17 +25,17 @@ struct disk_stats {
 #define part_stat_unlock()	preempt_enable()
 
 #define part_stat_get_cpu(part, field, cpu)				\
-	(per_cpu_ptr((part)->dkstats, (cpu))->field)
+	(per_cpu_ptr((part)->bdev->bd_stats, (cpu))->field)
 
 #define part_stat_get(part, field)					\
 	part_stat_get_cpu(part, field, smp_processor_id())
 
 #define part_stat_read(part, field)					\
 ({									\
-	typeof((part)->dkstats->field) res = 0;				\
+	typeof((part)->bdev->bd_stats->field) res = 0;			\
 	unsigned int _cpu;						\
 	for_each_possible_cpu(_cpu)					\
-		res += per_cpu_ptr((part)->dkstats, _cpu)->field;	\
+		res += per_cpu_ptr((part)->bdev->bd_stats, _cpu)->field; \
 	res;								\
 })
 
@@ -44,7 +44,7 @@ static inline void part_stat_set_all(struct hd_struct *part, int value)
 	int i;
 
 	for_each_possible_cpu(i)
-		memset(per_cpu_ptr(part->dkstats, i), value,
+		memset(per_cpu_ptr(part->bdev->bd_stats, i), value,
 				sizeof(struct disk_stats));
 }
 
@@ -54,7 +54,7 @@ static inline void part_stat_set_all(struct hd_struct *part, int value)
 	 part_stat_read(part, field[STAT_DISCARD]))
 
 #define __part_stat_add(part, field, addnd)				\
-	__this_cpu_add((part)->dkstats->field, addnd)
+	__this_cpu_add((part)->bdev->bd_stats->field, addnd)
 
 #define part_stat_add(part, field, addnd)	do {			\
 	__part_stat_add((part), field, addnd);				\
@@ -63,20 +63,20 @@ static inline void part_stat_set_all(struct hd_struct *part, int value)
 				field, addnd);				\
 } while (0)
 
-#define part_stat_dec(gendiskp, field)					\
-	part_stat_add(gendiskp, field, -1)
-#define part_stat_inc(gendiskp, field)					\
-	part_stat_add(gendiskp, field, 1)
-#define part_stat_sub(gendiskp, field, subnd)				\
-	part_stat_add(gendiskp, field, -subnd)
+#define part_stat_dec(part, field)					\
+	part_stat_add(part, field, -1)
+#define part_stat_inc(part, field)					\
+	part_stat_add(part, field, 1)
+#define part_stat_sub(part, field, subnd)				\
+	part_stat_add(part, field, -subnd)
 
-#define part_stat_local_dec(gendiskp, field)				\
-	local_dec(&(part_stat_get(gendiskp, field)))
-#define part_stat_local_inc(gendiskp, field)				\
-	local_inc(&(part_stat_get(gendiskp, field)))
-#define part_stat_local_read(gendiskp, field)				\
-	local_read(&(part_stat_get(gendiskp, field)))
-#define part_stat_local_read_cpu(gendiskp, field, cpu)			\
-	local_read(&(part_stat_get_cpu(gendiskp, field, cpu)))
+#define part_stat_local_dec(part, field)				\
+	local_dec(&(part_stat_get(part, field)))
+#define part_stat_local_inc(part, field)				\
+	local_inc(&(part_stat_get(part, field)))
+#define part_stat_local_read(part, field)				\
+	local_read(&(part_stat_get(part, field)))
+#define part_stat_local_read_cpu(part, field, cpu)			\
+	local_read(&(part_stat_get_cpu(part, field, cpu)))
 
 #endif /* _LINUX_PART_STAT_H */
-- 
2.29.2

--
dm-devel mailing list
dm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel


^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 32/45] block: move the start_sect field to struct block_device
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (30 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 31/45] block: move disk stat accounting to struct block_device Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 13:27 ` [dm-devel] [PATCH 33/45] block: move the partition_meta_info " Christoph Hellwig
                   ` (12 subsequent siblings)
  44 siblings, 0 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Move the start_sect field to struct block_device in preparation
of killing struct hd_struct.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-core.c          |  5 +++--
 block/blk-lib.c           |  2 +-
 block/genhd.c             |  4 ++--
 block/partitions/core.c   | 17 +++++++++--------
 include/linux/blk_types.h |  1 +
 include/linux/blkdev.h    |  4 ++--
 include/linux/genhd.h     |  3 +--
 kernel/trace/blktrace.c   | 11 +++--------
 8 files changed, 22 insertions(+), 25 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index d2c9cb24e087f3..9a3793d5ce38d4 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -757,9 +757,10 @@ static inline int blk_partition_remap(struct bio *bio)
 	if (bio_sectors(bio)) {
 		if (bio_check_eod(bio, bdev_nr_sectors(p->bdev)))
 			goto out;
-		bio->bi_iter.bi_sector += p->start_sect;
+		bio->bi_iter.bi_sector += p->bdev->bd_start_sect;
 		trace_block_bio_remap(bio->bi_disk->queue, bio, part_devt(p),
-				      bio->bi_iter.bi_sector - p->start_sect);
+				      bio->bi_iter.bi_sector -
+				      p->bdev->bd_start_sect);
 	}
 	bio->bi_partno = 0;
 	ret = 0;
diff --git a/block/blk-lib.c b/block/blk-lib.c
index e90614fd8d6a42..752f9c7220622a 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -65,7 +65,7 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 
 	/* In case the discard request is in a partition */
 	if (bdev_is_partition(bdev))
-		part_offset = bdev->bd_part->start_sect;
+		part_offset = bdev->bd_start_sect;
 
 	while (nr_sects) {
 		sector_t granularity_aligned_lba, req_sects;
diff --git a/block/genhd.c b/block/genhd.c
index 0c0458367da7e4..8212a2dd10ec4e 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -295,8 +295,8 @@ EXPORT_SYMBOL_GPL(disk_part_iter_exit);
 
 static inline int sector_in_part(struct hd_struct *part, sector_t sector)
 {
-	return part->start_sect <= sector &&
-		sector < part->start_sect + bdev_nr_sectors(part->bdev);
+	return part->bdev->bd_start_sect <= sector &&
+		sector < part->bdev->bd_start_sect + bdev_nr_sectors(part->bdev);
 }
 
 /**
diff --git a/block/partitions/core.c b/block/partitions/core.c
index c3a4870bfb123d..aa4b836374b037 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -192,7 +192,7 @@ static ssize_t part_start_show(struct device *dev,
 {
 	struct hd_struct *p = dev_to_part(dev);
 
-	return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect);
+	return sprintf(buf, "%llu\n",(unsigned long long)p->bdev->bd_start_sect);
 }
 
 static ssize_t part_ro_show(struct device *dev,
@@ -209,7 +209,7 @@ static ssize_t part_alignment_offset_show(struct device *dev,
 
 	return sprintf(buf, "%u\n",
 		queue_limit_alignment_offset(&part_to_disk(p)->queue->limits,
-				p->start_sect));
+				p->bdev->bd_start_sect));
 }
 
 static ssize_t part_discard_alignment_show(struct device *dev,
@@ -219,7 +219,7 @@ static ssize_t part_discard_alignment_show(struct device *dev,
 
 	return sprintf(buf, "%u\n",
 		queue_limit_discard_alignment(&part_to_disk(p)->queue->limits,
-				p->start_sect));
+				p->bdev->bd_start_sect));
 }
 
 static DEVICE_ATTR(partition, 0444, part_partition_show, NULL);
@@ -301,7 +301,7 @@ static void hd_struct_free_work(struct work_struct *work)
 	 */
 	put_device(disk_to_dev(disk));
 
-	part->start_sect = 0;
+	part->bdev->bd_start_sect = 0;
 	bdev_set_nr_sectors(part->bdev, 0);
 	part_stat_set_all(part, 0);
 	put_device(part_to_dev(part));
@@ -416,7 +416,7 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 
 	pdev = part_to_dev(p);
 
-	p->start_sect = start;
+	bdev->bd_start_sect = start;
 	bdev_set_nr_sectors(bdev, len);
 	p->partno = partno;
 	p->policy = get_disk_ro(disk);
@@ -508,8 +508,9 @@ static bool partition_overlaps(struct gendisk *disk, sector_t start,
 	disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
 	while ((part = disk_part_iter_next(&piter))) {
 		if (part->partno == skip_partno ||
-		    start >= part->start_sect + bdev_nr_sectors(part->bdev) ||
-		    start + length <= part->start_sect)
+		    start >= part->bdev->bd_start_sect +
+			bdev_nr_sectors(part->bdev) ||
+		    start + length <= part->bdev->bd_start_sect)
 			continue;
 		overlap = true;
 		break;
@@ -592,7 +593,7 @@ int bdev_resize_partition(struct block_device *bdev, int partno,
 	mutex_lock_nested(&bdev->bd_mutex, 1);
 
 	ret = -EINVAL;
-	if (start != part->start_sect)
+	if (start != part->bdev->bd_start_sect)
 		goto out_unlock;
 
 	ret = -EBUSY;
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 520011b95276fb..a690008f60cd92 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -20,6 +20,7 @@ typedef void (bio_end_io_t) (struct bio *);
 struct bio_crypt_ctx;
 
 struct block_device {
+	sector_t		bd_start_sect;
 	struct disk_stats __percpu *bd_stats;
 	unsigned long		bd_stamp;
 	dev_t			bd_dev;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index db1b11d6d07568..8fc0b266610f7f 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1488,7 +1488,7 @@ static inline int bdev_alignment_offset(struct block_device *bdev)
 		return -1;
 	if (bdev_is_partition(bdev))
 		return queue_limit_alignment_offset(&q->limits,
-				bdev->bd_part->start_sect);
+				bdev->bd_start_sect);
 	return q->limits.alignment_offset;
 }
 
@@ -1529,7 +1529,7 @@ static inline int bdev_discard_alignment(struct block_device *bdev)
 
 	if (bdev_is_partition(bdev))
 		return queue_limit_discard_alignment(&q->limits,
-				bdev->bd_part->start_sect);
+				bdev->bd_start_sect);
 	return q->limits.discard_alignment;
 }
 
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index dcc40c8217d095..a9d64da474233f 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -51,7 +51,6 @@ struct partition_meta_info {
 };
 
 struct hd_struct {
-	sector_t start_sect;
 	struct percpu_ref ref;
 
 	struct block_device *bdev;
@@ -299,7 +298,7 @@ extern void rand_initialize_disk(struct gendisk *disk);
 
 static inline sector_t get_start_sect(struct block_device *bdev)
 {
-	return bdev->bd_part->start_sect;
+	return bdev->bd_start_sect;
 }
 
 static inline sector_t bdev_nr_sectors(struct block_device *bdev)
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 7076d588a50d69..8a723a91ec5a06 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -458,14 +458,9 @@ static struct rchan_callbacks blk_relay_callbacks = {
 static void blk_trace_setup_lba(struct blk_trace *bt,
 				struct block_device *bdev)
 {
-	struct hd_struct *part = NULL;
-
-	if (bdev)
-		part = bdev->bd_part;
-
-	if (part) {
-		bt->start_lba = part->start_sect;
-		bt->end_lba = part->start_sect + bdev_nr_sectors(bdev);
+	if (bdev) {
+		bt->start_lba = bdev->bd_start_sect;
+		bt->end_lba = bdev->bd_start_sect + bdev_nr_sectors(bdev);
 	} else {
 		bt->start_lba = 0;
 		bt->end_lba = -1ULL;
-- 
2.29.2

--
dm-devel mailing list
dm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel


^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 33/45] block: move the partition_meta_info to struct block_device
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (31 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 32/45] block: move the start_sect field " Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 13:27 ` [dm-devel] [PATCH 34/45] block: move holder_dir " Christoph Hellwig
                   ` (11 subsequent siblings)
  44 siblings, 0 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Move the partition_meta_info to struct block_device in preparation for
killing struct hd_struct.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk.h               |  1 -
 block/genhd.c             |  3 ++-
 block/partitions/core.c   | 18 +++++++-----------
 fs/block_dev.c            |  1 +
 include/linux/blk_types.h |  2 ++
 include/linux/genhd.h     |  1 -
 init/do_mounts.c          |  7 ++++---
 7 files changed, 16 insertions(+), 17 deletions(-)

diff --git a/block/blk.h b/block/blk.h
index 3f801f6e86f8a1..0bd4b58bcbaf77 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -381,7 +381,6 @@ static inline void hd_struct_put(struct hd_struct *part)
 
 static inline void hd_free_part(struct hd_struct *part)
 {
-	kfree(part->info);
 	bdput(part->bdev);
 	percpu_ref_exit(&part->ref);
 }
diff --git a/block/genhd.c b/block/genhd.c
index 8212a2dd10ec4e..20c7bf6d091e94 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -994,7 +994,8 @@ void __init printk_all_partitions(void)
 			       bdevt_str(part_devt(part), devt_buf),
 			       bdev_nr_sectors(part->bdev) >> 1,
 			       disk_name(disk, part->partno, name_buf),
-			       part->info ? part->info->uuid : "");
+			       part->bdev->bd_meta_info ?
+					part->bdev->bd_meta_info->uuid : "");
 			if (is_part0) {
 				if (dev->parent && dev->parent->driver)
 					printk(" driver: %s\n",
diff --git a/block/partitions/core.c b/block/partitions/core.c
index aa4b836374b037..e24673b4cba61f 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -275,8 +275,9 @@ static int part_uevent(struct device *dev, struct kobj_uevent_env *env)
 	struct hd_struct *part = dev_to_part(dev);
 
 	add_uevent_var(env, "PARTN=%u", part->partno);
-	if (part->info && part->info->volname[0])
-		add_uevent_var(env, "PARTNAME=%s", part->info->volname);
+	if (part->bdev->bd_meta_info && part->bdev->bd_meta_info->volname[0])
+		add_uevent_var(env, "PARTNAME=%s",
+			       part->bdev->bd_meta_info->volname);
 	return 0;
 }
 
@@ -422,13 +423,10 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 	p->policy = get_disk_ro(disk);
 
 	if (info) {
-		struct partition_meta_info *pinfo;
-
-		pinfo = kzalloc_node(sizeof(*pinfo), GFP_KERNEL, disk->node_id);
-		if (!pinfo)
+		err = -ENOMEM;
+		bdev->bd_meta_info = kmemdup(info, sizeof(*info), GFP_KERNEL);
+		if (!bdev->bd_meta_info)
 			goto out_bdput;
-		memcpy(pinfo, info, sizeof(*info));
-		p->info = pinfo;
 	}
 
 	dname = dev_name(ddev);
@@ -444,7 +442,7 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 
 	err = blk_alloc_devt(p, &devt);
 	if (err)
-		goto out_free_info;
+		goto out_bdput;
 	pdev->devt = devt;
 
 	/* delay uevent until 'holders' subdir is created */
@@ -481,8 +479,6 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 		kobject_uevent(&pdev->kobj, KOBJ_ADD);
 	return p;
 
-out_free_info:
-	kfree(p->info);
 out_bdput:
 	bdput(bdev);
 out_free:
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 0427e6fa59556f..2393395201aa6c 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -785,6 +785,7 @@ static void bdev_free_inode(struct inode *inode)
 	struct block_device *bdev = I_BDEV(inode);
 
 	free_percpu(bdev->bd_stats);
+	kfree(bdev->bd_meta_info);
 
 	kmem_cache_free(bdev_cachep, BDEV_I(inode));
 }
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index a690008f60cd92..2f8ede04e5a94c 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -49,6 +49,8 @@ struct block_device {
 	/* Mutex for freeze */
 	struct mutex		bd_fsfreeze_mutex;
 	struct super_block	*bd_fsfreeze_sb;
+
+	struct partition_meta_info *bd_meta_info;
 } __randomize_layout;
 
 #define bdev_whole(_bdev) \
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index a9d64da474233f..1e52f38b719db3 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -57,7 +57,6 @@ struct hd_struct {
 	struct device __dev;
 	struct kobject *holder_dir;
 	int policy, partno;
-	struct partition_meta_info *info;
 #ifdef CONFIG_FAIL_MAKE_REQUEST
 	int make_it_fail;
 #endif
diff --git a/init/do_mounts.c b/init/do_mounts.c
index 5879edf083b318..368ccb71850126 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -79,8 +79,8 @@ static int match_dev_by_uuid(struct device *dev, const void *data)
 	const struct uuidcmp *cmp = data;
 	struct hd_struct *part = dev_to_part(dev);
 
-	if (!part->info ||
-	    strncasecmp(cmp->uuid, part->info->uuid, cmp->len))
+	if (!part->bdev->bd_meta_info ||
+	    strncasecmp(cmp->uuid, part->bdev->bd_meta_info->uuid, cmp->len))
 		return 0;
 	return 1;
 }
@@ -169,7 +169,8 @@ static int match_dev_by_label(struct device *dev, const void *data)
 	const char *label = data;
 	struct hd_struct *part = dev_to_part(dev);
 
-	if (!part->info || strcmp(label, part->info->volname))
+	if (!part->bdev->bd_meta_info ||
+	    strcmp(label, part->bdev->bd_meta_info->volname))
 		return 0;
 	return 1;
 }
-- 
2.29.2

--
dm-devel mailing list
dm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel


^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 34/45] block: move holder_dir to struct block_device
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (32 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 33/45] block: move the partition_meta_info " Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 13:27 ` [dm-devel] [PATCH 35/45] block: move make_it_fail " Christoph Hellwig
                   ` (10 subsequent siblings)
  44 siblings, 0 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Move the holder_dir field to struct block_device in preparation for
kill struct hd_struct.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c             |  5 +++--
 block/partitions/core.c   |  8 ++++----
 fs/block_dev.c            | 11 +++++------
 include/linux/blk_types.h |  1 +
 include/linux/genhd.h     |  1 -
 5 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 20c7bf6d091e94..a991f0122e53d8 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -671,7 +671,8 @@ static void register_disk(struct device *parent, struct gendisk *disk,
 	 */
 	pm_runtime_set_memalloc_noio(ddev, true);
 
-	disk->part0.holder_dir = kobject_create_and_add("holders", &ddev->kobj);
+	disk->part0.bdev->bd_holder_dir =
+			kobject_create_and_add("holders", &ddev->kobj);
 	disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
 
 	if (disk->flags & GENHD_FL_HIDDEN) {
@@ -871,7 +872,7 @@ void del_gendisk(struct gendisk *disk)
 
 	blk_unregister_queue(disk);
 
-	kobject_put(disk->part0.holder_dir);
+	kobject_put(disk->part0.bdev->bd_holder_dir);
 	kobject_put(disk->slave_dir);
 
 	part_stat_set_all(&disk->part0, 0);
diff --git a/block/partitions/core.c b/block/partitions/core.c
index e24673b4cba61f..ff60a14ed4dcdd 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -344,7 +344,7 @@ void delete_partition(struct hd_struct *part)
 	 */
 	get_device(disk_to_dev(disk));
 	rcu_assign_pointer(ptbl->part[part->partno], NULL);
-	kobject_put(part->holder_dir);
+	kobject_put(part->bdev->bd_holder_dir);
 	device_del(part_to_dev(part));
 
 	/*
@@ -452,8 +452,8 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 		goto out_put;
 
 	err = -ENOMEM;
-	p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
-	if (!p->holder_dir)
+	bdev->bd_holder_dir = kobject_create_and_add("holders", &pdev->kobj);
+	if (!bdev->bd_holder_dir)
 		goto out_del;
 
 	dev_set_uevent_suppress(pdev, 0);
@@ -487,7 +487,7 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 out_remove_file:
 	device_remove_file(pdev, &dev_attr_whole_disk);
 out_del:
-	kobject_put(p->holder_dir);
+	kobject_put(bdev->bd_holder_dir);
 	device_del(pdev);
 out_put:
 	put_device(pdev);
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 2393395201aa6c..0b8d6009486643 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1137,7 +1137,7 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
 	WARN_ON_ONCE(!bdev->bd_holder);
 
 	/* FIXME: remove the following once add_disk() handles errors */
-	if (WARN_ON(!disk->slave_dir || !bdev->bd_part->holder_dir))
+	if (WARN_ON(!disk->slave_dir || !bdev->bd_holder_dir))
 		goto out_unlock;
 
 	holder = bd_find_holder_disk(bdev, disk);
@@ -1160,14 +1160,14 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
 	if (ret)
 		goto out_free;
 
-	ret = add_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj);
+	ret = add_symlink(bdev->bd_holder_dir, &disk_to_dev(disk)->kobj);
 	if (ret)
 		goto out_del;
 	/*
 	 * bdev could be deleted beneath us which would implicitly destroy
 	 * the holder directory.  Hold on to it.
 	 */
-	kobject_get(bdev->bd_part->holder_dir);
+	kobject_get(bdev->bd_holder_dir);
 
 	list_add(&holder->list, &bdev->bd_holder_disks);
 	goto out_unlock;
@@ -1202,9 +1202,8 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
 
 	if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) {
 		del_symlink(disk->slave_dir, bdev_kobj(bdev));
-		del_symlink(bdev->bd_part->holder_dir,
-			    &disk_to_dev(disk)->kobj);
-		kobject_put(bdev->bd_part->holder_dir);
+		del_symlink(bdev->bd_holder_dir, &disk_to_dev(disk)->kobj);
+		kobject_put(bdev->bd_holder_dir);
 		list_del_init(&holder->list);
 		kfree(holder);
 	}
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 2f8ede04e5a94c..c0591e52d7d7ce 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -35,6 +35,7 @@ struct block_device {
 #ifdef CONFIG_SYSFS
 	struct list_head	bd_holder_disks;
 #endif
+	struct kobject		*bd_holder_dir;
 	u8			bd_partno;
 	struct hd_struct *	bd_part;
 	/* number of times partitions within this device have been opened. */
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 1e52f38b719db3..c2a8cf12c5cab5 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -55,7 +55,6 @@ struct hd_struct {
 
 	struct block_device *bdev;
 	struct device __dev;
-	struct kobject *holder_dir;
 	int policy, partno;
 #ifdef CONFIG_FAIL_MAKE_REQUEST
 	int make_it_fail;
-- 
2.29.2

--
dm-devel mailing list
dm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel


^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 35/45] block: move make_it_fail to struct block_device
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (33 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 34/45] block: move holder_dir " Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 13:27 ` [dm-devel] [PATCH 36/45] block: move the policy field " Christoph Hellwig
                   ` (9 subsequent siblings)
  44 siblings, 0 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Move the make_it_fail flag to struct block_device an turn it into a bool
in preparation of killing struct hd_struct.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-core.c          | 3 ++-
 block/genhd.c             | 4 ++--
 include/linux/blk_types.h | 3 +++
 include/linux/genhd.h     | 3 ---
 4 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 9a3793d5ce38d4..9121390be97a76 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -668,7 +668,8 @@ __setup("fail_make_request=", setup_fail_make_request);
 
 static bool should_fail_request(struct hd_struct *part, unsigned int bytes)
 {
-	return part->make_it_fail && should_fail(&fail_make_request, bytes);
+	return part->bdev->bd_make_it_fail &&
+		should_fail(&fail_make_request, bytes);
 }
 
 static int __init fail_make_request_debugfs(void)
diff --git a/block/genhd.c b/block/genhd.c
index a991f0122e53d8..8c734a4e8ff31c 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1276,7 +1276,7 @@ ssize_t part_fail_show(struct device *dev,
 {
 	struct hd_struct *p = dev_to_part(dev);
 
-	return sprintf(buf, "%d\n", p->make_it_fail);
+	return sprintf(buf, "%d\n", p->bdev->bd_make_it_fail);
 }
 
 ssize_t part_fail_store(struct device *dev,
@@ -1287,7 +1287,7 @@ ssize_t part_fail_store(struct device *dev,
 	int i;
 
 	if (count > 0 && sscanf(buf, "%d", &i) > 0)
-		p->make_it_fail = (i == 0) ? 0 : 1;
+		p->pdev->bd_make_it_fail = (i == 0) ? 0 : 1;
 
 	return count;
 }
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index c0591e52d7d7ce..b237f1e4081405 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -52,6 +52,9 @@ struct block_device {
 	struct super_block	*bd_fsfreeze_sb;
 
 	struct partition_meta_info *bd_meta_info;
+#ifdef CONFIG_FAIL_MAKE_REQUEST
+	bool			bd_make_it_fail;
+#endif
 } __randomize_layout;
 
 #define bdev_whole(_bdev) \
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index c2a8cf12c5cab5..5d46ea7be7e4f0 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -56,9 +56,6 @@ struct hd_struct {
 	struct block_device *bdev;
 	struct device __dev;
 	int policy, partno;
-#ifdef CONFIG_FAIL_MAKE_REQUEST
-	int make_it_fail;
-#endif
 	struct rcu_work rcu_work;
 };
 
-- 
2.29.2

--
dm-devel mailing list
dm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel


^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 36/45] block: move the policy field to struct block_device
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (34 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 35/45] block: move make_it_fail " Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 13:27 ` [dm-devel] [PATCH 37/45] block: allocate struct hd_struct as part of struct bdev_inode Christoph Hellwig
                   ` (8 subsequent siblings)
  44 siblings, 0 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Move the policy field to struct block_device and rename it to the
more descriptive bd_read_only.  Also turn the field into a bool as it
is used as such.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-core.c          | 2 +-
 block/genhd.c             | 8 ++++----
 block/ioctl.c             | 2 +-
 block/partitions/core.c   | 4 ++--
 include/linux/blk_types.h | 1 +
 include/linux/genhd.h     | 4 ++--
 6 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 9121390be97a76..d64ffcb6f9ae5d 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -696,7 +696,7 @@ static inline bool bio_check_ro(struct bio *bio, struct hd_struct *part)
 {
 	const int op = bio_op(bio);
 
-	if (part->policy && op_is_write(op)) {
+	if (part->bdev->bd_read_only && op_is_write(op)) {
 		char b[BDEVNAME_SIZE];
 
 		if (op_is_flush(bio->bi_opf) && !bio_sectors(bio))
diff --git a/block/genhd.c b/block/genhd.c
index 8c734a4e8ff31c..8aed77cc8ad169 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1671,14 +1671,14 @@ void set_disk_ro(struct gendisk *disk, int flag)
 	struct disk_part_iter piter;
 	struct hd_struct *part;
 
-	if (disk->part0.policy != flag) {
+	if (disk->part0.bdev->bd_read_only != flag) {
 		set_disk_ro_uevent(disk, flag);
-		disk->part0.policy = flag;
+		disk->part0.bdev->bd_read_only = flag;
 	}
 
 	disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
 	while ((part = disk_part_iter_next(&piter)))
-		part->policy = flag;
+		part->bdev->bd_read_only = flag;
 	disk_part_iter_exit(&piter);
 }
 
@@ -1688,7 +1688,7 @@ int bdev_read_only(struct block_device *bdev)
 {
 	if (!bdev)
 		return 0;
-	return bdev->bd_part->policy;
+	return bdev->bd_read_only;
 }
 
 EXPORT_SYMBOL(bdev_read_only);
diff --git a/block/ioctl.c b/block/ioctl.c
index a6d8171221c7dc..d61d652078f41c 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -345,7 +345,7 @@ static int blkdev_roset(struct block_device *bdev, fmode_t mode,
 		if (ret)
 			return ret;
 	}
-	bdev->bd_part->policy = n;
+	bdev->bd_read_only = n;
 	return 0;
 }
 
diff --git a/block/partitions/core.c b/block/partitions/core.c
index ff60a14ed4dcdd..fd00428e437a63 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -199,7 +199,7 @@ static ssize_t part_ro_show(struct device *dev,
 			    struct device_attribute *attr, char *buf)
 {
 	struct hd_struct *p = dev_to_part(dev);
-	return sprintf(buf, "%d\n", p->policy ? 1 : 0);
+	return sprintf(buf, "%d\n", p->bdev->bd_read_only);
 }
 
 static ssize_t part_alignment_offset_show(struct device *dev,
@@ -420,7 +420,7 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 	bdev->bd_start_sect = start;
 	bdev_set_nr_sectors(bdev, len);
 	p->partno = partno;
-	p->policy = get_disk_ro(disk);
+	bdev->bd_read_only = get_disk_ro(disk);
 
 	if (info) {
 		err = -ENOMEM;
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index b237f1e4081405..758cf71c9aa2a6 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -23,6 +23,7 @@ struct block_device {
 	sector_t		bd_start_sect;
 	struct disk_stats __percpu *bd_stats;
 	unsigned long		bd_stamp;
+	bool			bd_read_only;	/* read-only policy */
 	dev_t			bd_dev;
 	int			bd_openers;
 	struct inode *		bd_inode;	/* will die */
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 5d46ea7be7e4f0..08d00b526b0a3b 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -55,7 +55,7 @@ struct hd_struct {
 
 	struct block_device *bdev;
 	struct device __dev;
-	int policy, partno;
+	int partno;
 	struct rcu_work rcu_work;
 };
 
@@ -279,7 +279,7 @@ extern void set_disk_ro(struct gendisk *disk, int flag);
 
 static inline int get_disk_ro(struct gendisk *disk)
 {
-	return disk->part0.policy;
+	return disk->part0.bdev->bd_read_only;
 }
 
 extern void disk_block_events(struct gendisk *disk);
-- 
2.29.2

--
dm-devel mailing list
dm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel


^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 37/45] block: allocate struct hd_struct as part of struct bdev_inode
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (35 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 36/45] block: move the policy field " Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 13:27 ` [dm-devel] [PATCH 38/45] block: switch partition lookup to use struct block_device Christoph Hellwig
                   ` (7 subsequent siblings)
  44 siblings, 0 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Allocate hd_struct together with struct block_device to pre-load
the lifetime rule changes in preparation of merging the two structures.

Note that part0 was previously embedded into struct gendisk, but is
a separate allocation now, and already points to the block_device instead
of the hd_struct.  The lifetime of struct gendisk is still controlled by
the struct device embedded in the part0 hd_struct.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-core.c                   | 16 ++++---
 block/blk-flush.c                  |  2 +-
 block/blk-merge.c                  |  2 -
 block/blk.h                        | 21 ----------
 block/genhd.c                      | 50 +++++++++-------------
 block/partitions/core.c            | 67 +++---------------------------
 drivers/block/drbd/drbd_receiver.c |  2 +-
 drivers/block/drbd/drbd_worker.c   |  3 +-
 drivers/block/zram/zram_drv.c      |  2 +-
 drivers/md/dm.c                    |  4 +-
 drivers/md/md.c                    |  2 +-
 fs/block_dev.c                     | 37 +++++------------
 include/linux/blk_types.h          |  2 +-
 include/linux/genhd.h              | 14 +++----
 include/linux/part_stat.h          |  4 +-
 15 files changed, 60 insertions(+), 168 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index d64ffcb6f9ae5d..9ea70275fc1cfe 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -714,7 +714,8 @@ static inline bool bio_check_ro(struct bio *bio, struct hd_struct *part)
 
 static noinline int should_fail_bio(struct bio *bio)
 {
-	if (should_fail_request(&bio->bi_disk->part0, bio->bi_iter.bi_size))
+	if (should_fail_request(bio->bi_disk->part0->bd_part,
+			bio->bi_iter.bi_size))
 		return -EIO;
 	return 0;
 }
@@ -831,7 +832,7 @@ static noinline_for_stack bool submit_bio_checks(struct bio *bio)
 		if (unlikely(blk_partition_remap(bio)))
 			goto end_io;
 	} else {
-		if (unlikely(bio_check_ro(bio, &bio->bi_disk->part0)))
+		if (unlikely(bio_check_ro(bio, bio->bi_disk->part0->bd_part)))
 			goto end_io;
 		if (unlikely(bio_check_eod(bio, get_capacity(bio->bi_disk))))
 			goto end_io;
@@ -1203,7 +1204,7 @@ blk_status_t blk_insert_cloned_request(struct request_queue *q, struct request *
 		return ret;
 
 	if (rq->rq_disk &&
-	    should_fail_request(&rq->rq_disk->part0, blk_rq_bytes(rq)))
+	    should_fail_request(rq->rq_disk->part0->bd_part, blk_rq_bytes(rq)))
 		return BLK_STS_IOERR;
 
 	if (blk_crypto_insert_cloned_request(rq))
@@ -1272,7 +1273,7 @@ static void update_io_ticks(struct hd_struct *part, unsigned long now, bool end)
 			__part_stat_add(part, io_ticks, end ? now - stamp : 1);
 	}
 	if (part->partno) {
-		part = &part_to_disk(part)->part0;
+		part = part_to_disk(part)->part0->bd_part;
 		goto again;
 	}
 }
@@ -1309,8 +1310,6 @@ void blk_account_io_done(struct request *req, u64 now)
 		part_stat_inc(part, ios[sgrp]);
 		part_stat_add(part, nsecs[sgrp], now - req->start_time_ns);
 		part_stat_unlock();
-
-		hd_struct_put(part);
 	}
 }
 
@@ -1354,7 +1353,7 @@ EXPORT_SYMBOL_GPL(part_start_io_acct);
 unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors,
 				 unsigned int op)
 {
-	return __part_start_io_acct(&disk->part0, sectors, op);
+	return __part_start_io_acct(disk->part0->bd_part, sectors, op);
 }
 EXPORT_SYMBOL(disk_start_io_acct);
 
@@ -1376,14 +1375,13 @@ void part_end_io_acct(struct hd_struct *part, struct bio *bio,
 		      unsigned long start_time)
 {
 	__part_end_io_acct(part, bio_op(bio), start_time);
-	hd_struct_put(part);
 }
 EXPORT_SYMBOL_GPL(part_end_io_acct);
 
 void disk_end_io_acct(struct gendisk *disk, unsigned int op,
 		      unsigned long start_time)
 {
-	__part_end_io_acct(&disk->part0, op, start_time);
+	__part_end_io_acct(disk->part0->bd_part, op, start_time);
 }
 EXPORT_SYMBOL(disk_end_io_acct);
 
diff --git a/block/blk-flush.c b/block/blk-flush.c
index e32958f0b68750..fcd0a60574dff8 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -139,7 +139,7 @@ static void blk_flush_queue_rq(struct request *rq, bool add_front)
 
 static void blk_account_io_flush(struct request *rq)
 {
-	struct hd_struct *part = &rq->rq_disk->part0;
+	struct hd_struct *part = rq->rq_disk->part0->bd_part;
 
 	part_stat_lock();
 	part_stat_inc(part, ios[STAT_FLUSH]);
diff --git a/block/blk-merge.c b/block/blk-merge.c
index bcf5e458060337..cb351ab9b77dbd 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -683,8 +683,6 @@ static void blk_account_io_merge_request(struct request *req)
 		part_stat_lock();
 		part_stat_inc(req->part, merges[op_stat_group(req_op(req))]);
 		part_stat_unlock();
-
-		hd_struct_put(req->part);
 	}
 }
 
diff --git a/block/blk.h b/block/blk.h
index 0bd4b58bcbaf77..32ac41f7557fcc 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -363,27 +363,6 @@ int bdev_del_partition(struct block_device *bdev, int partno);
 int bdev_resize_partition(struct block_device *bdev, int partno,
 		sector_t start, sector_t length);
 int disk_expand_part_tbl(struct gendisk *disk, int target);
-int hd_ref_init(struct hd_struct *part);
-
-/* no need to get/put refcount of part0 */
-static inline int hd_struct_try_get(struct hd_struct *part)
-{
-	if (part->partno)
-		return percpu_ref_tryget_live(&part->ref);
-	return 1;
-}
-
-static inline void hd_struct_put(struct hd_struct *part)
-{
-	if (part->partno)
-		percpu_ref_put(&part->ref);
-}
-
-static inline void hd_free_part(struct hd_struct *part)
-{
-	bdput(part->bdev);
-	percpu_ref_exit(&part->ref);
-}
 
 int bio_add_hw_page(struct request_queue *q, struct bio *bio,
 		struct page *page, unsigned int len, unsigned int offset,
diff --git a/block/genhd.c b/block/genhd.c
index 8aed77cc8ad169..3bbf6d3a69ec63 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -40,7 +40,7 @@ static void disk_release_events(struct gendisk *disk);
 
 void set_capacity(struct gendisk *disk, sector_t sectors)
 {
-	struct block_device *bdev = disk->part0.bdev;
+	struct block_device *bdev = disk->part0;
 
 	spin_lock(&bdev->bd_size_lock);
 	i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT);
@@ -308,9 +308,7 @@ static inline int sector_in_part(struct hd_struct *part, sector_t sector)
  * primarily used for stats accounting.
  *
  * CONTEXT:
- * RCU read locked.  The returned partition pointer is always valid
- * because its refcount is grabbed except for part0, which lifetime
- * is same with the disk.
+ * RCU read locked.
  *
  * RETURNS:
  * Found partition on success, part0 is returned if no partition matches
@@ -326,26 +324,19 @@ struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector)
 	ptbl = rcu_dereference(disk->part_tbl);
 
 	part = rcu_dereference(ptbl->last_lookup);
-	if (part && sector_in_part(part, sector) && hd_struct_try_get(part))
+	if (part && sector_in_part(part, sector))
 		goto out_unlock;
 
 	for (i = 1; i < ptbl->len; i++) {
 		part = rcu_dereference(ptbl->part[i]);
 
 		if (part && sector_in_part(part, sector)) {
-			/*
-			 * only live partition can be cached for lookup,
-			 * so use-after-free on cached & deleting partition
-			 * can be avoided
-			 */
-			if (!hd_struct_try_get(part))
-				break;
 			rcu_assign_pointer(ptbl->last_lookup, part);
 			goto out_unlock;
 		}
 	}
 
-	part = &disk->part0;
+	part = disk->part0->bd_part;
 out_unlock:
 	rcu_read_unlock();
 	return part;
@@ -671,8 +662,8 @@ static void register_disk(struct device *parent, struct gendisk *disk,
 	 */
 	pm_runtime_set_memalloc_noio(ddev, true);
 
-	disk->part0.bdev->bd_holder_dir =
-			kobject_create_and_add("holders", &ddev->kobj);
+	disk->part0->bd_holder_dir =
+		kobject_create_and_add("holders", &ddev->kobj);
 	disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
 
 	if (disk->flags & GENHD_FL_HIDDEN) {
@@ -738,7 +729,7 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
 
 	disk->flags |= GENHD_FL_UP;
 
-	retval = blk_alloc_devt(&disk->part0, &devt);
+	retval = blk_alloc_devt(disk->part0->bd_part, &devt);
 	if (retval) {
 		WARN_ON(1);
 		return;
@@ -765,7 +756,7 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
 		ret = bdi_register(bdi, "%u:%u", MAJOR(devt), MINOR(devt));
 		WARN_ON(ret);
 		bdi_set_owner(bdi, dev);
-		bdev_add(disk->part0.bdev, devt);
+		bdev_add(disk->part0, devt);
 	}
 	register_disk(parent, disk, groups);
 	if (register_queue)
@@ -872,11 +863,11 @@ void del_gendisk(struct gendisk *disk)
 
 	blk_unregister_queue(disk);
 
-	kobject_put(disk->part0.bdev->bd_holder_dir);
+	kobject_put(disk->part0->bd_holder_dir);
 	kobject_put(disk->slave_dir);
 
-	part_stat_set_all(&disk->part0, 0);
-	disk->part0.bdev->bd_stamp = 0;
+	part_stat_set_all(disk->part0->bd_part, 0);
+	disk->part0->bd_stamp = 0;
 	if (!sysfs_deprecated)
 		sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
 	pm_runtime_set_memalloc_noio(disk_to_dev(disk), false);
@@ -989,7 +980,7 @@ void __init printk_all_partitions(void)
 		 */
 		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
 		while ((part = disk_part_iter_next(&piter))) {
-			bool is_part0 = part == &disk->part0;
+			bool is_part0 = part == disk->part0->bd_part;
 
 			printk("%s%s %10llu %s %s", is_part0 ? "" : "  ",
 			       bdevt_str(part_devt(part), devt_buf),
@@ -1444,7 +1435,7 @@ static void disk_release(struct device *dev)
 	disk_release_events(disk);
 	kfree(disk->random);
 	disk_replace_part_tbl(disk, NULL);
-	hd_free_part(&disk->part0);
+	bdput(disk->part0);
 	if (disk->queue)
 		blk_put_queue(disk->queue);
 	kfree_rcu(disk, rcu);
@@ -1610,8 +1601,8 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
 	if (!disk)
 		return NULL;
 
-	disk->part0.bdev = bdev_alloc(disk, 0);
-	if (!disk->part0.bdev)
+	disk->part0 = bdev_alloc(disk, 0);
+	if (!disk->part0)
 		goto out_free_disk;
 
 	disk->node_id = node_id;
@@ -1619,10 +1610,7 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
 		goto out_bdput;
 
 	ptbl = rcu_dereference_protected(disk->part_tbl, 1);
-	rcu_assign_pointer(ptbl->part[0], &disk->part0);
-
-	if (hd_ref_init(&disk->part0))
-		goto out_bdput;
+	rcu_assign_pointer(ptbl->part[0], disk->part0->bd_part);
 
 	disk->minors = minors;
 	rand_initialize_disk(disk);
@@ -1632,7 +1620,7 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
 	return disk;
 
 out_bdput:
-	bdput(disk->part0.bdev);
+	bdput(disk->part0);
 out_free_disk:
 	kfree(disk);
 	return NULL;
@@ -1671,9 +1659,9 @@ void set_disk_ro(struct gendisk *disk, int flag)
 	struct disk_part_iter piter;
 	struct hd_struct *part;
 
-	if (disk->part0.bdev->bd_read_only != flag) {
+	if (disk->part0->bd_read_only != flag) {
 		set_disk_ro_uevent(disk, flag);
-		disk->part0.bdev->bd_read_only = flag;
+		disk->part0->bd_read_only = flag;
 	}
 
 	disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
diff --git a/block/partitions/core.c b/block/partitions/core.c
index fd00428e437a63..4b0352cb29e132 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -265,9 +265,9 @@ static const struct attribute_group *part_attr_groups[] = {
 static void part_release(struct device *dev)
 {
 	struct hd_struct *p = dev_to_part(dev);
+
 	blk_free_devt(dev->devt);
-	hd_free_part(p);
-	kfree(p);
+	bdput(p->bdev);
 }
 
 static int part_uevent(struct device *dev, struct kobj_uevent_env *env)
@@ -288,46 +288,6 @@ struct device_type part_type = {
 	.uevent		= part_uevent,
 };
 
-static void hd_struct_free_work(struct work_struct *work)
-{
-	struct hd_struct *part =
-		container_of(to_rcu_work(work), struct hd_struct, rcu_work);
-	struct gendisk *disk = part_to_disk(part);
-
-	/*
-	 * Release the disk reference acquired in delete_partition here.
-	 * We can't release it in hd_struct_free because the final put_device
-	 * needs process context and thus can't be run directly from a
-	 * percpu_ref ->release handler.
-	 */
-	put_device(disk_to_dev(disk));
-
-	part->bdev->bd_start_sect = 0;
-	bdev_set_nr_sectors(part->bdev, 0);
-	part_stat_set_all(part, 0);
-	put_device(part_to_dev(part));
-}
-
-static void hd_struct_free(struct percpu_ref *ref)
-{
-	struct hd_struct *part = container_of(ref, struct hd_struct, ref);
-	struct gendisk *disk = part_to_disk(part);
-	struct disk_part_tbl *ptbl =
-		rcu_dereference_protected(disk->part_tbl, 1);
-
-	rcu_assign_pointer(ptbl->last_lookup, NULL);
-
-	INIT_RCU_WORK(&part->rcu_work, hd_struct_free_work);
-	queue_rcu_work(system_wq, &part->rcu_work);
-}
-
-int hd_ref_init(struct hd_struct *part)
-{
-	if (percpu_ref_init(&part->ref, hd_struct_free, 0, GFP_KERNEL))
-		return -ENOMEM;
-	return 0;
-}
-
 /*
  * Must be called either with bd_mutex held, before a disk can be opened or
  * after all disk users are gone.
@@ -342,8 +302,8 @@ void delete_partition(struct hd_struct *part)
 	 * ->part_tbl is referenced in this part's release handler, so
 	 *  we have to hold the disk device
 	 */
-	get_device(disk_to_dev(disk));
 	rcu_assign_pointer(ptbl->part[part->partno], NULL);
+	rcu_assign_pointer(ptbl->last_lookup, NULL);
 	kobject_put(part->bdev->bd_holder_dir);
 	device_del(part_to_dev(part));
 
@@ -353,7 +313,7 @@ void delete_partition(struct hd_struct *part)
 	 */
 	remove_inode_hash(part->bdev->bd_inode);
 
-	percpu_ref_kill(&part->ref);
+	put_device(part_to_dev(part));
 }
 
 static ssize_t whole_disk_show(struct device *dev,
@@ -406,15 +366,11 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 	if (ptbl->part[partno])
 		return ERR_PTR(-EBUSY);
 
-	p = kzalloc(sizeof(*p), GFP_KERNEL);
-	if (!p)
-		return ERR_PTR(-EBUSY);
-
 	bdev = bdev_alloc(disk, partno);
 	if (!bdev)
-		goto out_free;
-	p->bdev = bdev;
+		return ERR_PTR(-ENOMEM);
 
+	p = bdev->bd_part;
 	pdev = part_to_dev(p);
 
 	bdev->bd_start_sect = start;
@@ -463,13 +419,6 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 			goto out_del;
 	}
 
-	err = hd_ref_init(p);
-	if (err) {
-		if (flags & ADDPART_FLAG_WHOLEDISK)
-			goto out_remove_file;
-		goto out_del;
-	}
-
 	/* everything is up and running, commence */
 	bdev_add(bdev, devt);
 	rcu_assign_pointer(ptbl->part[partno], p);
@@ -481,11 +430,7 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 
 out_bdput:
 	bdput(bdev);
-out_free:
-	kfree(p);
 	return ERR_PTR(err);
-out_remove_file:
-	device_remove_file(pdev, &dev_attr_whole_disk);
 out_del:
 	kobject_put(bdev->bd_holder_dir);
 	device_del(pdev);
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index dc333dbe523281..9e5c2fdfda3629 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -2802,7 +2802,7 @@ bool drbd_rs_c_min_rate_throttle(struct drbd_device *device)
 	if (c_min_rate == 0)
 		return false;
 
-	curr_events = (int)part_stat_read_accum(&disk->part0, sectors) -
+	curr_events = (int)part_stat_read_accum(disk->part0->bd_part, sectors) -
 			atomic_read(&device->rs_sect_ev);
 
 	if (atomic_read(&device->ap_actlog_cnt)
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index ba56f3f05312f0..343f56b86bb766 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -1678,7 +1678,8 @@ void drbd_rs_controller_reset(struct drbd_device *device)
 	atomic_set(&device->rs_sect_in, 0);
 	atomic_set(&device->rs_sect_ev, 0);
 	device->rs_in_flight = 0;
-	device->rs_last_events = (int)part_stat_read_accum(&disk->part0, sectors);
+	device->rs_last_events =
+		(int)part_stat_read_accum(disk->part0->bd_part, sectors);
 
 	/* Updating the RCU protected object in place is necessary since
 	   this function gets called from atomic context.
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 88baa6158eaee1..153858734cd47d 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1687,7 +1687,7 @@ static void zram_reset_device(struct zram *zram)
 	zram->disksize = 0;
 
 	set_capacity_and_notify(zram->disk, 0);
-	part_stat_set_all(&zram->disk->part0, 0);
+	part_stat_set_all(zram->disk->part0->bd_part, 0);
 
 	up_write(&zram->init_lock);
 	/* I/O operation under all of CPU are done so let's free */
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 48051db006f30c..1b2db4d530ea71 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1607,7 +1607,7 @@ static blk_qc_t __split_and_process_bio(struct mapped_device *md,
 				 * (by eliminating DM's splitting and just using bio_split)
 				 */
 				part_stat_lock();
-				__dm_part_stat_sub(&dm_disk(md)->part0,
+				__dm_part_stat_sub(dm_disk(md)->part0->bd_part,
 						   sectors[op_stat_group(bio_op(bio))], ci.sector_count);
 				part_stat_unlock();
 
@@ -2242,7 +2242,7 @@ EXPORT_SYMBOL_GPL(dm_put);
 static bool md_in_flight_bios(struct mapped_device *md)
 {
 	int cpu;
-	struct hd_struct *part = &dm_disk(md)->part0;
+	struct hd_struct *part = dm_disk(md)->part0->bd_part;
 	long sum = 0;
 
 	for_each_possible_cpu(cpu) {
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 7ce6047c856ea2..3696c2d77a4dd7 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8441,7 +8441,7 @@ static int is_mddev_idle(struct mddev *mddev, int init)
 	rcu_read_lock();
 	rdev_for_each_rcu(rdev, mddev) {
 		struct gendisk *disk = rdev->bdev->bd_disk;
-		curr_events = (int)part_stat_read_accum(&disk->part0, sectors) -
+		curr_events = (int)part_stat_read_accum(disk->part0->bd_part, sectors) -
 			      atomic_read(&disk->sync_io);
 		/* sync IO will cause sync_io to increase before the disk_stats
 		 * as sync_io is counted when a request starts, and
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 0b8d6009486643..1538b20ca4bd43 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -39,6 +39,7 @@
 
 struct bdev_inode {
 	struct block_device bdev;
+	struct hd_struct hd;
 	struct inode vfs_inode;
 };
 
@@ -885,6 +886,9 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
 		iput(inode);
 		return NULL;
 	}
+	bdev->bd_part = &BDEV_I(inode)->hd;
+	memset(bdev->bd_part, 0, sizeof(*bdev->bd_part));
+	bdev->bd_part->bdev = bdev;
 	return bdev;
 }
 
@@ -1275,15 +1279,10 @@ EXPORT_SYMBOL_GPL(bdev_disk_changed);
 static int __blkdev_get(struct block_device *bdev, fmode_t mode)
 {
 	struct gendisk *disk = bdev->bd_disk;
-	int ret;
+	int ret = 0;
 
 	if (!bdev->bd_openers) {
 		if (!bdev_is_partition(bdev)) {
-			ret = -ENXIO;
-			bdev->bd_part = disk_get_part(disk, 0);
-			if (!bdev->bd_part)
-				goto out_clear;
-
 			ret = 0;
 			if (disk->fops->open)
 				ret = disk->fops->open(bdev, mode);
@@ -1302,7 +1301,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode)
 				bdev_disk_changed(bdev, ret == -ENOMEDIUM);
 
 			if (ret)
-				goto out_clear;
+				return ret;
 		} else {
 			struct block_device *whole = bdget_disk(disk, 0);
 
@@ -1311,16 +1310,14 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode)
 			if (ret) {
 				mutex_unlock(&whole->bd_mutex);
 				bdput(whole);
-				goto out_clear;
+				return ret;
 			}
 			whole->bd_part_count++;
 			mutex_unlock(&whole->bd_mutex);
 
-			bdev->bd_part = disk_get_part(disk, bdev->bd_partno);
 			if (!bdev_nr_sectors(bdev)) {
 				__blkdev_put(whole, mode, 1);
-				ret = -ENXIO;
-				goto out_clear;
+				return -ENXIO;
 			}
 			set_init_blocksize(bdev);
 		}
@@ -1329,7 +1326,6 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode)
 			bdev->bd_bdi = bdi_get(disk->queue->backing_dev_info);
 	} else {
 		if (!bdev_is_partition(bdev)) {
-			ret = 0;
 			if (bdev->bd_disk->fops->open)
 				ret = bdev->bd_disk->fops->open(bdev, mode);
 			/* the same as first opener case, read comment there */
@@ -1342,11 +1338,6 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode)
 	}
 	bdev->bd_openers++;
 	return 0;
-
- out_clear:
-	disk_put_part(bdev->bd_part);
-	bdev->bd_part = NULL;
-	return ret;
 }
 
 static struct block_device *get_bdev_disk_and_module(dev_t dev)
@@ -1569,18 +1560,12 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
 		sync_blockdev(bdev);
 		kill_bdev(bdev);
 		bdev_write_inode(bdev);
-
-		if (!bdev_is_partition(bdev) && disk->fops->release)
-			disk->fops->release(disk, mode);
-
-		disk_put_part(bdev->bd_part);
-		bdev->bd_part = NULL;
 		if (bdev_is_partition(bdev))
 			victim = bdev_whole(bdev);
-	} else {
-		if (!bdev_is_partition(bdev) && disk->fops->release)
-			disk->fops->release(disk, mode);
 	}
+
+	if (!bdev_is_partition(bdev) && disk->fops->release)
+		disk->fops->release(disk, mode);
 	mutex_unlock(&bdev->bd_mutex);
 	bdput(bdev);
 	if (victim)
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 758cf71c9aa2a6..6edea5c1625909 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -59,7 +59,7 @@ struct block_device {
 } __randomize_layout;
 
 #define bdev_whole(_bdev) \
-	((_bdev)->bd_disk->part0.bdev)
+	((_bdev)->bd_disk->part0)
 
 #define bdev_kobj(_bdev) \
 	(&part_to_dev((_bdev)->bd_part)->kobj)
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 08d00b526b0a3b..6e16c264439bdb 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -19,11 +19,12 @@
 #include <linux/blk_types.h>
 #include <asm/local.h>
 
-#define dev_to_disk(device)	container_of((device), struct gendisk, part0.__dev)
 #define dev_to_part(device)	container_of((device), struct hd_struct, __dev)
-#define disk_to_dev(disk)	(&(disk)->part0.__dev)
 #define part_to_dev(part)	(&((part)->__dev))
 
+#define dev_to_disk(device)	(dev_to_part(device)->bdev->bd_disk)
+#define disk_to_dev(disk)	(part_to_dev((disk)->part0->bd_part))
+
 extern const struct device_type disk_type;
 extern struct device_type part_type;
 extern struct class block_class;
@@ -51,12 +52,9 @@ struct partition_meta_info {
 };
 
 struct hd_struct {
-	struct percpu_ref ref;
-
 	struct block_device *bdev;
 	struct device __dev;
 	int partno;
-	struct rcu_work rcu_work;
 };
 
 /**
@@ -168,7 +166,7 @@ struct gendisk {
 	 * helpers.
 	 */
 	struct disk_part_tbl __rcu *part_tbl;
-	struct hd_struct part0;
+	struct block_device *part0;
 
 	const struct block_device_operations *fops;
 	struct request_queue *queue;
@@ -279,7 +277,7 @@ extern void set_disk_ro(struct gendisk *disk, int flag);
 
 static inline int get_disk_ro(struct gendisk *disk)
 {
-	return disk->part0.bdev->bd_read_only;
+	return disk->part0->bd_read_only;
 }
 
 extern void disk_block_events(struct gendisk *disk);
@@ -303,7 +301,7 @@ static inline sector_t bdev_nr_sectors(struct block_device *bdev)
 
 static inline sector_t get_capacity(struct gendisk *disk)
 {
-	return bdev_nr_sectors(disk->part0.bdev);
+	return bdev_nr_sectors(disk->part0);
 }
 
 int bdev_disk_changed(struct block_device *bdev, bool invalidate);
diff --git a/include/linux/part_stat.h b/include/linux/part_stat.h
index 87ad60106e1db0..680de036691ef9 100644
--- a/include/linux/part_stat.h
+++ b/include/linux/part_stat.h
@@ -59,8 +59,8 @@ static inline void part_stat_set_all(struct hd_struct *part, int value)
 #define part_stat_add(part, field, addnd)	do {			\
 	__part_stat_add((part), field, addnd);				\
 	if ((part)->partno)						\
-		__part_stat_add(&part_to_disk((part))->part0,		\
-				field, addnd);				\
+		__part_stat_add(part_to_disk((part))->part0->bd_part,	\
+			field, addnd); \
 } while (0)
 
 #define part_stat_dec(part, field)					\
-- 
2.29.2

--
dm-devel mailing list
dm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel


^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 38/45] block: switch partition lookup to use struct block_device
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (36 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 37/45] block: allocate struct hd_struct as part of struct bdev_inode Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 13:32   ` Coly Li
  2020-11-25  6:11   ` Chao Yu
  2020-11-24 13:27 ` [dm-devel] [PATCH 39/45] block: remove the partno field from struct hd_struct Christoph Hellwig
                   ` (6 subsequent siblings)
  44 siblings, 2 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Use struct block_device to lookup partitions on a disk.  This removes
all usage of struct hd_struct from the I/O path, and this allows removing
the percpu refcount in struct hd_struct.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/bio.c                        |  4 +-
 block/blk-core.c                   | 66 ++++++++++++++----------------
 block/blk-flush.c                  |  2 +-
 block/blk-mq.c                     |  9 ++--
 block/blk-mq.h                     |  7 ++--
 block/blk.h                        |  4 +-
 block/genhd.c                      | 56 +++++++++++++------------
 block/partitions/core.c            |  7 +---
 drivers/block/drbd/drbd_receiver.c |  2 +-
 drivers/block/drbd/drbd_worker.c   |  2 +-
 drivers/block/zram/zram_drv.c      |  2 +-
 drivers/md/bcache/request.c        |  4 +-
 drivers/md/dm.c                    |  4 +-
 drivers/md/md.c                    |  4 +-
 drivers/nvme/target/admin-cmd.c    | 20 ++++-----
 fs/ext4/super.c                    | 18 +++-----
 fs/ext4/sysfs.c                    | 10 +----
 fs/f2fs/f2fs.h                     |  2 +-
 fs/f2fs/super.c                    |  6 +--
 include/linux/blkdev.h             |  8 ++--
 include/linux/genhd.h              |  4 +-
 include/linux/part_stat.h          | 17 ++++----
 22 files changed, 120 insertions(+), 138 deletions(-)

diff --git a/block/bio.c b/block/bio.c
index 669bb47a31988e..ebb18136b86f2f 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -608,12 +608,12 @@ void bio_truncate(struct bio *bio, unsigned new_size)
 void guard_bio_eod(struct bio *bio)
 {
 	sector_t maxsector;
-	struct hd_struct *part;
+	struct block_device *part;
 
 	rcu_read_lock();
 	part = __disk_get_part(bio->bi_disk, bio->bi_partno);
 	if (part)
-		maxsector = bdev_nr_sectors(part->bdev);
+		maxsector = bdev_nr_sectors(part);
 	else	
 		maxsector = get_capacity(bio->bi_disk);
 	rcu_read_unlock();
diff --git a/block/blk-core.c b/block/blk-core.c
index 9ea70275fc1cfe..cee568389b7e11 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -666,10 +666,9 @@ static int __init setup_fail_make_request(char *str)
 }
 __setup("fail_make_request=", setup_fail_make_request);
 
-static bool should_fail_request(struct hd_struct *part, unsigned int bytes)
+static bool should_fail_request(struct block_device *part, unsigned int bytes)
 {
-	return part->bdev->bd_make_it_fail &&
-		should_fail(&fail_make_request, bytes);
+	return part->bd_make_it_fail && should_fail(&fail_make_request, bytes);
 }
 
 static int __init fail_make_request_debugfs(void)
@@ -684,7 +683,7 @@ late_initcall(fail_make_request_debugfs);
 
 #else /* CONFIG_FAIL_MAKE_REQUEST */
 
-static inline bool should_fail_request(struct hd_struct *part,
+static inline bool should_fail_request(struct block_device *part,
 					unsigned int bytes)
 {
 	return false;
@@ -692,11 +691,11 @@ static inline bool should_fail_request(struct hd_struct *part,
 
 #endif /* CONFIG_FAIL_MAKE_REQUEST */
 
-static inline bool bio_check_ro(struct bio *bio, struct hd_struct *part)
+static inline bool bio_check_ro(struct bio *bio, struct block_device *part)
 {
 	const int op = bio_op(bio);
 
-	if (part->bdev->bd_read_only && op_is_write(op)) {
+	if (part->bd_read_only && op_is_write(op)) {
 		char b[BDEVNAME_SIZE];
 
 		if (op_is_flush(bio->bi_opf) && !bio_sectors(bio))
@@ -704,7 +703,7 @@ static inline bool bio_check_ro(struct bio *bio, struct hd_struct *part)
 
 		WARN_ONCE(1,
 		       "Trying to write to read-only block-device %s (partno %d)\n",
-			bio_devname(bio, b), part->partno);
+			bio_devname(bio, b), part->bd_partno);
 		/* Older lvm-tools actually trigger this */
 		return false;
 	}
@@ -714,8 +713,7 @@ static inline bool bio_check_ro(struct bio *bio, struct hd_struct *part)
 
 static noinline int should_fail_bio(struct bio *bio)
 {
-	if (should_fail_request(bio->bi_disk->part0->bd_part,
-			bio->bi_iter.bi_size))
+	if (should_fail_request(bio->bi_disk->part0, bio->bi_iter.bi_size))
 		return -EIO;
 	return 0;
 }
@@ -744,7 +742,7 @@ static inline int bio_check_eod(struct bio *bio, sector_t maxsector)
  */
 static inline int blk_partition_remap(struct bio *bio)
 {
-	struct hd_struct *p;
+	struct block_device *p;
 	int ret = -EIO;
 
 	rcu_read_lock();
@@ -757,12 +755,12 @@ static inline int blk_partition_remap(struct bio *bio)
 		goto out;
 
 	if (bio_sectors(bio)) {
-		if (bio_check_eod(bio, bdev_nr_sectors(p->bdev)))
+		if (bio_check_eod(bio, bdev_nr_sectors(p)))
 			goto out;
-		bio->bi_iter.bi_sector += p->bdev->bd_start_sect;
-		trace_block_bio_remap(bio->bi_disk->queue, bio, part_devt(p),
+		bio->bi_iter.bi_sector += p->bd_start_sect;
+		trace_block_bio_remap(bio->bi_disk->queue, bio, p->bd_dev,
 				      bio->bi_iter.bi_sector -
-				      p->bdev->bd_start_sect);
+				      p->bd_start_sect);
 	}
 	bio->bi_partno = 0;
 	ret = 0;
@@ -832,7 +830,7 @@ static noinline_for_stack bool submit_bio_checks(struct bio *bio)
 		if (unlikely(blk_partition_remap(bio)))
 			goto end_io;
 	} else {
-		if (unlikely(bio_check_ro(bio, bio->bi_disk->part0->bd_part)))
+		if (unlikely(bio_check_ro(bio, bio->bi_disk->part0)))
 			goto end_io;
 		if (unlikely(bio_check_eod(bio, get_capacity(bio->bi_disk))))
 			goto end_io;
@@ -1204,7 +1202,7 @@ blk_status_t blk_insert_cloned_request(struct request_queue *q, struct request *
 		return ret;
 
 	if (rq->rq_disk &&
-	    should_fail_request(rq->rq_disk->part0->bd_part, blk_rq_bytes(rq)))
+	    should_fail_request(rq->rq_disk->part0, blk_rq_bytes(rq)))
 		return BLK_STS_IOERR;
 
 	if (blk_crypto_insert_cloned_request(rq))
@@ -1263,17 +1261,18 @@ unsigned int blk_rq_err_bytes(const struct request *rq)
 }
 EXPORT_SYMBOL_GPL(blk_rq_err_bytes);
 
-static void update_io_ticks(struct hd_struct *part, unsigned long now, bool end)
+static void update_io_ticks(struct block_device *part, unsigned long now,
+		bool end)
 {
 	unsigned long stamp;
 again:
-	stamp = READ_ONCE(part->bdev->bd_stamp);
+	stamp = READ_ONCE(part->bd_stamp);
 	if (unlikely(stamp != now)) {
-		if (likely(cmpxchg(&part->bdev->bd_stamp, stamp, now) == stamp))
+		if (likely(cmpxchg(&part->bd_stamp, stamp, now) == stamp))
 			__part_stat_add(part, io_ticks, end ? now - stamp : 1);
 	}
-	if (part->partno) {
-		part = part_to_disk(part)->part0->bd_part;
+	if (part->bd_partno) {
+		part = bdev_whole(part);
 		goto again;
 	}
 }
@@ -1282,11 +1281,9 @@ static void blk_account_io_completion(struct request *req, unsigned int bytes)
 {
 	if (req->part && blk_do_io_stat(req)) {
 		const int sgrp = op_stat_group(req_op(req));
-		struct hd_struct *part;
 
 		part_stat_lock();
-		part = req->part;
-		part_stat_add(part, sectors[sgrp], bytes >> 9);
+		part_stat_add(req->part, sectors[sgrp], bytes >> 9);
 		part_stat_unlock();
 	}
 }
@@ -1301,14 +1298,11 @@ void blk_account_io_done(struct request *req, u64 now)
 	if (req->part && blk_do_io_stat(req) &&
 	    !(req->rq_flags & RQF_FLUSH_SEQ)) {
 		const int sgrp = op_stat_group(req_op(req));
-		struct hd_struct *part;
 
 		part_stat_lock();
-		part = req->part;
-
-		update_io_ticks(part, jiffies, true);
-		part_stat_inc(part, ios[sgrp]);
-		part_stat_add(part, nsecs[sgrp], now - req->start_time_ns);
+		update_io_ticks(req->part, jiffies, true);
+		part_stat_inc(req->part, ios[sgrp]);
+		part_stat_add(req->part, nsecs[sgrp], now - req->start_time_ns);
 		part_stat_unlock();
 	}
 }
@@ -1325,7 +1319,7 @@ void blk_account_io_start(struct request *rq)
 	part_stat_unlock();
 }
 
-static unsigned long __part_start_io_acct(struct hd_struct *part,
+static unsigned long __part_start_io_acct(struct block_device *part,
 					  unsigned int sectors, unsigned int op)
 {
 	const int sgrp = op_stat_group(op);
@@ -1341,7 +1335,7 @@ static unsigned long __part_start_io_acct(struct hd_struct *part,
 	return now;
 }
 
-unsigned long part_start_io_acct(struct gendisk *disk, struct hd_struct **part,
+unsigned long part_start_io_acct(struct gendisk *disk, struct block_device **part,
 				 struct bio *bio)
 {
 	*part = disk_map_sector_rcu(disk, bio->bi_iter.bi_sector);
@@ -1353,11 +1347,11 @@ EXPORT_SYMBOL_GPL(part_start_io_acct);
 unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors,
 				 unsigned int op)
 {
-	return __part_start_io_acct(disk->part0->bd_part, sectors, op);
+	return __part_start_io_acct(disk->part0, sectors, op);
 }
 EXPORT_SYMBOL(disk_start_io_acct);
 
-static void __part_end_io_acct(struct hd_struct *part, unsigned int op,
+static void __part_end_io_acct(struct block_device *part, unsigned int op,
 			       unsigned long start_time)
 {
 	const int sgrp = op_stat_group(op);
@@ -1371,7 +1365,7 @@ static void __part_end_io_acct(struct hd_struct *part, unsigned int op,
 	part_stat_unlock();
 }
 
-void part_end_io_acct(struct hd_struct *part, struct bio *bio,
+void part_end_io_acct(struct block_device *part, struct bio *bio,
 		      unsigned long start_time)
 {
 	__part_end_io_acct(part, bio_op(bio), start_time);
@@ -1381,7 +1375,7 @@ EXPORT_SYMBOL_GPL(part_end_io_acct);
 void disk_end_io_acct(struct gendisk *disk, unsigned int op,
 		      unsigned long start_time)
 {
-	__part_end_io_acct(disk->part0->bd_part, op, start_time);
+	__part_end_io_acct(disk->part0, op, start_time);
 }
 EXPORT_SYMBOL(disk_end_io_acct);
 
diff --git a/block/blk-flush.c b/block/blk-flush.c
index fcd0a60574dff8..9507dcdd58814c 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -139,7 +139,7 @@ static void blk_flush_queue_rq(struct request *rq, bool add_front)
 
 static void blk_account_io_flush(struct request *rq)
 {
-	struct hd_struct *part = rq->rq_disk->part0->bd_part;
+	struct block_device *part = rq->rq_disk->part0;
 
 	part_stat_lock();
 	part_stat_inc(part, ios[STAT_FLUSH]);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 55bcee5dc0320c..a2593748fa5342 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -95,7 +95,7 @@ static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx,
 }
 
 struct mq_inflight {
-	struct hd_struct *part;
+	struct block_device *part;
 	unsigned int inflight[2];
 };
 
@@ -111,7 +111,8 @@ static bool blk_mq_check_inflight(struct blk_mq_hw_ctx *hctx,
 	return true;
 }
 
-unsigned int blk_mq_in_flight(struct request_queue *q, struct hd_struct *part)
+unsigned int blk_mq_in_flight(struct request_queue *q,
+		struct block_device *part)
 {
 	struct mq_inflight mi = { .part = part };
 
@@ -120,8 +121,8 @@ unsigned int blk_mq_in_flight(struct request_queue *q, struct hd_struct *part)
 	return mi.inflight[0] + mi.inflight[1];
 }
 
-void blk_mq_in_flight_rw(struct request_queue *q, struct hd_struct *part,
-			 unsigned int inflight[2])
+void blk_mq_in_flight_rw(struct request_queue *q, struct block_device *part,
+		unsigned int inflight[2])
 {
 	struct mq_inflight mi = { .part = part };
 
diff --git a/block/blk-mq.h b/block/blk-mq.h
index a52703c98b7736..c696515766c780 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -182,9 +182,10 @@ static inline bool blk_mq_hw_queue_mapped(struct blk_mq_hw_ctx *hctx)
 	return hctx->nr_ctx && hctx->tags;
 }
 
-unsigned int blk_mq_in_flight(struct request_queue *q, struct hd_struct *part);
-void blk_mq_in_flight_rw(struct request_queue *q, struct hd_struct *part,
-			 unsigned int inflight[2]);
+unsigned int blk_mq_in_flight(struct request_queue *q,
+		struct block_device *part);
+void blk_mq_in_flight_rw(struct request_queue *q, struct block_device *part,
+		unsigned int inflight[2]);
 
 static inline void blk_mq_put_dispatch_budget(struct request_queue *q)
 {
diff --git a/block/blk.h b/block/blk.h
index 32ac41f7557fcc..d5bf8f3a078186 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -215,7 +215,7 @@ static inline void elevator_exit(struct request_queue *q,
 	__elevator_exit(q, e);
 }
 
-struct hd_struct *__disk_get_part(struct gendisk *disk, int partno);
+struct block_device *__disk_get_part(struct gendisk *disk, int partno);
 
 ssize_t part_size_show(struct device *dev, struct device_attribute *attr,
 		char *buf);
@@ -348,7 +348,7 @@ void blk_queue_free_zone_bitmaps(struct request_queue *q);
 static inline void blk_queue_free_zone_bitmaps(struct request_queue *q) {}
 #endif
 
-struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector);
+struct block_device *disk_map_sector_rcu(struct gendisk *disk, sector_t sector);
 
 int blk_alloc_devt(struct hd_struct *part, dev_t *devt);
 void blk_free_devt(dev_t devt);
diff --git a/block/genhd.c b/block/genhd.c
index 3bbf6d3a69ec63..197120c0c60f23 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -116,7 +116,7 @@ static void part_stat_read_all(struct hd_struct *part, struct disk_stats *stat)
 	}
 }
 
-static unsigned int part_in_flight(struct hd_struct *part)
+static unsigned int part_in_flight(struct block_device *part)
 {
 	unsigned int inflight = 0;
 	int cpu;
@@ -131,7 +131,8 @@ static unsigned int part_in_flight(struct hd_struct *part)
 	return inflight;
 }
 
-static void part_in_flight_rw(struct hd_struct *part, unsigned int inflight[2])
+static void part_in_flight_rw(struct block_device *part,
+		unsigned int inflight[2])
 {
 	int cpu;
 
@@ -147,7 +148,7 @@ static void part_in_flight_rw(struct hd_struct *part, unsigned int inflight[2])
 		inflight[1] = 0;
 }
 
-struct hd_struct *__disk_get_part(struct gendisk *disk, int partno)
+struct block_device *__disk_get_part(struct gendisk *disk, int partno)
 {
 	struct disk_part_tbl *ptbl = rcu_dereference(disk->part_tbl);
 
@@ -172,15 +173,18 @@ struct hd_struct *__disk_get_part(struct gendisk *disk, int partno)
  */
 struct hd_struct *disk_get_part(struct gendisk *disk, int partno)
 {
-	struct hd_struct *part;
+	struct block_device *part;
 
 	rcu_read_lock();
 	part = __disk_get_part(disk, partno);
-	if (part)
-		get_device(part_to_dev(part));
-	rcu_read_unlock();
+	if (!part) {
+		rcu_read_unlock();
+		return NULL;
+	}
 
-	return part;
+	get_device(part_to_dev(part->bd_part));
+	rcu_read_unlock();
+	return part->bd_part;
 }
 
 /**
@@ -254,19 +258,19 @@ struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter)
 
 	/* iterate to the next partition */
 	for (; piter->idx != end; piter->idx += inc) {
-		struct hd_struct *part;
+		struct block_device *part;
 
 		part = rcu_dereference(ptbl->part[piter->idx]);
 		if (!part)
 			continue;
-		if (!bdev_nr_sectors(part->bdev) &&
+		if (!bdev_nr_sectors(part) &&
 		    !(piter->flags & DISK_PITER_INCL_EMPTY) &&
 		    !(piter->flags & DISK_PITER_INCL_EMPTY_PART0 &&
 		      piter->idx == 0))
 			continue;
 
-		get_device(part_to_dev(part));
-		piter->part = part;
+		get_device(part_to_dev(part->bd_part));
+		piter->part = part->bd_part;
 		piter->idx += inc;
 		break;
 	}
@@ -293,10 +297,10 @@ void disk_part_iter_exit(struct disk_part_iter *piter)
 }
 EXPORT_SYMBOL_GPL(disk_part_iter_exit);
 
-static inline int sector_in_part(struct hd_struct *part, sector_t sector)
+static inline int sector_in_part(struct block_device *part, sector_t sector)
 {
-	return part->bdev->bd_start_sect <= sector &&
-		sector < part->bdev->bd_start_sect + bdev_nr_sectors(part->bdev);
+	return part->bd_start_sect <= sector &&
+		sector < part->bd_start_sect + bdev_nr_sectors(part);
 }
 
 /**
@@ -314,10 +318,10 @@ static inline int sector_in_part(struct hd_struct *part, sector_t sector)
  * Found partition on success, part0 is returned if no partition matches
  * or the matched partition is being deleted.
  */
-struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector)
+struct block_device *disk_map_sector_rcu(struct gendisk *disk, sector_t sector)
 {
 	struct disk_part_tbl *ptbl;
-	struct hd_struct *part;
+	struct block_device *part;
 	int i;
 
 	rcu_read_lock();
@@ -336,7 +340,7 @@ struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector)
 		}
 	}
 
-	part = disk->part0->bd_part;
+	part = disk->part0;
 out_unlock:
 	rcu_read_unlock();
 	return part;
@@ -866,7 +870,7 @@ void del_gendisk(struct gendisk *disk)
 	kobject_put(disk->part0->bd_holder_dir);
 	kobject_put(disk->slave_dir);
 
-	part_stat_set_all(disk->part0->bd_part, 0);
+	part_stat_set_all(disk->part0, 0);
 	disk->part0->bd_stamp = 0;
 	if (!sysfs_deprecated)
 		sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
@@ -1173,9 +1177,9 @@ ssize_t part_stat_show(struct device *dev,
 
 	part_stat_read_all(p, &stat);
 	if (queue_is_mq(q))
-		inflight = blk_mq_in_flight(q, p);
+		inflight = blk_mq_in_flight(q, p->bdev);
 	else
-		inflight = part_in_flight(p);
+		inflight = part_in_flight(p->bdev);
 
 	return sprintf(buf,
 		"%8lu %8lu %8llu %8u "
@@ -1215,9 +1219,9 @@ ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr,
 	unsigned int inflight[2];
 
 	if (queue_is_mq(q))
-		blk_mq_in_flight_rw(q, p, inflight);
+		blk_mq_in_flight_rw(q, p->bdev, inflight);
 	else
-		part_in_flight_rw(p, inflight);
+		part_in_flight_rw(p->bdev, inflight);
 
 	return sprintf(buf, "%8u %8u\n", inflight[0], inflight[1]);
 }
@@ -1490,9 +1494,9 @@ static int diskstats_show(struct seq_file *seqf, void *v)
 	while ((hd = disk_part_iter_next(&piter))) {
 		part_stat_read_all(hd, &stat);
 		if (queue_is_mq(gp->queue))
-			inflight = blk_mq_in_flight(gp->queue, hd);
+			inflight = blk_mq_in_flight(gp->queue, hd->bdev);
 		else
-			inflight = part_in_flight(hd);
+			inflight = part_in_flight(hd->bdev);
 
 		seq_printf(seqf, "%4d %7d %s "
 			   "%lu %lu %lu %u "
@@ -1610,7 +1614,7 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
 		goto out_bdput;
 
 	ptbl = rcu_dereference_protected(disk->part_tbl, 1);
-	rcu_assign_pointer(ptbl->part[0], disk->part0->bd_part);
+	rcu_assign_pointer(ptbl->part[0], disk->part0);
 
 	disk->minors = minors;
 	rand_initialize_disk(disk);
diff --git a/block/partitions/core.c b/block/partitions/core.c
index 4b0352cb29e132..8beab9e7727e27 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -298,12 +298,9 @@ void delete_partition(struct hd_struct *part)
 	struct disk_part_tbl *ptbl =
 		rcu_dereference_protected(disk->part_tbl, 1);
 
-	/*
-	 * ->part_tbl is referenced in this part's release handler, so
-	 *  we have to hold the disk device
-	 */
 	rcu_assign_pointer(ptbl->part[part->partno], NULL);
 	rcu_assign_pointer(ptbl->last_lookup, NULL);
+
 	kobject_put(part->bdev->bd_holder_dir);
 	device_del(part_to_dev(part));
 
@@ -421,7 +418,7 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 
 	/* everything is up and running, commence */
 	bdev_add(bdev, devt);
-	rcu_assign_pointer(ptbl->part[partno], p);
+	rcu_assign_pointer(ptbl->part[partno], bdev);
 
 	/* suppress uevent if the disk suppresses it */
 	if (!dev_get_uevent_suppress(ddev))
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 9e5c2fdfda3629..09c86ef3f0fd93 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -2802,7 +2802,7 @@ bool drbd_rs_c_min_rate_throttle(struct drbd_device *device)
 	if (c_min_rate == 0)
 		return false;
 
-	curr_events = (int)part_stat_read_accum(disk->part0->bd_part, sectors) -
+	curr_events = (int)part_stat_read_accum(disk->part0, sectors) -
 			atomic_read(&device->rs_sect_ev);
 
 	if (atomic_read(&device->ap_actlog_cnt)
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 343f56b86bb766..02044ab7f767d5 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -1679,7 +1679,7 @@ void drbd_rs_controller_reset(struct drbd_device *device)
 	atomic_set(&device->rs_sect_ev, 0);
 	device->rs_in_flight = 0;
 	device->rs_last_events =
-		(int)part_stat_read_accum(disk->part0->bd_part, sectors);
+		(int)part_stat_read_accum(disk->part0, sectors);
 
 	/* Updating the RCU protected object in place is necessary since
 	   this function gets called from atomic context.
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 153858734cd47d..01757f9578dcb8 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1687,7 +1687,7 @@ static void zram_reset_device(struct zram *zram)
 	zram->disksize = 0;
 
 	set_capacity_and_notify(zram->disk, 0);
-	part_stat_set_all(zram->disk->part0->bd_part, 0);
+	part_stat_set_all(zram->disk->part0, 0);
 
 	up_write(&zram->init_lock);
 	/* I/O operation under all of CPU are done so let's free */
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index afac8d07c1bd00..85b1f2a9b72d68 100644
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -475,7 +475,7 @@ struct search {
 	unsigned int		read_dirty_data:1;
 	unsigned int		cache_missed:1;
 
-	struct hd_struct	*part;
+	struct block_device	*part;
 	unsigned long		start_time;
 
 	struct btree_op		op;
@@ -1073,7 +1073,7 @@ struct detached_dev_io_private {
 	unsigned long		start_time;
 	bio_end_io_t		*bi_end_io;
 	void			*bi_private;
-	struct hd_struct	*part;
+	struct block_device	*part;
 };
 
 static void detached_dev_end_io(struct bio *bio)
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 1b2db4d530ea71..176adcff56b380 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1607,7 +1607,7 @@ static blk_qc_t __split_and_process_bio(struct mapped_device *md,
 				 * (by eliminating DM's splitting and just using bio_split)
 				 */
 				part_stat_lock();
-				__dm_part_stat_sub(dm_disk(md)->part0->bd_part,
+				__dm_part_stat_sub(dm_disk(md)->part0,
 						   sectors[op_stat_group(bio_op(bio))], ci.sector_count);
 				part_stat_unlock();
 
@@ -2242,7 +2242,7 @@ EXPORT_SYMBOL_GPL(dm_put);
 static bool md_in_flight_bios(struct mapped_device *md)
 {
 	int cpu;
-	struct hd_struct *part = dm_disk(md)->part0->bd_part;
+	struct block_device *part = dm_disk(md)->part0;
 	long sum = 0;
 
 	for_each_possible_cpu(cpu) {
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 3696c2d77a4dd7..0065736f05b428 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -464,7 +464,7 @@ struct md_io {
 	bio_end_io_t *orig_bi_end_io;
 	void *orig_bi_private;
 	unsigned long start_time;
-	struct hd_struct *part;
+	struct block_device *part;
 };
 
 static void md_end_io(struct bio *bio)
@@ -8441,7 +8441,7 @@ static int is_mddev_idle(struct mddev *mddev, int init)
 	rcu_read_lock();
 	rdev_for_each_rcu(rdev, mddev) {
 		struct gendisk *disk = rdev->bdev->bd_disk;
-		curr_events = (int)part_stat_read_accum(disk->part0->bd_part, sectors) -
+		curr_events = (int)part_stat_read_accum(disk->part0, sectors) -
 			      atomic_read(&disk->sync_io);
 		/* sync IO will cause sync_io to increase before the disk_stats
 		 * as sync_io is counted when a request starts, and
diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index dca34489a1dc9e..8d90235e4fcc5a 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -89,12 +89,12 @@ static u16 nvmet_get_smart_log_nsid(struct nvmet_req *req,
 	if (!ns->bdev)
 		goto out;
 
-	host_reads = part_stat_read(ns->bdev->bd_part, ios[READ]);
-	data_units_read = DIV_ROUND_UP(part_stat_read(ns->bdev->bd_part,
-		sectors[READ]), 1000);
-	host_writes = part_stat_read(ns->bdev->bd_part, ios[WRITE]);
-	data_units_written = DIV_ROUND_UP(part_stat_read(ns->bdev->bd_part,
-		sectors[WRITE]), 1000);
+	host_reads = part_stat_read(ns->bdev, ios[READ]);
+	data_units_read =
+		DIV_ROUND_UP(part_stat_read(ns->bdev, sectors[READ]), 1000);
+	host_writes = part_stat_read(ns->bdev, ios[WRITE]);
+	data_units_written =
+		DIV_ROUND_UP(part_stat_read(ns->bdev, sectors[WRITE]), 1000);
 
 	put_unaligned_le64(host_reads, &slog->host_reads[0]);
 	put_unaligned_le64(data_units_read, &slog->data_units_read[0]);
@@ -120,12 +120,12 @@ static u16 nvmet_get_smart_log_all(struct nvmet_req *req,
 		/* we don't have the right data for file backed ns */
 		if (!ns->bdev)
 			continue;
-		host_reads += part_stat_read(ns->bdev->bd_part, ios[READ]);
+		host_reads += part_stat_read(ns->bdev, ios[READ]);
 		data_units_read += DIV_ROUND_UP(
-			part_stat_read(ns->bdev->bd_part, sectors[READ]), 1000);
-		host_writes += part_stat_read(ns->bdev->bd_part, ios[WRITE]);
+			part_stat_read(ns->bdev, sectors[READ]), 1000);
+		host_writes += part_stat_read(ns->bdev, ios[WRITE]);
 		data_units_written += DIV_ROUND_UP(
-			part_stat_read(ns->bdev->bd_part, sectors[WRITE]), 1000);
+			part_stat_read(ns->bdev, sectors[WRITE]), 1000);
 	}
 
 	put_unaligned_le64(host_reads, &slog->host_reads[0]);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 6633b20224d509..c303a0ff0b1701 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4048,9 +4048,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	sbi->s_sb = sb;
 	sbi->s_inode_readahead_blks = EXT4_DEF_INODE_READAHEAD_BLKS;
 	sbi->s_sb_block = sb_block;
-	if (sb->s_bdev->bd_part)
-		sbi->s_sectors_written_start =
-			part_stat_read(sb->s_bdev->bd_part, sectors[STAT_WRITE]);
+	sbi->s_sectors_written_start =
+		part_stat_read(sb->s_bdev, sectors[STAT_WRITE]);
 
 	/* Cleanup superblock name */
 	strreplace(sb->s_id, '/', '!');
@@ -5509,15 +5508,10 @@ static int ext4_commit_super(struct super_block *sb, int sync)
 	 */
 	if (!(sb->s_flags & SB_RDONLY))
 		ext4_update_tstamp(es, s_wtime);
-	if (sb->s_bdev->bd_part)
-		es->s_kbytes_written =
-			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written +
-			    ((part_stat_read(sb->s_bdev->bd_part,
-					     sectors[STAT_WRITE]) -
-			      EXT4_SB(sb)->s_sectors_written_start) >> 1));
-	else
-		es->s_kbytes_written =
-			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written);
+	es->s_kbytes_written =
+		cpu_to_le64(EXT4_SB(sb)->s_kbytes_written +
+		    ((part_stat_read(sb->s_bdev, sectors[STAT_WRITE]) -
+		      EXT4_SB(sb)->s_sectors_written_start) >> 1));
 	if (percpu_counter_initialized(&EXT4_SB(sb)->s_freeclusters_counter))
 		ext4_free_blocks_count_set(es,
 			EXT4_C2B(EXT4_SB(sb), percpu_counter_sum_positive(
diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c
index 4e27fe6ed3ae6a..075aa3a19ff5f1 100644
--- a/fs/ext4/sysfs.c
+++ b/fs/ext4/sysfs.c
@@ -62,11 +62,8 @@ static ssize_t session_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
 {
 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
 
-	if (!sb->s_bdev->bd_part)
-		return snprintf(buf, PAGE_SIZE, "0\n");
 	return snprintf(buf, PAGE_SIZE, "%lu\n",
-			(part_stat_read(sb->s_bdev->bd_part,
-					sectors[STAT_WRITE]) -
+			(part_stat_read(sb->s_bdev, sectors[STAT_WRITE]) -
 			 sbi->s_sectors_written_start) >> 1);
 }
 
@@ -74,12 +71,9 @@ static ssize_t lifetime_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
 {
 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
 
-	if (!sb->s_bdev->bd_part)
-		return snprintf(buf, PAGE_SIZE, "0\n");
 	return snprintf(buf, PAGE_SIZE, "%llu\n",
 			(unsigned long long)(sbi->s_kbytes_written +
-			((part_stat_read(sb->s_bdev->bd_part,
-					 sectors[STAT_WRITE]) -
+			((part_stat_read(sb->s_bdev, sectors[STAT_WRITE]) -
 			  EXT4_SB(sb)->s_sectors_written_start) >> 1)));
 }
 
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index cb700d79729680..49681a8d2b14a5 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1675,7 +1675,7 @@ static inline bool f2fs_is_multi_device(struct f2fs_sb_info *sbi)
  * and the return value is in kbytes. s is of struct f2fs_sb_info.
  */
 #define BD_PART_WRITTEN(s)						 \
-(((u64)part_stat_read((s)->sb->s_bdev->bd_part, sectors[STAT_WRITE]) -   \
+	(((u64)part_stat_read((s)->sb->s_bdev, sectors[STAT_WRITE]) -   \
 		(s)->sectors_written_start) >> 1)
 
 static inline void f2fs_update_time(struct f2fs_sb_info *sbi, int type)
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index d4e7fab352bacb..af9f449da64bac 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -3700,10 +3700,8 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 	}
 
 	/* For write statistics */
-	if (sb->s_bdev->bd_part)
-		sbi->sectors_written_start =
-			(u64)part_stat_read(sb->s_bdev->bd_part,
-					    sectors[STAT_WRITE]);
+	sbi->sectors_written_start =
+		(u64)part_stat_read(sb->s_bdev, sectors[STAT_WRITE]);
 
 	/* Read accumulated write IO statistics if exists */
 	seg_i = CURSEG_I(sbi, CURSEG_HOT_NODE);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 8fc0b266610f7f..0e83989b9678c3 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -191,7 +191,7 @@ struct request {
 	};
 
 	struct gendisk *rq_disk;
-	struct hd_struct *part;
+	struct block_device *part;
 #ifdef CONFIG_BLK_RQ_ALLOC_TIME
 	/* Time that the first bio started allocating this request. */
 	u64 alloc_time_ns;
@@ -1943,9 +1943,9 @@ unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors,
 void disk_end_io_acct(struct gendisk *disk, unsigned int op,
 		unsigned long start_time);
 
-unsigned long part_start_io_acct(struct gendisk *disk, struct hd_struct **part,
-				 struct bio *bio);
-void part_end_io_acct(struct hd_struct *part, struct bio *bio,
+unsigned long part_start_io_acct(struct gendisk *disk,
+		struct block_device **part, struct bio *bio);
+void part_end_io_acct(struct block_device *part, struct bio *bio,
 		      unsigned long start_time);
 
 /**
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 6e16c264439bdb..77443a1031e373 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -131,8 +131,8 @@ enum {
 struct disk_part_tbl {
 	struct rcu_head rcu_head;
 	int len;
-	struct hd_struct __rcu *last_lookup;
-	struct hd_struct __rcu *part[];
+	struct block_device __rcu *last_lookup;
+	struct block_device __rcu *part[];
 };
 
 struct disk_events;
diff --git a/include/linux/part_stat.h b/include/linux/part_stat.h
index 680de036691ef9..d2558121d48c00 100644
--- a/include/linux/part_stat.h
+++ b/include/linux/part_stat.h
@@ -25,26 +25,26 @@ struct disk_stats {
 #define part_stat_unlock()	preempt_enable()
 
 #define part_stat_get_cpu(part, field, cpu)				\
-	(per_cpu_ptr((part)->bdev->bd_stats, (cpu))->field)
+	(per_cpu_ptr((part)->bd_stats, (cpu))->field)
 
 #define part_stat_get(part, field)					\
 	part_stat_get_cpu(part, field, smp_processor_id())
 
 #define part_stat_read(part, field)					\
 ({									\
-	typeof((part)->bdev->bd_stats->field) res = 0;			\
+	typeof((part)->bd_stats->field) res = 0;			\
 	unsigned int _cpu;						\
 	for_each_possible_cpu(_cpu)					\
-		res += per_cpu_ptr((part)->bdev->bd_stats, _cpu)->field; \
+		res += per_cpu_ptr((part)->bd_stats, _cpu)->field; \
 	res;								\
 })
 
-static inline void part_stat_set_all(struct hd_struct *part, int value)
+static inline void part_stat_set_all(struct block_device *part, int value)
 {
 	int i;
 
 	for_each_possible_cpu(i)
-		memset(per_cpu_ptr(part->bdev->bd_stats, i), value,
+		memset(per_cpu_ptr(part->bd_stats, i), value,
 				sizeof(struct disk_stats));
 }
 
@@ -54,13 +54,12 @@ static inline void part_stat_set_all(struct hd_struct *part, int value)
 	 part_stat_read(part, field[STAT_DISCARD]))
 
 #define __part_stat_add(part, field, addnd)				\
-	__this_cpu_add((part)->bdev->bd_stats->field, addnd)
+	__this_cpu_add((part)->bd_stats->field, addnd)
 
 #define part_stat_add(part, field, addnd)	do {			\
 	__part_stat_add((part), field, addnd);				\
-	if ((part)->partno)						\
-		__part_stat_add(part_to_disk((part))->part0->bd_part,	\
-			field, addnd); \
+	if ((part)->bd_partno)						\
+		__part_stat_add(bdev_whole(part), field, addnd);	\
 } while (0)
 
 #define part_stat_dec(part, field)					\
-- 
2.29.2

--
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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 39/45] block: remove the partno field from struct hd_struct
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (37 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 38/45] block: switch partition lookup to use struct block_device Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 13:27 ` [dm-devel] [PATCH 40/45] block: pass a block_device to blk_alloc_devt Christoph Hellwig
                   ` (5 subsequent siblings)
  44 siblings, 0 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Just use the bd_partno field in struct block_device everywhere.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c           | 12 ++++++------
 block/partitions/core.c |  9 ++++-----
 include/linux/genhd.h   |  1 -
 init/do_mounts.c        |  2 +-
 4 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 197120c0c60f23..60004bc8ba5b56 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -576,8 +576,8 @@ int blk_alloc_devt(struct hd_struct *part, dev_t *devt)
 	int idx;
 
 	/* in consecutive minor range? */
-	if (part->partno < disk->minors) {
-		*devt = MKDEV(disk->major, disk->first_minor + part->partno);
+	if (part->bdev->bd_partno < disk->minors) {
+		*devt = MKDEV(disk->major, disk->first_minor + part->bdev->bd_partno);
 		return 0;
 	}
 
@@ -847,7 +847,7 @@ void del_gendisk(struct gendisk *disk)
 	disk_part_iter_init(&piter, disk,
 			     DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
 	while ((part = disk_part_iter_next(&piter))) {
-		invalidate_partition(disk, part->partno);
+		invalidate_partition(disk, part->bdev->bd_partno);
 		delete_partition(part);
 	}
 	disk_part_iter_exit(&piter);
@@ -989,7 +989,7 @@ void __init printk_all_partitions(void)
 			printk("%s%s %10llu %s %s", is_part0 ? "" : "  ",
 			       bdevt_str(part_devt(part), devt_buf),
 			       bdev_nr_sectors(part->bdev) >> 1,
-			       disk_name(disk, part->partno, name_buf),
+			       disk_name(disk, part->bdev->bd_partno, name_buf),
 			       part->bdev->bd_meta_info ?
 					part->bdev->bd_meta_info->uuid : "");
 			if (is_part0) {
@@ -1083,7 +1083,7 @@ static int show_partition(struct seq_file *seqf, void *v)
 		seq_printf(seqf, "%4d  %7d %10llu %s\n",
 			   MAJOR(part_devt(part)), MINOR(part_devt(part)),
 			   bdev_nr_sectors(part->bdev) >> 1,
-			   disk_name(sgp, part->partno, buf));
+			   disk_name(sgp, part->bdev->bd_partno, buf));
 	disk_part_iter_exit(&piter);
 
 	return 0;
@@ -1506,7 +1506,7 @@ static int diskstats_show(struct seq_file *seqf, void *v)
 			   "%lu %u"
 			   "\n",
 			   MAJOR(part_devt(hd)), MINOR(part_devt(hd)),
-			   disk_name(gp, hd->partno, buf),
+			   disk_name(gp, hd->bdev->bd_partno, buf),
 			   stat.ios[STAT_READ],
 			   stat.merges[STAT_READ],
 			   stat.sectors[STAT_READ],
diff --git a/block/partitions/core.c b/block/partitions/core.c
index 8beab9e7727e27..ee4f4e3237aa2d 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -184,7 +184,7 @@ static ssize_t part_partition_show(struct device *dev,
 {
 	struct hd_struct *p = dev_to_part(dev);
 
-	return sprintf(buf, "%d\n", p->partno);
+	return sprintf(buf, "%d\n", p->bdev->bd_partno);
 }
 
 static ssize_t part_start_show(struct device *dev,
@@ -274,7 +274,7 @@ static int part_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct hd_struct *part = dev_to_part(dev);
 
-	add_uevent_var(env, "PARTN=%u", part->partno);
+	add_uevent_var(env, "PARTN=%u", part->bdev->bd_partno);
 	if (part->bdev->bd_meta_info && part->bdev->bd_meta_info->volname[0])
 		add_uevent_var(env, "PARTNAME=%s",
 			       part->bdev->bd_meta_info->volname);
@@ -298,7 +298,7 @@ void delete_partition(struct hd_struct *part)
 	struct disk_part_tbl *ptbl =
 		rcu_dereference_protected(disk->part_tbl, 1);
 
-	rcu_assign_pointer(ptbl->part[part->partno], NULL);
+	rcu_assign_pointer(ptbl->part[part->bdev->bd_partno], NULL);
 	rcu_assign_pointer(ptbl->last_lookup, NULL);
 
 	kobject_put(part->bdev->bd_holder_dir);
@@ -372,7 +372,6 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 
 	bdev->bd_start_sect = start;
 	bdev_set_nr_sectors(bdev, len);
-	p->partno = partno;
 	bdev->bd_read_only = get_disk_ro(disk);
 
 	if (info) {
@@ -445,7 +444,7 @@ static bool partition_overlaps(struct gendisk *disk, sector_t start,
 
 	disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
 	while ((part = disk_part_iter_next(&piter))) {
-		if (part->partno == skip_partno ||
+		if (part->bdev->bd_partno == skip_partno ||
 		    start >= part->bdev->bd_start_sect +
 			bdev_nr_sectors(part->bdev) ||
 		    start + length <= part->bdev->bd_start_sect)
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 77443a1031e373..afe27a0b8f5dd8 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -54,7 +54,6 @@ struct partition_meta_info {
 struct hd_struct {
 	struct block_device *bdev;
 	struct device __dev;
-	int partno;
 };
 
 /**
diff --git a/init/do_mounts.c b/init/do_mounts.c
index 368ccb71850126..86bef93e72ebd6 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -136,7 +136,7 @@ static dev_t devt_from_partuuid(const char *uuid_str)
 		struct hd_struct *part;
 
 		part = disk_get_part(dev_to_disk(dev),
-				     dev_to_part(dev)->partno + offset);
+				     dev_to_part(dev)->bdev->bd_partno + offset);
 		if (part) {
 			devt = part_devt(part);
 			put_device(part_to_dev(part));
-- 
2.29.2

--
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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 40/45] block: pass a block_device to blk_alloc_devt
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (38 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 39/45] block: remove the partno field from struct hd_struct Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 13:27 ` [dm-devel] [PATCH 41/45] block: pass a block_device to invalidate_partition Christoph Hellwig
                   ` (4 subsequent siblings)
  44 siblings, 0 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Pass the block_device actually needed instead of the hd_struct.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk.h             |  2 +-
 block/genhd.c           | 14 +++++++-------
 block/partitions/core.c |  2 +-
 3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/block/blk.h b/block/blk.h
index d5bf8f3a078186..9657c6da7c770c 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -350,7 +350,7 @@ static inline void blk_queue_free_zone_bitmaps(struct request_queue *q) {}
 
 struct block_device *disk_map_sector_rcu(struct gendisk *disk, sector_t sector);
 
-int blk_alloc_devt(struct hd_struct *part, dev_t *devt);
+int blk_alloc_devt(struct block_device *part, dev_t *devt);
 void blk_free_devt(dev_t devt);
 char *disk_name(struct gendisk *hd, int partno, char *buf);
 #define ADDPART_FLAG_NONE	0
diff --git a/block/genhd.c b/block/genhd.c
index 60004bc8ba5b56..498c816e90df64 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -557,8 +557,8 @@ static int blk_mangle_minor(int minor)
 }
 
 /**
- * blk_alloc_devt - allocate a dev_t for a partition
- * @part: partition to allocate dev_t for
+ * blk_alloc_devt - allocate a dev_t for a block device
+ * @bdev: block device to allocate dev_t for
  * @devt: out parameter for resulting dev_t
  *
  * Allocate a dev_t for block device.
@@ -570,14 +570,14 @@ static int blk_mangle_minor(int minor)
  * CONTEXT:
  * Might sleep.
  */
-int blk_alloc_devt(struct hd_struct *part, dev_t *devt)
+int blk_alloc_devt(struct block_device *bdev, dev_t *devt)
 {
-	struct gendisk *disk = part_to_disk(part);
+	struct gendisk *disk = bdev->bd_disk;
 	int idx;
 
 	/* in consecutive minor range? */
-	if (part->bdev->bd_partno < disk->minors) {
-		*devt = MKDEV(disk->major, disk->first_minor + part->bdev->bd_partno);
+	if (bdev->bd_partno < disk->minors) {
+		*devt = MKDEV(disk->major, disk->first_minor + bdev->bd_partno);
 		return 0;
 	}
 
@@ -733,7 +733,7 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
 
 	disk->flags |= GENHD_FL_UP;
 
-	retval = blk_alloc_devt(disk->part0->bd_part, &devt);
+	retval = blk_alloc_devt(disk->part0, &devt);
 	if (retval) {
 		WARN_ON(1);
 		return;
diff --git a/block/partitions/core.c b/block/partitions/core.c
index ee4f4e3237aa2d..45fed1108d4425 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -392,7 +392,7 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 	pdev->type = &part_type;
 	pdev->parent = ddev;
 
-	err = blk_alloc_devt(p, &devt);
+	err = blk_alloc_devt(bdev, &devt);
 	if (err)
 		goto out_bdput;
 	pdev->devt = devt;
-- 
2.29.2

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 41/45] block: pass a block_device to invalidate_partition
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (39 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 40/45] block: pass a block_device to blk_alloc_devt Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 13:27 ` [dm-devel] [PATCH 42/45] block: switch disk_part_iter_* to use a struct block_device Christoph Hellwig
                   ` (3 subsequent siblings)
  44 siblings, 0 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Pass the block_device actually needed instead of looking it up using
bdget_disk.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 498c816e90df64..2985740eab084b 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -790,14 +790,8 @@ void device_add_disk_no_queue_reg(struct device *parent, struct gendisk *disk)
 }
 EXPORT_SYMBOL(device_add_disk_no_queue_reg);
 
-static void invalidate_partition(struct gendisk *disk, int partno)
+static void invalidate_partition(struct block_device *bdev)
 {
-	struct block_device *bdev;
-
-	bdev = bdget_disk(disk, partno);
-	if (!bdev)
-		return;
-
 	fsync_bdev(bdev);
 	__invalidate_device(bdev, true);
 
@@ -806,7 +800,6 @@ static void invalidate_partition(struct gendisk *disk, int partno)
 	 * as last inode reference is dropped.
 	 */
 	remove_inode_hash(bdev->bd_inode);
-	bdput(bdev);
 }
 
 /**
@@ -847,12 +840,12 @@ void del_gendisk(struct gendisk *disk)
 	disk_part_iter_init(&piter, disk,
 			     DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
 	while ((part = disk_part_iter_next(&piter))) {
-		invalidate_partition(disk, part->bdev->bd_partno);
+		invalidate_partition(part->bdev);
 		delete_partition(part);
 	}
 	disk_part_iter_exit(&piter);
 
-	invalidate_partition(disk, 0);
+	invalidate_partition(disk->part0);
 	set_capacity(disk, 0);
 
 	if (!(disk->flags & GENHD_FL_HIDDEN)) {
-- 
2.29.2

--
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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 42/45] block: switch disk_part_iter_* to use a struct block_device
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (40 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 41/45] block: pass a block_device to invalidate_partition Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 13:27 ` [dm-devel] [PATCH 43/45] f2fs: remove a few bd_part checks Christoph Hellwig
                   ` (2 subsequent siblings)
  44 siblings, 0 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Switch the partition iter infrastructure to iterate over block_device
references instead of hd_struct ones mostly used to get at the
block_device.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c             | 57 +++++++++++++++++++--------------------
 block/partitions/core.c   | 13 +++++----
 drivers/s390/block/dasd.c |  8 +++---
 include/linux/genhd.h     |  4 +--
 4 files changed, 40 insertions(+), 42 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 2985740eab084b..f0bf10192066ac 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -231,7 +231,7 @@ EXPORT_SYMBOL_GPL(disk_part_iter_init);
  * CONTEXT:
  * Don't care.
  */
-struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter)
+struct block_device *disk_part_iter_next(struct disk_part_iter *piter)
 {
 	struct disk_part_tbl *ptbl;
 	int inc, end;
@@ -269,8 +269,7 @@ struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter)
 		      piter->idx == 0))
 			continue;
 
-		get_device(part_to_dev(part->bd_part));
-		piter->part = part->bd_part;
+		piter->part = bdgrab(part);
 		piter->idx += inc;
 		break;
 	}
@@ -292,7 +291,8 @@ EXPORT_SYMBOL_GPL(disk_part_iter_next);
  */
 void disk_part_iter_exit(struct disk_part_iter *piter)
 {
-	disk_put_part(piter->part);
+	if (piter->part)
+		bdput(piter->part);
 	piter->part = NULL;
 }
 EXPORT_SYMBOL_GPL(disk_part_iter_exit);
@@ -333,7 +333,6 @@ struct block_device *disk_map_sector_rcu(struct gendisk *disk, sector_t sector)
 
 	for (i = 1; i < ptbl->len; i++) {
 		part = rcu_dereference(ptbl->part[i]);
-
 		if (part && sector_in_part(part, sector)) {
 			rcu_assign_pointer(ptbl->last_lookup, part);
 			goto out_unlock;
@@ -634,7 +633,7 @@ static void register_disk(struct device *parent, struct gendisk *disk,
 {
 	struct device *ddev = disk_to_dev(disk);
 	struct disk_part_iter piter;
-	struct hd_struct *part;
+	struct block_device *part;
 	int err;
 
 	ddev->parent = parent;
@@ -684,7 +683,7 @@ static void register_disk(struct device *parent, struct gendisk *disk,
 	/* announce possible partitions */
 	disk_part_iter_init(&piter, disk, 0);
 	while ((part = disk_part_iter_next(&piter)))
-		kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD);
+		kobject_uevent(bdev_kobj(part), KOBJ_ADD);
 	disk_part_iter_exit(&piter);
 
 	if (disk->queue->backing_dev_info->dev) {
@@ -824,7 +823,7 @@ static void invalidate_partition(struct block_device *bdev)
 void del_gendisk(struct gendisk *disk)
 {
 	struct disk_part_iter piter;
-	struct hd_struct *part;
+	struct block_device *part;
 
 	might_sleep();
 
@@ -840,8 +839,8 @@ void del_gendisk(struct gendisk *disk)
 	disk_part_iter_init(&piter, disk,
 			     DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
 	while ((part = disk_part_iter_next(&piter))) {
-		invalidate_partition(part->bdev);
-		delete_partition(part);
+		invalidate_partition(part);
+		delete_partition(part->bd_part);
 	}
 	disk_part_iter_exit(&piter);
 
@@ -958,7 +957,7 @@ void __init printk_all_partitions(void)
 	while ((dev = class_dev_iter_next(&iter))) {
 		struct gendisk *disk = dev_to_disk(dev);
 		struct disk_part_iter piter;
-		struct hd_struct *part;
+		struct block_device *part;
 		char name_buf[BDEVNAME_SIZE];
 		char devt_buf[BDEVT_SIZE];
 
@@ -977,14 +976,14 @@ void __init printk_all_partitions(void)
 		 */
 		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
 		while ((part = disk_part_iter_next(&piter))) {
-			bool is_part0 = part == disk->part0->bd_part;
+			bool is_part0 = part == disk->part0;
 
 			printk("%s%s %10llu %s %s", is_part0 ? "" : "  ",
-			       bdevt_str(part_devt(part), devt_buf),
-			       bdev_nr_sectors(part->bdev) >> 1,
-			       disk_name(disk, part->bdev->bd_partno, name_buf),
-			       part->bdev->bd_meta_info ?
-					part->bdev->bd_meta_info->uuid : "");
+			       bdevt_str(part->bd_dev, devt_buf),
+			       bdev_nr_sectors(part) >> 1,
+			       disk_name(disk, part->bd_partno, name_buf),
+			       part->bd_meta_info ?
+					part->bd_meta_info->uuid : "");
 			if (is_part0) {
 				if (dev->parent && dev->parent->driver)
 					printk(" driver: %s\n",
@@ -1060,7 +1059,7 @@ static int show_partition(struct seq_file *seqf, void *v)
 {
 	struct gendisk *sgp = v;
 	struct disk_part_iter piter;
-	struct hd_struct *part;
+	struct block_device *part;
 	char buf[BDEVNAME_SIZE];
 
 	/* Don't show non-partitionable removeable devices or empty devices */
@@ -1074,9 +1073,9 @@ static int show_partition(struct seq_file *seqf, void *v)
 	disk_part_iter_init(&piter, sgp, DISK_PITER_INCL_PART0);
 	while ((part = disk_part_iter_next(&piter)))
 		seq_printf(seqf, "%4d  %7d %10llu %s\n",
-			   MAJOR(part_devt(part)), MINOR(part_devt(part)),
-			   bdev_nr_sectors(part->bdev) >> 1,
-			   disk_name(sgp, part->bdev->bd_partno, buf));
+			   MAJOR(part->bd_dev), MINOR(part->bd_dev),
+			   bdev_nr_sectors(part) >> 1,
+			   disk_name(sgp, part->bd_partno, buf));
 	disk_part_iter_exit(&piter);
 
 	return 0;
@@ -1470,7 +1469,7 @@ static int diskstats_show(struct seq_file *seqf, void *v)
 {
 	struct gendisk *gp = v;
 	struct disk_part_iter piter;
-	struct hd_struct *hd;
+	struct block_device *hd;
 	char buf[BDEVNAME_SIZE];
 	unsigned int inflight;
 	struct disk_stats stat;
@@ -1485,11 +1484,11 @@ static int diskstats_show(struct seq_file *seqf, void *v)
 
 	disk_part_iter_init(&piter, gp, DISK_PITER_INCL_EMPTY_PART0);
 	while ((hd = disk_part_iter_next(&piter))) {
-		part_stat_read_all(hd, &stat);
+		part_stat_read_all(hd->bd_part, &stat);
 		if (queue_is_mq(gp->queue))
-			inflight = blk_mq_in_flight(gp->queue, hd->bdev);
+			inflight = blk_mq_in_flight(gp->queue, hd);
 		else
-			inflight = part_in_flight(hd->bdev);
+			inflight = part_in_flight(hd);
 
 		seq_printf(seqf, "%4d %7d %s "
 			   "%lu %lu %lu %u "
@@ -1498,8 +1497,8 @@ static int diskstats_show(struct seq_file *seqf, void *v)
 			   "%lu %lu %lu %u "
 			   "%lu %u"
 			   "\n",
-			   MAJOR(part_devt(hd)), MINOR(part_devt(hd)),
-			   disk_name(gp, hd->bdev->bd_partno, buf),
+			   MAJOR(hd->bd_dev), MINOR(hd->bd_dev),
+			   disk_name(gp, hd->bd_partno, buf),
 			   stat.ios[STAT_READ],
 			   stat.merges[STAT_READ],
 			   stat.sectors[STAT_READ],
@@ -1654,7 +1653,7 @@ static void set_disk_ro_uevent(struct gendisk *gd, int ro)
 void set_disk_ro(struct gendisk *disk, int flag)
 {
 	struct disk_part_iter piter;
-	struct hd_struct *part;
+	struct block_device *part;
 
 	if (disk->part0->bd_read_only != flag) {
 		set_disk_ro_uevent(disk, flag);
@@ -1663,7 +1662,7 @@ void set_disk_ro(struct gendisk *disk, int flag)
 
 	disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
 	while ((part = disk_part_iter_next(&piter)))
-		part->bdev->bd_read_only = flag;
+		part->bd_read_only = flag;
 	disk_part_iter_exit(&piter);
 }
 
diff --git a/block/partitions/core.c b/block/partitions/core.c
index 45fed1108d4425..c189ebd4569812 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -439,15 +439,14 @@ static bool partition_overlaps(struct gendisk *disk, sector_t start,
 		sector_t length, int skip_partno)
 {
 	struct disk_part_iter piter;
-	struct hd_struct *part;
+	struct block_device *part;
 	bool overlap = false;
 
 	disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
 	while ((part = disk_part_iter_next(&piter))) {
-		if (part->bdev->bd_partno == skip_partno ||
-		    start >= part->bdev->bd_start_sect +
-			bdev_nr_sectors(part->bdev) ||
-		    start + length <= part->bdev->bd_start_sect)
+		if (part->bd_partno == skip_partno ||
+		    start >= part->bd_start_sect + bdev_nr_sectors(part) ||
+		    start + length <= part->bd_start_sect)
 			continue;
 		overlap = true;
 		break;
@@ -568,7 +567,7 @@ static bool disk_unlock_native_capacity(struct gendisk *disk)
 int blk_drop_partitions(struct block_device *bdev)
 {
 	struct disk_part_iter piter;
-	struct hd_struct *part;
+	struct block_device *part;
 
 	if (bdev->bd_part_count)
 		return -EBUSY;
@@ -578,7 +577,7 @@ int blk_drop_partitions(struct block_device *bdev)
 
 	disk_part_iter_init(&piter, bdev->bd_disk, DISK_PITER_INCL_EMPTY);
 	while ((part = disk_part_iter_next(&piter)))
-		delete_partition(part);
+		delete_partition(part->bd_part);
 	disk_part_iter_exit(&piter);
 
 	return 0;
diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index db24e04ee9781e..1825fa8d05a780 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -432,7 +432,7 @@ dasd_state_ready_to_online(struct dasd_device * device)
 {
 	struct gendisk *disk;
 	struct disk_part_iter piter;
-	struct hd_struct *part;
+	struct block_device *part;
 
 	device->state = DASD_STATE_ONLINE;
 	if (device->block) {
@@ -445,7 +445,7 @@ dasd_state_ready_to_online(struct dasd_device * device)
 		disk = device->block->bdev->bd_disk;
 		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
 		while ((part = disk_part_iter_next(&piter)))
-			kobject_uevent(&part_to_dev(part)->kobj, KOBJ_CHANGE);
+			kobject_uevent(bdev_kobj(part), KOBJ_CHANGE);
 		disk_part_iter_exit(&piter);
 	}
 	return 0;
@@ -459,7 +459,7 @@ static int dasd_state_online_to_ready(struct dasd_device *device)
 	int rc;
 	struct gendisk *disk;
 	struct disk_part_iter piter;
-	struct hd_struct *part;
+	struct block_device *part;
 
 	if (device->discipline->online_to_ready) {
 		rc = device->discipline->online_to_ready(device);
@@ -472,7 +472,7 @@ static int dasd_state_online_to_ready(struct dasd_device *device)
 		disk = device->block->bdev->bd_disk;
 		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
 		while ((part = disk_part_iter_next(&piter)))
-			kobject_uevent(&part_to_dev(part)->kobj, KOBJ_CHANGE);
+			kobject_uevent(bdev_kobj(part), KOBJ_CHANGE);
 		disk_part_iter_exit(&piter);
 	}
 	return 0;
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index afe27a0b8f5dd8..de2ee5ffeefe45 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -245,14 +245,14 @@ static inline void disk_put_part(struct hd_struct *part)
 
 struct disk_part_iter {
 	struct gendisk		*disk;
-	struct hd_struct	*part;
+	struct block_device	*part;
 	int			idx;
 	unsigned int		flags;
 };
 
 extern void disk_part_iter_init(struct disk_part_iter *piter,
 				 struct gendisk *disk, unsigned int flags);
-extern struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter);
+struct block_device *disk_part_iter_next(struct disk_part_iter *piter);
 extern void disk_part_iter_exit(struct disk_part_iter *piter);
 extern bool disk_has_partitions(struct gendisk *disk);
 
-- 
2.29.2

--
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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 43/45] f2fs: remove a few bd_part checks
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (41 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 42/45] block: switch disk_part_iter_* to use a struct block_device Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-25  6:12   ` Chao Yu
  2020-11-24 13:27 ` [dm-devel] [PATCH 44/45] block: merge struct block_device and struct hd_struct Christoph Hellwig
  2020-11-24 13:27 ` [dm-devel] [PATCH 45/45] block: stop using bdget_disk for partition 0 Christoph Hellwig
  44 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

bd_part is never NULL for a block device in use by a file system, so
remove the checks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/f2fs/checkpoint.c | 5 +----
 fs/f2fs/sysfs.c      | 9 ---------
 2 files changed, 1 insertion(+), 13 deletions(-)

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 023462e80e58d5..54a1905af052cc 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1395,7 +1395,6 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 	__u32 crc32 = 0;
 	int i;
 	int cp_payload_blks = __cp_payload(sbi);
-	struct super_block *sb = sbi->sb;
 	struct curseg_info *seg_i = CURSEG_I(sbi, CURSEG_HOT_NODE);
 	u64 kbytes_written;
 	int err;
@@ -1489,9 +1488,7 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 	start_blk += data_sum_blocks;
 
 	/* Record write statistics in the hot node summary */
-	kbytes_written = sbi->kbytes_written;
-	if (sb->s_bdev->bd_part)
-		kbytes_written += BD_PART_WRITTEN(sbi);
+	kbytes_written = sbi->kbytes_written + BD_PART_WRITTEN(sbi);
 
 	seg_i->journal->info.kbytes_written = cpu_to_le64(kbytes_written);
 
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index ec77ccfea923dc..24e876e849c512 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -90,11 +90,6 @@ static ssize_t free_segments_show(struct f2fs_attr *a,
 static ssize_t lifetime_write_kbytes_show(struct f2fs_attr *a,
 		struct f2fs_sb_info *sbi, char *buf)
 {
-	struct super_block *sb = sbi->sb;
-
-	if (!sb->s_bdev->bd_part)
-		return sprintf(buf, "0\n");
-
 	return sprintf(buf, "%llu\n",
 			(unsigned long long)(sbi->kbytes_written +
 			BD_PART_WRITTEN(sbi)));
@@ -103,12 +98,8 @@ static ssize_t lifetime_write_kbytes_show(struct f2fs_attr *a,
 static ssize_t features_show(struct f2fs_attr *a,
 		struct f2fs_sb_info *sbi, char *buf)
 {
-	struct super_block *sb = sbi->sb;
 	int len = 0;
 
-	if (!sb->s_bdev->bd_part)
-		return sprintf(buf, "0\n");
-
 	if (f2fs_sb_has_encrypt(sbi))
 		len += scnprintf(buf, PAGE_SIZE - len, "%s",
 						"encryption");
-- 
2.29.2

--
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https://www.redhat.com/mailman/listinfo/dm-devel


^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 44/45] block: merge struct block_device and struct hd_struct
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (42 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 43/45] f2fs: remove a few bd_part checks Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  2020-11-24 13:27 ` [dm-devel] [PATCH 45/45] block: stop using bdget_disk for partition 0 Christoph Hellwig
  44 siblings, 0 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

Instead of having two structures that represent each block device with
different life time rules, merge them into a single one.  This also
greatly simplifies the reference counting rules, as we can use the inode
reference count as the main reference count for the new struct
block_device, with the device model reference front ending it for device
model interaction.  The percpu refcount in struct hd_struct is entirely
gone given that struct block_device must be opened and thus valid for
the duration of the I/O.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-cgroup.c        |   9 ++-
 block/blk.h               |   2 +-
 block/genhd.c             |  86 +++++++++-------------------
 block/partitions/core.c   | 116 +++++++++++++++-----------------------
 fs/block_dev.c            |   9 ---
 include/linux/blk_types.h |   8 ++-
 include/linux/blkdev.h    |   1 -
 include/linux/genhd.h     |  40 +++----------
 init/do_mounts.c          |  21 ++++---
 kernel/trace/blktrace.c   |  43 +++-----------
 10 files changed, 109 insertions(+), 226 deletions(-)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index a598f86e014137..99e0e0b3e347de 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -820,9 +820,9 @@ static void blkcg_fill_root_iostats(void)
 
 	class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
 	while ((dev = class_dev_iter_next(&iter))) {
-		struct gendisk *disk = dev_to_disk(dev);
-		struct hd_struct *part = disk_get_part(disk, 0);
-		struct blkcg_gq *blkg = blk_queue_root_blkg(disk->queue);
+		struct block_device *bdev = dev_to_bdev(dev);
+		struct blkcg_gq *blkg =
+			blk_queue_root_blkg(bdev->bd_disk->queue);
 		struct blkg_iostat tmp;
 		int cpu;
 
@@ -830,7 +830,7 @@ static void blkcg_fill_root_iostats(void)
 		for_each_possible_cpu(cpu) {
 			struct disk_stats *cpu_dkstats;
 
-			cpu_dkstats = per_cpu_ptr(part->bdev->bd_stats, cpu);
+			cpu_dkstats = per_cpu_ptr(bdev->bd_stats, cpu);
 			tmp.ios[BLKG_IOSTAT_READ] +=
 				cpu_dkstats->ios[STAT_READ];
 			tmp.ios[BLKG_IOSTAT_WRITE] +=
@@ -849,7 +849,6 @@ static void blkcg_fill_root_iostats(void)
 			blkg_iostat_set(&blkg->iostat.cur, &tmp);
 			u64_stats_update_end(&blkg->iostat.sync);
 		}
-		disk_put_part(part);
 	}
 }
 
diff --git a/block/blk.h b/block/blk.h
index 9657c6da7c770c..98f0b1ae264120 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -356,7 +356,7 @@ char *disk_name(struct gendisk *hd, int partno, char *buf);
 #define ADDPART_FLAG_NONE	0
 #define ADDPART_FLAG_RAID	1
 #define ADDPART_FLAG_WHOLEDISK	2
-void delete_partition(struct hd_struct *part);
+void delete_partition(struct block_device *part);
 int bdev_add_partition(struct block_device *bdev, int partno,
 		sector_t start, sector_t length);
 int bdev_del_partition(struct block_device *bdev, int partno);
diff --git a/block/genhd.c b/block/genhd.c
index f0bf10192066ac..e1f67b9951f0ec 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -96,13 +96,14 @@ const char *bdevname(struct block_device *bdev, char *buf)
 }
 EXPORT_SYMBOL(bdevname);
 
-static void part_stat_read_all(struct hd_struct *part, struct disk_stats *stat)
+static void part_stat_read_all(struct block_device *part,
+		struct disk_stats *stat)
 {
 	int cpu;
 
 	memset(stat, 0, sizeof(struct disk_stats));
 	for_each_possible_cpu(cpu) {
-		struct disk_stats *ptr = per_cpu_ptr(part->bdev->bd_stats, cpu);
+		struct disk_stats *ptr = per_cpu_ptr(part->bd_stats, cpu);
 		int group;
 
 		for (group = 0; group < NR_STAT_GROUPS; group++) {
@@ -157,36 +158,6 @@ struct block_device *__disk_get_part(struct gendisk *disk, int partno)
 	return rcu_dereference(ptbl->part[partno]);
 }
 
-/**
- * disk_get_part - get partition
- * @disk: disk to look partition from
- * @partno: partition number
- *
- * Look for partition @partno from @disk.  If found, increment
- * reference count and return it.
- *
- * CONTEXT:
- * Don't care.
- *
- * RETURNS:
- * Pointer to the found partition on success, NULL if not found.
- */
-struct hd_struct *disk_get_part(struct gendisk *disk, int partno)
-{
-	struct block_device *part;
-
-	rcu_read_lock();
-	part = __disk_get_part(disk, partno);
-	if (!part) {
-		rcu_read_unlock();
-		return NULL;
-	}
-
-	get_device(part_to_dev(part->bd_part));
-	rcu_read_unlock();
-	return part->bd_part;
-}
-
 /**
  * disk_part_iter_init - initialize partition iterator
  * @piter: iterator to initialize
@@ -840,7 +811,7 @@ void del_gendisk(struct gendisk *disk)
 			     DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
 	while ((part = disk_part_iter_next(&piter))) {
 		invalidate_partition(part);
-		delete_partition(part->bd_part);
+		delete_partition(part);
 	}
 	disk_part_iter_exit(&piter);
 
@@ -931,13 +902,13 @@ void blk_request_module(dev_t devt)
  */
 struct block_device *bdget_disk(struct gendisk *disk, int partno)
 {
-	struct hd_struct *part;
 	struct block_device *bdev = NULL;
 
-	part = disk_get_part(disk, partno);
-	if (part)
-		bdev = bdget_part(part);
-	disk_put_part(part);
+	rcu_read_lock();
+	bdev = __disk_get_part(disk, partno);
+	if (bdev)
+		bdgrab(bdev);
+	rcu_read_unlock();
 
 	return bdev;
 }
@@ -1154,24 +1125,22 @@ static ssize_t disk_ro_show(struct device *dev,
 ssize_t part_size_show(struct device *dev,
 		       struct device_attribute *attr, char *buf)
 {
-	struct hd_struct *p = dev_to_part(dev);
-
-	return sprintf(buf, "%llu\n", bdev_nr_sectors(p->bdev));
+	return sprintf(buf, "%llu\n", bdev_nr_sectors(dev_to_bdev(dev)));
 }
 
 ssize_t part_stat_show(struct device *dev,
 		       struct device_attribute *attr, char *buf)
 {
-	struct hd_struct *p = dev_to_part(dev);
-	struct request_queue *q = part_to_disk(p)->queue;
+	struct block_device *bdev = dev_to_bdev(dev);
+	struct request_queue *q = bdev->bd_disk->queue;
 	struct disk_stats stat;
 	unsigned int inflight;
 
-	part_stat_read_all(p, &stat);
+	part_stat_read_all(bdev, &stat);
 	if (queue_is_mq(q))
-		inflight = blk_mq_in_flight(q, p->bdev);
+		inflight = blk_mq_in_flight(q, bdev);
 	else
-		inflight = part_in_flight(p->bdev);
+		inflight = part_in_flight(bdev);
 
 	return sprintf(buf,
 		"%8lu %8lu %8llu %8u "
@@ -1206,14 +1175,14 @@ ssize_t part_stat_show(struct device *dev,
 ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr,
 			   char *buf)
 {
-	struct hd_struct *p = dev_to_part(dev);
-	struct request_queue *q = part_to_disk(p)->queue;
+	struct block_device *bdev = dev_to_bdev(dev);
+	struct request_queue *q = bdev->bd_disk->queue;
 	unsigned int inflight[2];
 
 	if (queue_is_mq(q))
-		blk_mq_in_flight_rw(q, p->bdev, inflight);
+		blk_mq_in_flight_rw(q, bdev, inflight);
 	else
-		part_in_flight_rw(p->bdev, inflight);
+		part_in_flight_rw(bdev, inflight);
 
 	return sprintf(buf, "%8u %8u\n", inflight[0], inflight[1]);
 }
@@ -1261,16 +1230,14 @@ static DEVICE_ATTR(badblocks, 0644, disk_badblocks_show, disk_badblocks_store);
 ssize_t part_fail_show(struct device *dev,
 		       struct device_attribute *attr, char *buf)
 {
-	struct hd_struct *p = dev_to_part(dev);
-
-	return sprintf(buf, "%d\n", p->bdev->bd_make_it_fail);
+	return sprintf(buf, "%d\n", dev_to_bdev(dev)->make_it_fail);
 }
 
 ssize_t part_fail_store(struct device *dev,
 			struct device_attribute *attr,
 			const char *buf, size_t count)
 {
-	struct hd_struct *p = dev_to_part(dev);
+	struct block_device *p = dev_to_bdev(dev);
 	int i;
 
 	if (count > 0 && sscanf(buf, "%d", &i) > 0)
@@ -1484,7 +1451,7 @@ static int diskstats_show(struct seq_file *seqf, void *v)
 
 	disk_part_iter_init(&piter, gp, DISK_PITER_INCL_EMPTY_PART0);
 	while ((hd = disk_part_iter_next(&piter))) {
-		part_stat_read_all(hd->bd_part, &stat);
+		part_stat_read_all(hd, &stat);
 		if (queue_is_mq(gp->queue))
 			inflight = blk_mq_in_flight(gp->queue, hd);
 		else
@@ -1556,7 +1523,7 @@ dev_t blk_lookup_devt(const char *name, int partno)
 	class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
 	while ((dev = class_dev_iter_next(&iter))) {
 		struct gendisk *disk = dev_to_disk(dev);
-		struct hd_struct *part;
+		struct block_device *part;
 
 		if (strcmp(dev_name(dev), name))
 			continue;
@@ -1569,13 +1536,12 @@ dev_t blk_lookup_devt(const char *name, int partno)
 				     MINOR(dev->devt) + partno);
 			break;
 		}
-		part = disk_get_part(disk, partno);
+		part = bdget_disk(disk, partno);
 		if (part) {
-			devt = part_devt(part);
-			disk_put_part(part);
+			devt = part->bd_dev;
+			bdput(part);
 			break;
 		}
-		disk_put_part(part);
 	}
 	class_dev_iter_exit(&iter);
 	return devt;
diff --git a/block/partitions/core.c b/block/partitions/core.c
index c189ebd4569812..8d774840b14047 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -182,44 +182,39 @@ static struct parsed_partitions *check_partition(struct gendisk *hd,
 static ssize_t part_partition_show(struct device *dev,
 				   struct device_attribute *attr, char *buf)
 {
-	struct hd_struct *p = dev_to_part(dev);
-
-	return sprintf(buf, "%d\n", p->bdev->bd_partno);
+	return sprintf(buf, "%d\n", dev_to_bdev(dev)->bd_partno);
 }
 
 static ssize_t part_start_show(struct device *dev,
 			       struct device_attribute *attr, char *buf)
 {
-	struct hd_struct *p = dev_to_part(dev);
-
-	return sprintf(buf, "%llu\n",(unsigned long long)p->bdev->bd_start_sect);
+	return sprintf(buf, "%llu\n", dev_to_bdev(dev)->bd_start_sect);
 }
 
 static ssize_t part_ro_show(struct device *dev,
 			    struct device_attribute *attr, char *buf)
 {
-	struct hd_struct *p = dev_to_part(dev);
-	return sprintf(buf, "%d\n", p->bdev->bd_read_only);
+	return sprintf(buf, "%d\n", dev_to_bdev(dev)->bd_read_only);
 }
 
 static ssize_t part_alignment_offset_show(struct device *dev,
 					  struct device_attribute *attr, char *buf)
 {
-	struct hd_struct *p = dev_to_part(dev);
+	struct block_device *bdev = dev_to_bdev(dev);
 
 	return sprintf(buf, "%u\n",
-		queue_limit_alignment_offset(&part_to_disk(p)->queue->limits,
-				p->bdev->bd_start_sect));
+		queue_limit_alignment_offset(&bdev->bd_disk->queue->limits,
+				bdev->bd_start_sect));
 }
 
 static ssize_t part_discard_alignment_show(struct device *dev,
 					   struct device_attribute *attr, char *buf)
 {
-	struct hd_struct *p = dev_to_part(dev);
+	struct block_device *bdev = dev_to_bdev(dev);
 
 	return sprintf(buf, "%u\n",
-		queue_limit_discard_alignment(&part_to_disk(p)->queue->limits,
-				p->bdev->bd_start_sect));
+		queue_limit_discard_alignment(&bdev->bd_disk->queue->limits,
+				bdev->bd_start_sect));
 }
 
 static DEVICE_ATTR(partition, 0444, part_partition_show, NULL);
@@ -264,20 +259,19 @@ static const struct attribute_group *part_attr_groups[] = {
 
 static void part_release(struct device *dev)
 {
-	struct hd_struct *p = dev_to_part(dev);
+	struct block_device *p = dev_to_bdev(dev);
 
 	blk_free_devt(dev->devt);
-	bdput(p->bdev);
+	bdput(p);
 }
 
 static int part_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
-	struct hd_struct *part = dev_to_part(dev);
+	struct block_device *part = dev_to_bdev(dev);
 
-	add_uevent_var(env, "PARTN=%u", part->bdev->bd_partno);
-	if (part->bdev->bd_meta_info && part->bdev->bd_meta_info->volname[0])
-		add_uevent_var(env, "PARTNAME=%s",
-			       part->bdev->bd_meta_info->volname);
+	add_uevent_var(env, "PARTN=%u", part->bd_partno);
+	if (part->bd_meta_info && part->bd_meta_info->volname[0])
+		add_uevent_var(env, "PARTNAME=%s", part->bd_meta_info->volname);
 	return 0;
 }
 
@@ -292,25 +286,25 @@ struct device_type part_type = {
  * Must be called either with bd_mutex held, before a disk can be opened or
  * after all disk users are gone.
  */
-void delete_partition(struct hd_struct *part)
+void delete_partition(struct block_device *part)
 {
-	struct gendisk *disk = part_to_disk(part);
+	struct gendisk *disk = part->bd_disk;
 	struct disk_part_tbl *ptbl =
 		rcu_dereference_protected(disk->part_tbl, 1);
 
-	rcu_assign_pointer(ptbl->part[part->bdev->bd_partno], NULL);
+	rcu_assign_pointer(ptbl->part[part->bd_partno], NULL);
 	rcu_assign_pointer(ptbl->last_lookup, NULL);
 
-	kobject_put(part->bdev->bd_holder_dir);
-	device_del(part_to_dev(part));
+	kobject_put(part->bd_holder_dir);
+	device_del(&part->bd_device);
 
 	/*
 	 * Remove the block device from the inode hash, so that it cannot be
 	 * looked up while waiting for the RCU grace period.
 	 */
-	remove_inode_hash(part->bdev->bd_inode);
+	remove_inode_hash(part->bd_inode);
 
-	put_device(part_to_dev(part));
+	put_device(&part->bd_device);
 }
 
 static ssize_t whole_disk_show(struct device *dev,
@@ -324,11 +318,10 @@ static DEVICE_ATTR(whole_disk, 0444, whole_disk_show, NULL);
  * Must be called either with bd_mutex held, before a disk can be opened or
  * after all disk users are gone.
  */
-static struct hd_struct *add_partition(struct gendisk *disk, int partno,
+static struct block_device *add_partition(struct gendisk *disk, int partno,
 				sector_t start, sector_t len, int flags,
 				struct partition_meta_info *info)
 {
-	struct hd_struct *p;
 	dev_t devt = MKDEV(0, 0);
 	struct device *ddev = disk_to_dev(disk);
 	struct device *pdev;
@@ -367,9 +360,6 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 	if (!bdev)
 		return ERR_PTR(-ENOMEM);
 
-	p = bdev->bd_part;
-	pdev = part_to_dev(p);
-
 	bdev->bd_start_sect = start;
 	bdev_set_nr_sectors(bdev, len);
 	bdev->bd_read_only = get_disk_ro(disk);
@@ -381,6 +371,7 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 			goto out_bdput;
 	}
 
+	pdev = &bdev->bd_device;
 	dname = dev_name(ddev);
 	if (isdigit(dname[strlen(dname) - 1]))
 		dev_set_name(pdev, "%sp%d", dname, partno);
@@ -422,7 +413,7 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 	/* suppress uevent if the disk suppresses it */
 	if (!dev_get_uevent_suppress(ddev))
 		kobject_uevent(&pdev->kobj, KOBJ_ADD);
-	return p;
+	return bdev;
 
 out_bdput:
 	bdput(bdev);
@@ -459,7 +450,7 @@ static bool partition_overlaps(struct gendisk *disk, sector_t start,
 int bdev_add_partition(struct block_device *bdev, int partno,
 		sector_t start, sector_t length)
 {
-	struct hd_struct *part;
+	struct block_device *part;
 
 	mutex_lock(&bdev->bd_mutex);
 	if (partition_overlaps(bdev->bd_disk, start, length, -1)) {
@@ -475,76 +466,59 @@ int bdev_add_partition(struct block_device *bdev, int partno,
 
 int bdev_del_partition(struct block_device *bdev, int partno)
 {
-	struct block_device *bdevp;
-	struct hd_struct *part = NULL;
+	struct block_device *part;
 	int ret;
 
-	bdevp = bdget_disk(bdev->bd_disk, partno);
-	if (!bdevp)
+	part = bdget_disk(bdev->bd_disk, partno);
+	if (!part)
 		return -ENXIO;
 
-	mutex_lock(&bdevp->bd_mutex);
+	mutex_lock(&part->bd_mutex);
 	mutex_lock_nested(&bdev->bd_mutex, 1);
 
-	ret = -ENXIO;
-	part = disk_get_part(bdev->bd_disk, partno);
-	if (!part)
-		goto out_unlock;
-
 	ret = -EBUSY;
-	if (bdevp->bd_openers)
+	if (part->bd_openers)
 		goto out_unlock;
 
-	sync_blockdev(bdevp);
-	invalidate_bdev(bdevp);
+	sync_blockdev(part);
+	invalidate_bdev(part);
 
 	delete_partition(part);
 	ret = 0;
 out_unlock:
 	mutex_unlock(&bdev->bd_mutex);
-	mutex_unlock(&bdevp->bd_mutex);
-	bdput(bdevp);
-	if (part)
-		disk_put_part(part);
+	mutex_unlock(&part->bd_mutex);
+	bdput(part);
 	return ret;
 }
 
 int bdev_resize_partition(struct block_device *bdev, int partno,
 		sector_t start, sector_t length)
 {
-	struct block_device *bdevp;
-	struct hd_struct *part;
+	struct block_device *part;
 	int ret = 0;
 
-	part = disk_get_part(bdev->bd_disk, partno);
+	part = bdget_disk(bdev->bd_disk, partno);
 	if (!part)
 		return -ENXIO;
 
-	ret = -ENOMEM;
-	bdevp = bdget_part(part);
-	if (!bdevp)
-		goto out_put_part;
-
-	mutex_lock(&bdevp->bd_mutex);
+	mutex_lock(&part->bd_mutex);
 	mutex_lock_nested(&bdev->bd_mutex, 1);
-
 	ret = -EINVAL;
-	if (start != part->bdev->bd_start_sect)
+	if (start != part->bd_start_sect)
 		goto out_unlock;
 
 	ret = -EBUSY;
 	if (partition_overlaps(bdev->bd_disk, start, length, partno))
 		goto out_unlock;
 
-	bdev_set_nr_sectors(bdevp, length);
+	bdev_set_nr_sectors(part, length);
 
 	ret = 0;
 out_unlock:
-	mutex_unlock(&bdevp->bd_mutex);
+	mutex_unlock(&part->bd_mutex);
 	mutex_unlock(&bdev->bd_mutex);
-	bdput(bdevp);
-out_put_part:
-	disk_put_part(part);
+	bdput(part);
 	return ret;
 }
 
@@ -577,7 +551,7 @@ int blk_drop_partitions(struct block_device *bdev)
 
 	disk_part_iter_init(&piter, bdev->bd_disk, DISK_PITER_INCL_EMPTY);
 	while ((part = disk_part_iter_next(&piter)))
-		delete_partition(part->bd_part);
+		delete_partition(part);
 	disk_part_iter_exit(&piter);
 
 	return 0;
@@ -592,7 +566,7 @@ static bool blk_add_partition(struct gendisk *disk, struct block_device *bdev,
 {
 	sector_t size = state->parts[p].size;
 	sector_t from = state->parts[p].from;
-	struct hd_struct *part;
+	struct block_device *part;
 
 	if (!size)
 		return true;
@@ -632,7 +606,7 @@ static bool blk_add_partition(struct gendisk *disk, struct block_device *bdev,
 
 	if (IS_BUILTIN(CONFIG_BLK_DEV_MD) &&
 	    (state->parts[p].flags & ADDPART_FLAG_RAID))
-		md_autodetect_dev(part_to_dev(part)->devt);
+		md_autodetect_dev(part->bd_dev);
 
 	return true;
 }
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 1538b20ca4bd43..08171478473ead 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -39,7 +39,6 @@
 
 struct bdev_inode {
 	struct block_device bdev;
-	struct hd_struct hd;
 	struct inode vfs_inode;
 };
 
@@ -886,9 +885,6 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
 		iput(inode);
 		return NULL;
 	}
-	bdev->bd_part = &BDEV_I(inode)->hd;
-	memset(bdev->bd_part, 0, sizeof(*bdev->bd_part));
-	bdev->bd_part->bdev = bdev;
 	return bdev;
 }
 
@@ -921,11 +917,6 @@ struct block_device *bdgrab(struct block_device *bdev)
 }
 EXPORT_SYMBOL(bdgrab);
 
-struct block_device *bdget_part(struct hd_struct *part)
-{
-	return bdget(part_devt(part));
-}
-
 long nr_blockdev_pages(void)
 {
 	struct inode *inode;
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 6edea5c1625909..866f74261b3ba8 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -8,6 +8,7 @@
 
 #include <linux/types.h>
 #include <linux/bvec.h>
+#include <linux/device.h>
 #include <linux/ktime.h>
 
 struct bio_set;
@@ -30,6 +31,7 @@ struct block_device {
 	struct super_block *	bd_super;
 	struct mutex		bd_mutex;	/* open/close mutex */
 	void *			bd_claiming;
+	struct device		bd_device;
 	void *			bd_holder;
 	int			bd_holders;
 	bool			bd_write_holder;
@@ -38,7 +40,6 @@ struct block_device {
 #endif
 	struct kobject		*bd_holder_dir;
 	u8			bd_partno;
-	struct hd_struct *	bd_part;
 	/* number of times partitions within this device have been opened. */
 	unsigned		bd_part_count;
 
@@ -61,8 +62,11 @@ struct block_device {
 #define bdev_whole(_bdev) \
 	((_bdev)->bd_disk->part0)
 
+#define dev_to_bdev(device) \
+	container_of((device), struct block_device, bd_device)
+
 #define bdev_kobj(_bdev) \
-	(&part_to_dev((_bdev)->bd_part)->kobj)
+	(&((_bdev)->bd_device.kobj))
 
 /*
  * Block error status values.  See block/blk-core:blk_errors for the details.
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 0e83989b9678c3..f390446919b745 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1995,7 +1995,6 @@ void blkdev_put(struct block_device *bdev, fmode_t mode);
 struct block_device *bdev_alloc(struct gendisk *disk, u8 partno);
 void bdev_add(struct block_device *bdev, dev_t dev);
 struct block_device *I_BDEV(struct inode *inode);
-struct block_device *bdget_part(struct hd_struct *part);
 struct block_device *bdgrab(struct block_device *bdev);
 void bdput(struct block_device *);
 
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index de2ee5ffeefe45..769dc22f574797 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -19,12 +19,6 @@
 #include <linux/blk_types.h>
 #include <asm/local.h>
 
-#define dev_to_part(device)	container_of((device), struct hd_struct, __dev)
-#define part_to_dev(part)	(&((part)->__dev))
-
-#define dev_to_disk(device)	(dev_to_part(device)->bdev->bd_disk)
-#define disk_to_dev(disk)	(part_to_dev((disk)->part0->bd_part))
-
 extern const struct device_type disk_type;
 extern struct device_type part_type;
 extern struct class block_class;
@@ -51,11 +45,6 @@ struct partition_meta_info {
 	u8 volname[PARTITION_META_INFO_VOLNAMELTH];
 };
 
-struct hd_struct {
-	struct block_device *bdev;
-	struct device __dev;
-};
-
 /**
  * DOC: genhd capability flags
  *
@@ -191,19 +180,21 @@ struct gendisk {
 	struct lockdep_map lockdep_map;
 };
 
+/*
+ * The gendisk is refcounted by the part0 block_device, and the bd_device
+ * therein is also used for device model presentation in sysfs.
+ */
+#define dev_to_disk(device) \
+	(dev_to_bdev(device)->bd_disk)
+#define disk_to_dev(disk) \
+	(&((disk)->part0->bd_device))
+
 #if IS_REACHABLE(CONFIG_CDROM)
 #define disk_to_cdi(disk)	((disk)->cdi)
 #else
 #define disk_to_cdi(disk)	NULL
 #endif
 
-static inline struct gendisk *part_to_disk(struct hd_struct *part)
-{
-	if (unlikely(!part))
-		return NULL;
-	return part->bdev->bd_disk;
-}
-
 static inline int disk_max_parts(struct gendisk *disk)
 {
 	if (disk->flags & GENHD_FL_EXT_DEVT)
@@ -222,19 +213,6 @@ static inline dev_t disk_devt(struct gendisk *disk)
 	return MKDEV(disk->major, disk->first_minor);
 }
 
-static inline dev_t part_devt(struct hd_struct *part)
-{
-	return part_to_dev(part)->devt;
-}
-
-extern struct hd_struct *disk_get_part(struct gendisk *disk, int partno);
-
-static inline void disk_put_part(struct hd_struct *part)
-{
-	if (likely(part))
-		put_device(part_to_dev(part));
-}
-
 /*
  * Smarter partition iterator without context limits.
  */
diff --git a/init/do_mounts.c b/init/do_mounts.c
index 86bef93e72ebd6..a78e44ee6adb8d 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -76,11 +76,11 @@ struct uuidcmp {
  */
 static int match_dev_by_uuid(struct device *dev, const void *data)
 {
+	struct block_device *bdev = dev_to_bdev(dev);
 	const struct uuidcmp *cmp = data;
-	struct hd_struct *part = dev_to_part(dev);
 
-	if (!part->bdev->bd_meta_info ||
-	    strncasecmp(cmp->uuid, part->bdev->bd_meta_info->uuid, cmp->len))
+	if (!bdev->bd_meta_info ||
+	    strncasecmp(cmp->uuid, bdev->bd_meta_info->uuid, cmp->len))
 		return 0;
 	return 1;
 }
@@ -133,13 +133,13 @@ static dev_t devt_from_partuuid(const char *uuid_str)
 		 * Attempt to find the requested partition by adding an offset
 		 * to the partition number found by UUID.
 		 */
-		struct hd_struct *part;
+		struct block_device *part;
 
-		part = disk_get_part(dev_to_disk(dev),
-				     dev_to_part(dev)->bdev->bd_partno + offset);
+		part = bdget_disk(dev_to_disk(dev),
+				  dev_to_bdev(dev)->bd_partno + offset);
 		if (part) {
-			devt = part_devt(part);
-			put_device(part_to_dev(part));
+			devt = part->bd_dev;
+			bdput(part);
 		}
 	} else {
 		devt = dev->devt;
@@ -166,11 +166,10 @@ static dev_t devt_from_partuuid(const char *uuid_str)
  */
 static int match_dev_by_label(struct device *dev, const void *data)
 {
+	struct block_device *bdev = dev_to_bdev(dev);
 	const char *label = data;
-	struct hd_struct *part = dev_to_part(dev);
 
-	if (!part->bdev->bd_meta_info ||
-	    strcmp(label, part->bdev->bd_meta_info->volname))
+	if (!bdev->bd_meta_info || strcmp(label, bdev->bd_meta_info->volname))
 		return 0;
 	return 1;
 }
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 8a723a91ec5a06..a482a37848bff7 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -1810,30 +1810,15 @@ static ssize_t blk_trace_mask2str(char *buf, int mask)
 	return p - buf;
 }
 
-static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
-{
-	if (bdev->bd_disk == NULL)
-		return NULL;
-
-	return bdev_get_queue(bdev);
-}
-
 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
 					 struct device_attribute *attr,
 					 char *buf)
 {
-	struct block_device *bdev = bdget_part(dev_to_part(dev));
-	struct request_queue *q;
+	struct block_device *bdev = dev_to_bdev(dev);
+	struct request_queue *q = bdev_get_queue(bdev);
 	struct blk_trace *bt;
 	ssize_t ret = -ENXIO;
 
-	if (bdev == NULL)
-		goto out;
-
-	q = blk_trace_get_queue(bdev);
-	if (q == NULL)
-		goto out_bdput;
-
 	mutex_lock(&q->debugfs_mutex);
 
 	bt = rcu_dereference_protected(q->blk_trace,
@@ -1856,9 +1841,6 @@ static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
 
 out_unlock_bdev:
 	mutex_unlock(&q->debugfs_mutex);
-out_bdput:
-	bdput(bdev);
-out:
 	return ret;
 }
 
@@ -1866,8 +1848,8 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
 					  struct device_attribute *attr,
 					  const char *buf, size_t count)
 {
-	struct block_device *bdev;
-	struct request_queue *q;
+	struct block_device *bdev = dev_to_bdev(dev);
+	struct request_queue *q = bdev_get_queue(bdev);
 	struct blk_trace *bt;
 	u64 value;
 	ssize_t ret = -EINVAL;
@@ -1883,17 +1865,10 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
 				goto out;
 			value = ret;
 		}
-	} else if (kstrtoull(buf, 0, &value))
-		goto out;
-
-	ret = -ENXIO;
-	bdev = bdget_part(dev_to_part(dev));
-	if (bdev == NULL)
-		goto out;
-
-	q = blk_trace_get_queue(bdev);
-	if (q == NULL)
-		goto out_bdput;
+	} else {
+		if (kstrtoull(buf, 0, &value))
+			goto out;
+	}
 
 	mutex_lock(&q->debugfs_mutex);
 
@@ -1931,8 +1906,6 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
 
 out_unlock_bdev:
 	mutex_unlock(&q->debugfs_mutex);
-out_bdput:
-	bdput(bdev);
 out:
 	return ret ? ret : count;
 }
-- 
2.29.2

--
dm-devel mailing list
dm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel


^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 45/45] block: stop using bdget_disk for partition 0
  2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
                   ` (43 preceding siblings ...)
  2020-11-24 13:27 ` [dm-devel] [PATCH 44/45] block: merge struct block_device and struct hd_struct Christoph Hellwig
@ 2020-11-24 13:27 ` Christoph Hellwig
  44 siblings, 0 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-24 13:27 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

We can just dereference the point in struct gendisk instead.  Also
remove the now unused export.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 block/genhd.c                   |  1 -
 drivers/block/nbd.c             |  4 +---
 drivers/block/xen-blkfront.c    | 20 +++++---------------
 drivers/block/zram/zram_drv.c   | 18 +++---------------
 drivers/md/dm.c                 | 16 ++--------------
 drivers/s390/block/dasd_ioctl.c |  5 ++---
 6 files changed, 13 insertions(+), 51 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index e1f67b9951f0ec..9a3ad1895888c6 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -912,7 +912,6 @@ struct block_device *bdget_disk(struct gendisk *disk, int partno)
 
 	return bdev;
 }
-EXPORT_SYMBOL(bdget_disk);
 
 /*
  * print a full list of all partitions - intended for places where the root
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 014683968ce174..92f84ed0ba9eb6 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -1488,12 +1488,10 @@ static int nbd_open(struct block_device *bdev, fmode_t mode)
 static void nbd_release(struct gendisk *disk, fmode_t mode)
 {
 	struct nbd_device *nbd = disk->private_data;
-	struct block_device *bdev = bdget_disk(disk, 0);
 
 	if (test_bit(NBD_RT_DISCONNECT_ON_CLOSE, &nbd->config->runtime_flags) &&
-			bdev->bd_openers == 0)
+			disk->part0->bd_openers == 0)
 		nbd_disconnect_and_put(nbd);
-	bdput(bdev);
 
 	nbd_config_put(nbd);
 	nbd_put(nbd);
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 79521e33d30ed5..188e0b47534bcf 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -2153,7 +2153,7 @@ static void blkfront_closing(struct blkfront_info *info)
 	}
 
 	if (info->gd)
-		bdev = bdget_disk(info->gd, 0);
+		bdev = bdgrab(info->gd->part0);
 
 	mutex_unlock(&info->mutex);
 
@@ -2518,7 +2518,7 @@ static int blkfront_remove(struct xenbus_device *xbdev)
 
 	disk = info->gd;
 	if (disk)
-		bdev = bdget_disk(disk, 0);
+		bdev = bdgrab(disk->part0);
 
 	info->xbdev = NULL;
 	mutex_unlock(&info->mutex);
@@ -2595,19 +2595,11 @@ static int blkif_open(struct block_device *bdev, fmode_t mode)
 static void blkif_release(struct gendisk *disk, fmode_t mode)
 {
 	struct blkfront_info *info = disk->private_data;
-	struct block_device *bdev;
 	struct xenbus_device *xbdev;
 
 	mutex_lock(&blkfront_mutex);
-
-	bdev = bdget_disk(disk, 0);
-
-	if (!bdev) {
-		WARN(1, "Block device %s yanked out from us!\n", disk->disk_name);
+	if (disk->part0->bd_openers)
 		goto out_mutex;
-	}
-	if (bdev->bd_openers)
-		goto out;
 
 	/*
 	 * Check if we have been instructed to close. We will have
@@ -2619,7 +2611,7 @@ static void blkif_release(struct gendisk *disk, fmode_t mode)
 
 	if (xbdev && xbdev->state == XenbusStateClosing) {
 		/* pending switch to state closed */
-		dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
+		dev_info(disk_to_dev(disk), "releasing disk\n");
 		xlvbd_release_gendisk(info);
 		xenbus_frontend_closed(info->xbdev);
  	}
@@ -2628,14 +2620,12 @@ static void blkif_release(struct gendisk *disk, fmode_t mode)
 
 	if (!xbdev) {
 		/* sudden device removal */
-		dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
+		dev_info(disk_to_dev(disk), "releasing disk\n");
 		xlvbd_release_gendisk(info);
 		disk->private_data = NULL;
 		free_info(info);
 	}
 
-out:
-	bdput(bdev);
 out_mutex:
 	mutex_unlock(&blkfront_mutex);
 }
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 01757f9578dcb8..56024905bd242c 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1748,7 +1748,7 @@ static ssize_t reset_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t len)
 {
 	struct zram *zram = dev_to_zram(dev);
-	struct block_device *bdev;
+	struct block_device *bdev = zram->disk->part0;
 	unsigned short do_reset;
 	int ret = 0;
 
@@ -1758,17 +1758,12 @@ static ssize_t reset_store(struct device *dev,
 	if (!do_reset)
 		return -EINVAL;
 
-	bdev = bdget_disk(zram->disk, 0);
-	if (!bdev)
-		return -ENOMEM;
-
 	mutex_lock(&bdev->bd_mutex);
 	if (bdev->bd_openers)
 		ret = -EBUSY;
 	else
 		zram_reset_device(zram);
 	mutex_unlock(&bdev->bd_mutex);
-	bdput(bdev);
 
 	return ret ? ret : len;
 }
@@ -1933,15 +1928,8 @@ static int zram_add(void)
 
 static int zram_remove(struct zram *zram)
 {
-	struct block_device *bdev = bdget_disk(zram->disk, 0);
-
-	if (bdev) {
-		if (bdev->bd_openers) {
-			bdput(bdev);
-			return -EBUSY;
-		}
-		bdput(bdev);
-	}
+	if (zram->disk->part0->bd_openers)
+		return -EBUSY;
 
 	del_gendisk(zram->disk);
 	zram_debugfs_unregister(zram);
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 176adcff56b380..ed7e836efbcdbc 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2375,16 +2375,11 @@ struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
  */
 static int lock_fs(struct mapped_device *md)
 {
-	struct block_device *bdev;
 	int r;
 
 	WARN_ON(test_bit(DMF_FROZEN, &md->flags));
 
-	bdev = bdget_disk(md->disk, 0);
-	if (!bdev)
-		return -ENOMEM;
-	r = freeze_bdev(bdev);
-	bdput(bdev);
+	r = freeze_bdev(md->disk->part0);
 	if (!r)
 		set_bit(DMF_FROZEN, &md->flags);
 	return r;
@@ -2392,16 +2387,9 @@ static int lock_fs(struct mapped_device *md)
 
 static void unlock_fs(struct mapped_device *md)
 {
-	struct block_device *bdev;
-
 	if (!test_bit(DMF_FROZEN, &md->flags))
 		return;
-
-	bdev = bdget_disk(md->disk, 0);
-	if (!bdev)
-		return;
-	thaw_bdev(bdev);
-	bdput(bdev);
+	thaw_bdev(md->disk->part0);
 	clear_bit(DMF_FROZEN, &md->flags);
 }
 
diff --git a/drivers/s390/block/dasd_ioctl.c b/drivers/s390/block/dasd_ioctl.c
index 304eba1acf163c..9f642440894655 100644
--- a/drivers/s390/block/dasd_ioctl.c
+++ b/drivers/s390/block/dasd_ioctl.c
@@ -220,9 +220,8 @@ dasd_format(struct dasd_block *block, struct format_data_t *fdata)
 	 * enabling the device later.
 	 */
 	if (fdata->start_unit == 0) {
-		struct block_device *bdev = bdget_disk(block->gdp, 0);
-		bdev->bd_inode->i_blkbits = blksize_bits(fdata->blksize);
-		bdput(bdev);
+		block->gdp->part0->bd_inode->i_blkbits =
+			blksize_bits(fdata->blksize);
 	}
 
 	rc = base->discipline->format_device(base, fdata, 1);
-- 
2.29.2

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 38/45] block: switch partition lookup to use struct block_device
  2020-11-24 13:27 ` [dm-devel] [PATCH 38/45] block: switch partition lookup to use struct block_device Christoph Hellwig
@ 2020-11-24 13:32   ` Coly Li
  2020-11-25  6:11   ` Chao Yu
  1 sibling, 0 replies; 92+ messages in thread
From: Coly Li @ 2020-11-24 13:32 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

On 11/24/20 9:27 PM, Christoph Hellwig wrote:
> Use struct block_device to lookup partitions on a disk.  This removes
> all usage of struct hd_struct from the I/O path, and this allows removing
> the percpu refcount in struct hd_struct.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>


For the bcache part, Acked-by: Coly Li <colyli@suse.de>

> ---
>  block/bio.c                        |  4 +-
>  block/blk-core.c                   | 66 ++++++++++++++----------------
>  block/blk-flush.c                  |  2 +-
>  block/blk-mq.c                     |  9 ++--
>  block/blk-mq.h                     |  7 ++--
>  block/blk.h                        |  4 +-
>  block/genhd.c                      | 56 +++++++++++++------------
>  block/partitions/core.c            |  7 +---
>  drivers/block/drbd/drbd_receiver.c |  2 +-
>  drivers/block/drbd/drbd_worker.c   |  2 +-
>  drivers/block/zram/zram_drv.c      |  2 +-
>  drivers/md/bcache/request.c        |  4 +-
>  drivers/md/dm.c                    |  4 +-
>  drivers/md/md.c                    |  4 +-
>  drivers/nvme/target/admin-cmd.c    | 20 ++++-----
>  fs/ext4/super.c                    | 18 +++-----
>  fs/ext4/sysfs.c                    | 10 +----
>  fs/f2fs/f2fs.h                     |  2 +-
>  fs/f2fs/super.c                    |  6 +--
>  include/linux/blkdev.h             |  8 ++--
>  include/linux/genhd.h              |  4 +-
>  include/linux/part_stat.h          | 17 ++++----
>  22 files changed, 120 insertions(+), 138 deletions(-)
[snipped]

> diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
> index afac8d07c1bd00..85b1f2a9b72d68 100644
> --- a/drivers/md/bcache/request.c
> +++ b/drivers/md/bcache/request.c
> @@ -475,7 +475,7 @@ struct search {
>  	unsigned int		read_dirty_data:1;
>  	unsigned int		cache_missed:1;
>  
> -	struct hd_struct	*part;
> +	struct block_device	*part;
>  	unsigned long		start_time;
>  
>  	struct btree_op		op;
> @@ -1073,7 +1073,7 @@ struct detached_dev_io_private {
>  	unsigned long		start_time;
>  	bio_end_io_t		*bi_end_io;
>  	void			*bi_private;
> -	struct hd_struct	*part;
> +	struct block_device	*part;
>  };
[snipped]

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 30/45] block: remove the nr_sects field in struct hd_struct
  2020-11-24 13:27 ` [dm-devel] [PATCH 30/45] block: remove the nr_sects field in struct hd_struct Christoph Hellwig
@ 2020-11-24 13:34   ` Coly Li
  2020-11-25  6:10   ` Chao Yu
  1 sibling, 0 replies; 92+ messages in thread
From: Coly Li @ 2020-11-24 13:34 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

On 11/24/20 9:27 PM, Christoph Hellwig wrote:
> Now that the hd_struct always has a block device attached to it, there is
> no need for having two size field that just get out of sync.
> 
> Additional the field in hd_struct did not use proper serializiation,
> possibly allowing for torn writes.  By only using the block_device field
> this problem also gets fixed.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

For the bcache part, Acked-by: Coly Li <colyli@suse.de>

Thanks.

Coly Li

> ---
>  block/bio.c                        |  4 +-
>  block/blk-core.c                   |  2 +-
>  block/blk.h                        | 53 ----------------------
>  block/genhd.c                      | 55 +++++++++++-----------
>  block/partitions/core.c            | 17 ++++---
>  drivers/block/loop.c               |  1 -
>  drivers/block/nbd.c                |  2 +-
>  drivers/block/xen-blkback/common.h |  4 +-
>  drivers/md/bcache/super.c          |  2 +-
>  drivers/s390/block/dasd_ioctl.c    |  4 +-
>  drivers/target/target_core_pscsi.c |  7 +--
>  fs/block_dev.c                     | 73 +-----------------------------
>  fs/f2fs/super.c                    |  2 +-
>  fs/pstore/blk.c                    |  2 +-
>  include/linux/genhd.h              | 29 +++---------
>  kernel/trace/blktrace.c            |  2 +-
>  16 files changed, 60 insertions(+), 199 deletions(-)
> 
[snipped]

> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
> index c55d3c58a7ef55..04fa40868fbe10 100644
> --- a/drivers/md/bcache/super.c
> +++ b/drivers/md/bcache/super.c
> @@ -1408,7 +1408,7 @@ static int cached_dev_init(struct cached_dev *dc, unsigned int block_size)
>  			q->limits.raid_partial_stripes_expensive;
>  
>  	ret = bcache_device_init(&dc->disk, block_size,
> -			 dc->bdev->bd_part->nr_sects - dc->sb.data_offset,
> +			 bdev_nr_sectors(dc->bdev) - dc->sb.data_offset,
>  			 dc->bdev, &bcache_cached_ops);
>  	if (ret)
>  		return ret;
[snipped]

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 23/45] block: remove i_bdev
  2020-11-24 13:27 ` [dm-devel] [PATCH 23/45] block: remove i_bdev Christoph Hellwig
@ 2020-11-24 13:38   ` Coly Li
  2020-11-24 19:37   ` Tejun Heo
  1 sibling, 0 replies; 92+ messages in thread
From: Coly Li @ 2020-11-24 13:38 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

On 11/24/20 9:27 PM, Christoph Hellwig wrote:
> Switch the block device lookup interfaces to directly work with a dev_t
> so that struct block_device references are only acquired by the
> blkdev_get variants (and the blk-cgroup special case).  This means that
> we not don't need an extra reference in the inode and can generally
> simplify handling of struct block_device to keep the lookups contained
> in the core block layer code.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

For the bcache part, Acked-by: Coly Li <colyli@suse.de>

Thanks.

Coly Li

> ---
>  block/ioctl.c                                |   3 +-
>  drivers/block/loop.c                         |   8 +-
>  drivers/md/bcache/super.c                    |  20 +-
>  drivers/md/dm-table.c                        |   9 +-
>  drivers/mtd/mtdsuper.c                       |  17 +-
>  drivers/target/target_core_file.c            |   6 +-
>  drivers/usb/gadget/function/storage_common.c |   8 +-
>  fs/block_dev.c                               | 195 +++++--------------
>  fs/btrfs/volumes.c                           |  13 +-
>  fs/inode.c                                   |   3 -
>  fs/internal.h                                |   7 +-
>  fs/io_uring.c                                |  10 +-
>  fs/pipe.c                                    |   5 +-
>  fs/quota/quota.c                             |  19 +-
>  fs/statfs.c                                  |   2 +-
>  fs/super.c                                   |  37 ++--
>  include/linux/blkdev.h                       |   2 +-
>  include/linux/fs.h                           |   1 -
>  18 files changed, 114 insertions(+), 251 deletions(-)
> 

[snipped]

> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
> index a6a5e21e4fd136..c55d3c58a7ef55 100644
> --- a/drivers/md/bcache/super.c
> +++ b/drivers/md/bcache/super.c
> @@ -2380,38 +2380,38 @@ kobj_attribute_write(register,		register_bcache);
>  kobj_attribute_write(register_quiet,	register_bcache);
>  kobj_attribute_write(pendings_cleanup,	bch_pending_bdevs_cleanup);
>  
> -static bool bch_is_open_backing(struct block_device *bdev)
> +static bool bch_is_open_backing(dev_t dev)
>  {
>  	struct cache_set *c, *tc;
>  	struct cached_dev *dc, *t;
>  
>  	list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
>  		list_for_each_entry_safe(dc, t, &c->cached_devs, list)
> -			if (dc->bdev == bdev)
> +			if (dc->bdev->bd_dev == dev)
>  				return true;
>  	list_for_each_entry_safe(dc, t, &uncached_devices, list)
> -		if (dc->bdev == bdev)
> +		if (dc->bdev->bd_dev == dev)
>  			return true;
>  	return false;
>  }
>  
> -static bool bch_is_open_cache(struct block_device *bdev)
> +static bool bch_is_open_cache(dev_t dev)
>  {
>  	struct cache_set *c, *tc;
>  
>  	list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
>  		struct cache *ca = c->cache;
>  
> -		if (ca->bdev == bdev)
> +		if (ca->bdev->bd_dev == dev)
>  			return true;
>  	}
>  
>  	return false;
>  }
>  
> -static bool bch_is_open(struct block_device *bdev)
> +static bool bch_is_open(dev_t dev)
>  {
> -	return bch_is_open_cache(bdev) || bch_is_open_backing(bdev);
> +	return bch_is_open_cache(dev) || bch_is_open_backing(dev);
>  }
>  
>  struct async_reg_args {
> @@ -2535,9 +2535,11 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
>  				  sb);
>  	if (IS_ERR(bdev)) {
>  		if (bdev == ERR_PTR(-EBUSY)) {
> -			bdev = lookup_bdev(strim(path));
> +			dev_t dev;
> +
>  			mutex_lock(&bch_register_lock);
> -			if (!IS_ERR(bdev) && bch_is_open(bdev))
> +			if (lookup_bdev(strim(path), &dev) == 0 &&
> +			    bch_is_open(dev))
>  				err = "device already registered";
>  			else
>  				err = "device busy";
[snipped]

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 13/45] block: add a bdev_kobj helper
  2020-11-24 13:27 ` [dm-devel] [PATCH 13/45] block: add a bdev_kobj helper Christoph Hellwig
@ 2020-11-24 13:41   ` Coly Li
  2020-11-24 17:37   ` Tejun Heo
  1 sibling, 0 replies; 92+ messages in thread
From: Coly Li @ 2020-11-24 13:41 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

On 11/24/20 9:27 PM, Christoph Hellwig wrote:
> Add a little helper to find the kobject for a struct block_device.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Reviewed-by: Jan Kara <jack@suse.cz>
> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

For the bcache part, Acked-by: Coly Li <colyli@suse.de>

Thanks.

Coly Li

> ---
>  drivers/md/bcache/super.c |  7 ++-----
>  drivers/md/md.c           |  4 +---
>  fs/block_dev.c            |  6 +++---
>  fs/btrfs/sysfs.c          | 15 +++------------
>  include/linux/blk_types.h |  3 +++
>  5 files changed, 12 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
> index 46a00134a36ae1..a6a5e21e4fd136 100644
> --- a/drivers/md/bcache/super.c
> +++ b/drivers/md/bcache/super.c
> @@ -1447,8 +1447,7 @@ static int register_bdev(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
>  		goto err;
>  
>  	err = "error creating kobject";
> -	if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj,
> -			"bcache"))
> +	if (kobject_add(&dc->disk.kobj, bdev_kobj(bdev), "bcache"))
>  		goto err;
>  	if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj))
>  		goto err;
> @@ -2342,9 +2341,7 @@ static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
>  		goto err;
>  	}
>  
> -	if (kobject_add(&ca->kobj,
> -			&part_to_dev(bdev->bd_part)->kobj,
> -			"bcache")) {
> +	if (kobject_add(&ca->kobj, bdev_kobj(bdev), "bcache")) {
>  		err = "error calling kobject_add";
>  		ret = -ENOMEM;
>  		goto out;

[snipped]

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 02/45] filemap: consistently use ->f_mapping over ->i_mapping
  2020-11-24 13:27 ` [dm-devel] [PATCH 02/45] filemap: consistently use ->f_mapping over ->i_mapping Christoph Hellwig
@ 2020-11-24 13:53   ` Matthew Wilcox
  2020-11-25  6:41   ` Hannes Reinecke
  2020-11-25 12:16   ` Jan Kara
  2 siblings, 0 replies; 92+ messages in thread
From: Matthew Wilcox @ 2020-11-24 13:53 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-bcache, linux-mm

On Tue, Nov 24, 2020 at 02:27:08PM +0100, Christoph Hellwig wrote:
> Use file->f_mapping in all remaining places that have a struct file
> available to properly handle the case where inode->i_mapping !=
> file_inode(file)->i_mapping.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 11/45] block: remove a duplicate __disk_get_part prototype
  2020-11-24 13:27 ` [dm-devel] [PATCH 11/45] block: remove a duplicate __disk_get_part prototype Christoph Hellwig
@ 2020-11-24 17:36   ` Tejun Heo
  0 siblings, 0 replies; 92+ messages in thread
From: Tejun Heo @ 2020-11-24 17:36 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

On Tue, Nov 24, 2020 at 02:27:17PM +0100, Christoph Hellwig wrote:
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Reviewed-by: Jan Kara <jack@suse.cz>
> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

Acked-by: Tejun Heo <tj@kernel.org>

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 12/45] block: remove a superflous check in blkpg_do_ioctl
  2020-11-24 13:27 ` [dm-devel] [PATCH 12/45] block: remove a superflous check in blkpg_do_ioctl Christoph Hellwig
@ 2020-11-24 17:37   ` Tejun Heo
  2020-11-25 13:39   ` Jan Kara
  1 sibling, 0 replies; 92+ messages in thread
From: Tejun Heo @ 2020-11-24 17:37 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

On Tue, Nov 24, 2020 at 02:27:18PM +0100, Christoph Hellwig wrote:
> sector_t is now always a u64, so this check is not needed.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Acked-by: Tejun Heo <tj@kernel.org>

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 13/45] block: add a bdev_kobj helper
  2020-11-24 13:27 ` [dm-devel] [PATCH 13/45] block: add a bdev_kobj helper Christoph Hellwig
  2020-11-24 13:41   ` Coly Li
@ 2020-11-24 17:37   ` Tejun Heo
  1 sibling, 0 replies; 92+ messages in thread
From: Tejun Heo @ 2020-11-24 17:37 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

On Tue, Nov 24, 2020 at 02:27:19PM +0100, Christoph Hellwig wrote:
> Add a little helper to find the kobject for a struct block_device.

Acked-by: Tejun Heo <tj@kernel.org>

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 14/45] block: use disk_part_iter_exit in disk_part_iter_next
  2020-11-24 13:27 ` [dm-devel] [PATCH 14/45] block: use disk_part_iter_exit in disk_part_iter_next Christoph Hellwig
@ 2020-11-24 17:37   ` Tejun Heo
  0 siblings, 0 replies; 92+ messages in thread
From: Tejun Heo @ 2020-11-24 17:37 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

On Tue, Nov 24, 2020 at 02:27:20PM +0100, Christoph Hellwig wrote:
> Call disk_part_iter_exit in disk_part_iter_next instead of duplicating
> the functionality.

Acked-by: Tejun Heo <tj@kernel.org>

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 15/45] block: use put_device in put_disk
  2020-11-24 13:27 ` [dm-devel] [PATCH 15/45] block: use put_device in put_disk Christoph Hellwig
@ 2020-11-24 17:37   ` Tejun Heo
  0 siblings, 0 replies; 92+ messages in thread
From: Tejun Heo @ 2020-11-24 17:37 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

On Tue, Nov 24, 2020 at 02:27:21PM +0100, Christoph Hellwig wrote:
> Use put_device to put the device instead of poking into the internals
> and using kobject_put.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Reviewed-by: Jan Kara <jack@suse.cz>
> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

Acked-by: Tejun Heo <tj@kernel.org>

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 16/45] block: change the hash used for looking up block devices
  2020-11-24 13:27 ` [dm-devel] [PATCH 16/45] block: change the hash used for looking up block devices Christoph Hellwig
@ 2020-11-24 17:38   ` Tejun Heo
  0 siblings, 0 replies; 92+ messages in thread
From: Tejun Heo @ 2020-11-24 17:38 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

On Tue, Nov 24, 2020 at 02:27:22PM +0100, Christoph Hellwig wrote:
> Adding the minor to the major creates tons of pointless conflicts. Just
> use the dev_t itself, which is 32-bits and thus is guaranteed to fit
> into ino_t.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Reviewed-by: Jan Kara <jack@suse.cz>

Acked-by: Tejun Heo <tj@kernel.org>

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 17/45] init: refactor name_to_dev_t
  2020-11-24 13:27 ` [dm-devel] [PATCH 17/45] init: refactor name_to_dev_t Christoph Hellwig
@ 2020-11-24 17:38   ` Tejun Heo
  0 siblings, 0 replies; 92+ messages in thread
From: Tejun Heo @ 2020-11-24 17:38 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

On Tue, Nov 24, 2020 at 02:27:23PM +0100, Christoph Hellwig wrote:
> Split each case into a self-contained helper, and move the block
> dependent code entirely under the pre-existing #ifdef CONFIG_BLOCK.
> This allows to remove the blk_lookup_devt stub in genhd.h.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Reviewed-by: Jan Kara <jack@suse.cz>
> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

Acked-by: Tejun Heo <tj@kernel.org>

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 18/45] init: refactor devt_from_partuuid
  2020-11-24 13:27 ` [dm-devel] [PATCH 18/45] init: refactor devt_from_partuuid Christoph Hellwig
@ 2020-11-24 17:38   ` Tejun Heo
  0 siblings, 0 replies; 92+ messages in thread
From: Tejun Heo @ 2020-11-24 17:38 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

On Tue, Nov 24, 2020 at 02:27:24PM +0100, Christoph Hellwig wrote:
> The code in devt_from_partuuid is very convoluted.  Refactor a bit by
> sanitizing the goto and variable name usage.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Reviewed-by: Jan Kara <jack@suse.cz>

Acked-by: Tejun Heo <tj@kernel.org>

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 19/45] init: cleanup match_dev_by_uuid and match_dev_by_label
  2020-11-24 13:27 ` [dm-devel] [PATCH 19/45] init: cleanup match_dev_by_uuid and match_dev_by_label Christoph Hellwig
@ 2020-11-24 17:39   ` Tejun Heo
  0 siblings, 0 replies; 92+ messages in thread
From: Tejun Heo @ 2020-11-24 17:39 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

On Tue, Nov 24, 2020 at 02:27:25PM +0100, Christoph Hellwig wrote:
> Avoid a totally pointless goto label, and use the same style of
> comparism for both helpers.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Reviewed-by: Jan Kara <jack@suse.cz>
> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

Acked-by: Tejun Heo <tj@kernel.org>

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 20/45] block: refactor __blkdev_put
  2020-11-24 13:27 ` [dm-devel] [PATCH 20/45] block: refactor __blkdev_put Christoph Hellwig
@ 2020-11-24 17:41   ` Tejun Heo
  0 siblings, 0 replies; 92+ messages in thread
From: Tejun Heo @ 2020-11-24 17:41 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

On Tue, Nov 24, 2020 at 02:27:26PM +0100, Christoph Hellwig wrote:
> Reorder the code to have one big section for the last close, and to use
> bdev_is_partition.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Reviewed-by: Jan Kara <jack@suse.cz>

Acked-by: Tejun Heo <tj@kernel.org>

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 21/45] block: refactor blkdev_get
  2020-11-24 13:27 ` [dm-devel] [PATCH 21/45] block: refactor blkdev_get Christoph Hellwig
@ 2020-11-24 18:03   ` Tejun Heo
  0 siblings, 0 replies; 92+ messages in thread
From: Tejun Heo @ 2020-11-24 18:03 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

On Tue, Nov 24, 2020 at 02:27:27PM +0100, Christoph Hellwig wrote:
> Move more code that is only run on the outer open but not the open of
> the underlying whole device when opening a partition into blkdev_get,
> which leads to a much easier to follow structure.
> 
> This allows to simplify the disk and module refcounting so that one
> reference is held for each open, similar to what we do with normal
> file operations.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 22/45] block: opencode devcgroup_inode_permission
  2020-11-24 13:27 ` [dm-devel] [PATCH 22/45] block: opencode devcgroup_inode_permission Christoph Hellwig
@ 2020-11-24 18:05   ` Tejun Heo
  0 siblings, 0 replies; 92+ messages in thread
From: Tejun Heo @ 2020-11-24 18:05 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

On Tue, Nov 24, 2020 at 02:27:28PM +0100, Christoph Hellwig wrote:
> Just call devcgroup_check_permission to avoid various superflous checks
> and a double conversion of the access flags.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Acked-by: Tejun Heo <tj@kernel.org>

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 23/45] block: remove i_bdev
  2020-11-24 13:27 ` [dm-devel] [PATCH 23/45] block: remove i_bdev Christoph Hellwig
  2020-11-24 13:38   ` Coly Li
@ 2020-11-24 19:37   ` Tejun Heo
  2020-11-25 16:29     ` Christoph Hellwig
  1 sibling, 1 reply; 92+ messages in thread
From: Tejun Heo @ 2020-11-24 19:37 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

On Tue, Nov 24, 2020 at 02:27:29PM +0100, Christoph Hellwig wrote:
> Switch the block device lookup interfaces to directly work with a dev_t
> so that struct block_device references are only acquired by the
> blkdev_get variants (and the blk-cgroup special case).  This means that
> we not don't need an extra reference in the inode and can generally
     ^
     now
> simplify handling of struct block_device to keep the lookups contained
> in the core block layer code.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
...
> @@ -1689,14 +1599,12 @@ static int blkdev_open(struct inode * inode, struct file * filp)
>  	if ((filp->f_flags & O_ACCMODE) == 3)
>  		filp->f_mode |= FMODE_WRITE_IOCTL;
>  
> -	bdev = bd_acquire(inode);
> -	if (bdev == NULL)
> -		return -ENOMEM;
> -
> +	bdev = blkdev_get_by_dev(inode->i_rdev, filp->f_mode, filp);
> +	if (IS_ERR(bdev))
> +		return PTR_ERR(bdev);
>  	filp->f_mapping = bdev->bd_inode->i_mapping;
>  	filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
> -
> -	return blkdev_get(bdev, filp->f_mode, filp);
> +	return 0;
>  }

I was wondering whether losing the stale bdev flushing in bd_acquire() would
cause user-visible behavior changes but can't see how it would given that
userland has no way of holding onto a specific instance of block inode.
Maybe it's something worth mentioning in the commit message?

Other than that, for the block part:

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 24/45] blk-cgroup: stop abusing get_gendisk
  2020-11-24 13:27 ` [dm-devel] [PATCH 24/45] blk-cgroup: stop abusing get_gendisk Christoph Hellwig
@ 2020-11-24 19:46   ` Tejun Heo
  0 siblings, 0 replies; 92+ messages in thread
From: Tejun Heo @ 2020-11-24 19:46 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

On Tue, Nov 24, 2020 at 02:27:30PM +0100, Christoph Hellwig wrote:
> Properly open the device instead of relying on deep internals by
> using get_gendisk.  Note that this uses FMODE_NDELAY without either
> FMODE_READ or FMODE_WRITE, which is a special open mode to allow
> for opening without media access, thus avoiding unexpexted interactions
> especially on removable media.

I'm not sure FMODE_NDELAY does that. e.g. sd_open() does media change check
and full revalidation including disk spin up regadless of NDELAY and it's
odd and can lead to nasty surprises to require cgroup configuration updates
to wait for SCSI EH.

Thanks.

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 25/45] block: reference struct block_device from struct hd_struct
  2020-11-24 13:27 ` [dm-devel] [PATCH 25/45] block: reference struct block_device from struct hd_struct Christoph Hellwig
@ 2020-11-24 21:18   ` Tejun Heo
  2020-11-25 16:45     ` Christoph Hellwig
  0 siblings, 1 reply; 92+ messages in thread
From: Tejun Heo @ 2020-11-24 21:18 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

Hello,

Please see lkml.kernel.org/r/X708BTJ5njtbC2z1@mtj.duckdns.org for a few nits
on the previous version.

On Tue, Nov 24, 2020 at 02:27:31PM +0100, Christoph Hellwig wrote:
> To simplify block device lookup and a few other upcoming areas, make sure
> that we always have a struct block_device available for each disk and
> each partition.  The only downside of this is that each device and
> partition uses a little more memory.  The upside will be that a lot of
> code can be simplified.
> 
> With that all we need to look up the block device is to lookup the inode
> and do a few sanity checks on the gendisk, instead of the separate lookup
> for the gendisk.  These checks are in a new RCU critical section and
> the disk is now freed using kfree_rcu().

I might be confused but am wondering whether RCU is needed. It's currently
used to ensure that gendisk is accessible in the blkdev_get path but
wouldn't it be possible to simply pin gendisk from block_devices? The
gendisk and hd_structs hold the base refs of the block_devices and in turn
the block_devices pin the gendisk. When the gendisk gets deleted, it puts
the base refs of the block devices but stays around while the block devices
are being accessed.

Also, would it make sense to separate out lookup_sem removal? I *think* it's
there to ensure that the same bdev doesn't get associated with old and new
gendisks at the same time but can't wrap my head around how it works
exactly. I can see that this may not be needed once the lifetimes of gendisk
and block_devices are tied together but that may warrant a bit more
explanation.

Thanks.

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 26/45] block: remove ->bd_contains
  2020-11-24 13:27 ` [dm-devel] [PATCH 26/45] block: remove ->bd_contains Christoph Hellwig
@ 2020-11-24 21:19   ` Tejun Heo
  0 siblings, 0 replies; 92+ messages in thread
From: Tejun Heo @ 2020-11-24 21:19 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

On Tue, Nov 24, 2020 at 02:27:32PM +0100, Christoph Hellwig wrote:
> Now that each hd_struct has a reference to the corresponding
> block_device, there is no need for the bd_contains pointer.  Add
> a bdev_whole() helper to look up the whole device block_device
> struture instead.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Reviewed-by: Jan Kara <jack@suse.cz>

Acked-by: Tejun Heo <tj@kernel.org>

-- 
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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 27/45] block: simplify the block device claiming interface
  2020-11-24 13:27 ` [dm-devel] [PATCH 27/45] block: simplify the block device claiming interface Christoph Hellwig
@ 2020-11-24 21:19   ` Tejun Heo
  0 siblings, 0 replies; 92+ messages in thread
From: Tejun Heo @ 2020-11-24 21:19 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

On Tue, Nov 24, 2020 at 02:27:33PM +0100, Christoph Hellwig wrote:
> Stop passing the whole device as a separate argument given that it
> can be trivially deducted and cleanup the !holder debug check.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Reviewed-by: Jan Kara <jack@suse.cz>

Acked-by: Tejun Heo <tj@kernel.org>

-- 
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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 28/45] block: simplify part_to_disk
  2020-11-24 13:27 ` [dm-devel] [PATCH 28/45] block: simplify part_to_disk Christoph Hellwig
@ 2020-11-24 21:20   ` Tejun Heo
  0 siblings, 0 replies; 92+ messages in thread
From: Tejun Heo @ 2020-11-24 21:20 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

On Tue, Nov 24, 2020 at 02:27:34PM +0100, Christoph Hellwig wrote:
> Now that struct hd_struct has a block_device pointer use that to
> find the disk.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Acked-by: Tejun Heo <tj@kernel.org>

-- 
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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 29/45] block: initialize struct block_device in bdev_alloc
  2020-11-24 13:27 ` [dm-devel] [PATCH 29/45] block: initialize struct block_device in bdev_alloc Christoph Hellwig
@ 2020-11-24 21:20   ` Tejun Heo
  0 siblings, 0 replies; 92+ messages in thread
From: Tejun Heo @ 2020-11-24 21:20 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

On Tue, Nov 24, 2020 at 02:27:35PM +0100, Christoph Hellwig wrote:
> Don't play tricks with slab constructors as bdev structures tends to not
> get reused very much, and this makes the code a lot less error prone.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Acked-by: Tejun Heo <tj@kernel.org>

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 04/45] fs: simplify freeze_bdev/thaw_bdev
  2020-11-24 13:27 ` [dm-devel] [PATCH 04/45] fs: simplify freeze_bdev/thaw_bdev Christoph Hellwig
@ 2020-11-25  6:07   ` Chao Yu
  2020-11-25 12:29   ` Jan Kara
  1 sibling, 0 replies; 92+ messages in thread
From: Chao Yu @ 2020-11-25  6:07 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

On 2020/11/24 21:27, Christoph Hellwig wrote:
> Store the frozen superblock in struct block_device to avoid the awkward
> interface that can return a sb only used a cookie, an ERR_PTR or NULL.
> 
> Signed-off-by: Christoph Hellwig<hch@lst.de>
> ---
>   drivers/md/dm-core.h      |  5 -----
>   drivers/md/dm.c           | 20 ++++++--------------
>   fs/block_dev.c            | 39 ++++++++++++++++-----------------------
>   fs/buffer.c               |  2 +-
>   fs/ext4/ioctl.c           |  2 +-
>   fs/f2fs/file.c            | 14 +++++---------

For f2fs part,

Acked-by: Chao Yu <yuchao0@huawei.com>

Thanks,

>   fs/xfs/xfs_fsops.c        |  7 ++-----
>   include/linux/blk_types.h |  1 +
>   include/linux/blkdev.h    |  4 ++--
>   9 files changed, 34 insertions(+), 60 deletions(-)

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 30/45] block: remove the nr_sects field in struct hd_struct
  2020-11-24 13:27 ` [dm-devel] [PATCH 30/45] block: remove the nr_sects field in struct hd_struct Christoph Hellwig
  2020-11-24 13:34   ` Coly Li
@ 2020-11-25  6:10   ` Chao Yu
  1 sibling, 0 replies; 92+ messages in thread
From: Chao Yu @ 2020-11-25  6:10 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

On 2020/11/24 21:27, Christoph Hellwig wrote:
> Now that the hd_struct always has a block device attached to it, there is
> no need for having two size field that just get out of sync.
> 
> Additional the field in hd_struct did not use proper serializiation,
> possibly allowing for torn writes.  By only using the block_device field
> this problem also gets fixed.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>   block/bio.c                        |  4 +-
>   block/blk-core.c                   |  2 +-
>   block/blk.h                        | 53 ----------------------
>   block/genhd.c                      | 55 +++++++++++-----------
>   block/partitions/core.c            | 17 ++++---
>   drivers/block/loop.c               |  1 -
>   drivers/block/nbd.c                |  2 +-
>   drivers/block/xen-blkback/common.h |  4 +-
>   drivers/md/bcache/super.c          |  2 +-
>   drivers/s390/block/dasd_ioctl.c    |  4 +-
>   drivers/target/target_core_pscsi.c |  7 +--
>   fs/block_dev.c                     | 73 +-----------------------------
>   fs/f2fs/super.c                    |  2 +-

For f2fs part,

Acked-by: Chao Yu <yuchao0@huawei.com>

Thanks,

>   fs/pstore/blk.c                    |  2 +-
>   include/linux/genhd.h              | 29 +++---------
>   kernel/trace/blktrace.c            |  2 +-
>   16 files changed, 60 insertions(+), 199 deletions(-)

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 38/45] block: switch partition lookup to use struct block_device
  2020-11-24 13:27 ` [dm-devel] [PATCH 38/45] block: switch partition lookup to use struct block_device Christoph Hellwig
  2020-11-24 13:32   ` Coly Li
@ 2020-11-25  6:11   ` Chao Yu
  1 sibling, 0 replies; 92+ messages in thread
From: Chao Yu @ 2020-11-25  6:11 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

On 2020/11/24 21:27, Christoph Hellwig wrote:
> Use struct block_device to lookup partitions on a disk.  This removes
> all usage of struct hd_struct from the I/O path, and this allows removing
> the percpu refcount in struct hd_struct.
> 
> Signed-off-by: Christoph Hellwig<hch@lst.de>
> ---
>   block/bio.c                        |  4 +-
>   block/blk-core.c                   | 66 ++++++++++++++----------------
>   block/blk-flush.c                  |  2 +-
>   block/blk-mq.c                     |  9 ++--
>   block/blk-mq.h                     |  7 ++--
>   block/blk.h                        |  4 +-
>   block/genhd.c                      | 56 +++++++++++++------------
>   block/partitions/core.c            |  7 +---
>   drivers/block/drbd/drbd_receiver.c |  2 +-
>   drivers/block/drbd/drbd_worker.c   |  2 +-
>   drivers/block/zram/zram_drv.c      |  2 +-
>   drivers/md/bcache/request.c        |  4 +-
>   drivers/md/dm.c                    |  4 +-
>   drivers/md/md.c                    |  4 +-
>   drivers/nvme/target/admin-cmd.c    | 20 ++++-----
>   fs/ext4/super.c                    | 18 +++-----
>   fs/ext4/sysfs.c                    | 10 +----
>   fs/f2fs/f2fs.h                     |  2 +-
>   fs/f2fs/super.c                    |  6 +--

For f2fs part,

Acked-by: Chao Yu <yuchao0@huawei.com>

Thanks,

>   include/linux/blkdev.h             |  8 ++--
>   include/linux/genhd.h              |  4 +-
>   include/linux/part_stat.h          | 17 ++++----
>   22 files changed, 120 insertions(+), 138 deletions(-)

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 43/45] f2fs: remove a few bd_part checks
  2020-11-24 13:27 ` [dm-devel] [PATCH 43/45] f2fs: remove a few bd_part checks Christoph Hellwig
@ 2020-11-25  6:12   ` Chao Yu
  0 siblings, 0 replies; 92+ messages in thread
From: Chao Yu @ 2020-11-25  6:12 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

On 2020/11/24 21:27, Christoph Hellwig wrote:
> bd_part is never NULL for a block device in use by a file system, so
> remove the checks.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Chao Yu <yuchao0@huawei.com>

Thanks,

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 01/45] blk-cgroup: fix a hd_struct leak in blkcg_fill_root_iostats
  2020-11-24 13:27 ` [dm-devel] [PATCH 01/45] blk-cgroup: fix a hd_struct leak in blkcg_fill_root_iostats Christoph Hellwig
@ 2020-11-25  6:41   ` Hannes Reinecke
  0 siblings, 0 replies; 92+ messages in thread
From: Hannes Reinecke @ 2020-11-25  6:41 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

On 11/24/20 2:27 PM, Christoph Hellwig wrote:
> disk_get_part needs to be paired with a disk_put_part.
> 
> Fixes: ef45fe470e1 ("blk-cgroup: show global disk stats in root cgroup io.stat")
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Reviewed-by: Jan Kara <jack@suse.cz>
> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> Acked-by: Tejun Heo <tj@kernel.org>
> ---
>   block/blk-cgroup.c | 1 +
>   1 file changed, 1 insertion(+)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer


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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 02/45] filemap: consistently use ->f_mapping over ->i_mapping
  2020-11-24 13:27 ` [dm-devel] [PATCH 02/45] filemap: consistently use ->f_mapping over ->i_mapping Christoph Hellwig
  2020-11-24 13:53   ` Matthew Wilcox
@ 2020-11-25  6:41   ` Hannes Reinecke
  2020-11-25 12:16   ` Jan Kara
  2 siblings, 0 replies; 92+ messages in thread
From: Hannes Reinecke @ 2020-11-25  6:41 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

On 11/24/20 2:27 PM, Christoph Hellwig wrote:
> Use file->f_mapping in all remaining places that have a struct file
> available to properly handle the case where inode->i_mapping !=
> file_inode(file)->i_mapping.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   mm/filemap.c | 13 ++++++-------
>   1 file changed, 6 insertions(+), 7 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer


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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 03/45] fs: remove get_super_thawed and get_super_exclusive_thawed
  2020-11-24 13:27 ` [dm-devel] [PATCH 03/45] fs: remove get_super_thawed and get_super_exclusive_thawed Christoph Hellwig
@ 2020-11-25  6:42   ` Hannes Reinecke
  2020-11-25 12:19   ` Jan Kara
  1 sibling, 0 replies; 92+ messages in thread
From: Hannes Reinecke @ 2020-11-25  6:42 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe
  Cc: linux-bcache, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-mm

On 11/24/20 2:27 PM, Christoph Hellwig wrote:
> Just open code the wait in the only caller of both functions.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   fs/internal.h      |  2 ++
>   fs/quota/quota.c   | 31 +++++++++++++++++++++-------
>   fs/super.c         | 51 ++--------------------------------------------
>   include/linux/fs.h |  4 +---
>   4 files changed, 29 insertions(+), 59 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer


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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 02/45] filemap: consistently use ->f_mapping over ->i_mapping
  2020-11-24 13:27 ` [dm-devel] [PATCH 02/45] filemap: consistently use ->f_mapping over ->i_mapping Christoph Hellwig
  2020-11-24 13:53   ` Matthew Wilcox
  2020-11-25  6:41   ` Hannes Reinecke
@ 2020-11-25 12:16   ` Jan Kara
  2 siblings, 0 replies; 92+ messages in thread
From: Jan Kara @ 2020-11-25 12:16 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-bcache, linux-mm

On Tue 24-11-20 14:27:08, Christoph Hellwig wrote:
> Use file->f_mapping in all remaining places that have a struct file
> available to properly handle the case where inode->i_mapping !=
> file_inode(file)->i_mapping.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Looks good to me. You can add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  mm/filemap.c | 13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/mm/filemap.c b/mm/filemap.c
> index d5e7c2029d16b4..4f583489aa3c2a 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -2886,14 +2886,14 @@ EXPORT_SYMBOL(filemap_map_pages);
>  
>  vm_fault_t filemap_page_mkwrite(struct vm_fault *vmf)
>  {
> +	struct address_space *mapping = vmf->vma->vm_file->f_mapping;
>  	struct page *page = vmf->page;
> -	struct inode *inode = file_inode(vmf->vma->vm_file);
>  	vm_fault_t ret = VM_FAULT_LOCKED;
>  
> -	sb_start_pagefault(inode->i_sb);
> +	sb_start_pagefault(mapping->host->i_sb);
>  	file_update_time(vmf->vma->vm_file);
>  	lock_page(page);
> -	if (page->mapping != inode->i_mapping) {
> +	if (page->mapping != mapping) {
>  		unlock_page(page);
>  		ret = VM_FAULT_NOPAGE;
>  		goto out;
> @@ -2906,7 +2906,7 @@ vm_fault_t filemap_page_mkwrite(struct vm_fault *vmf)
>  	set_page_dirty(page);
>  	wait_for_stable_page(page);
>  out:
> -	sb_end_pagefault(inode->i_sb);
> +	sb_end_pagefault(mapping->host->i_sb);
>  	return ret;
>  }
>  
> @@ -3149,10 +3149,9 @@ void dio_warn_stale_pagecache(struct file *filp)
>  {
>  	static DEFINE_RATELIMIT_STATE(_rs, 86400 * HZ, DEFAULT_RATELIMIT_BURST);
>  	char pathname[128];
> -	struct inode *inode = file_inode(filp);
>  	char *path;
>  
> -	errseq_set(&inode->i_mapping->wb_err, -EIO);
> +	errseq_set(&filp->f_mapping->wb_err, -EIO);
>  	if (__ratelimit(&_rs)) {
>  		path = file_path(filp, pathname, sizeof(pathname));
>  		if (IS_ERR(path))
> @@ -3179,7 +3178,7 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
>  
>  	if (iocb->ki_flags & IOCB_NOWAIT) {
>  		/* If there are pages to writeback, return */
> -		if (filemap_range_has_page(inode->i_mapping, pos,
> +		if (filemap_range_has_page(file->f_mapping, pos,
>  					   pos + write_len - 1))
>  			return -EAGAIN;
>  	} else {
> -- 
> 2.29.2
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 03/45] fs: remove get_super_thawed and get_super_exclusive_thawed
  2020-11-24 13:27 ` [dm-devel] [PATCH 03/45] fs: remove get_super_thawed and get_super_exclusive_thawed Christoph Hellwig
  2020-11-25  6:42   ` Hannes Reinecke
@ 2020-11-25 12:19   ` Jan Kara
  1 sibling, 0 replies; 92+ messages in thread
From: Jan Kara @ 2020-11-25 12:19 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-bcache, linux-mm

On Tue 24-11-20 14:27:09, Christoph Hellwig wrote:
> Just open code the wait in the only caller of both functions.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Fine by me. You can add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/internal.h      |  2 ++
>  fs/quota/quota.c   | 31 +++++++++++++++++++++-------
>  fs/super.c         | 51 ++--------------------------------------------
>  include/linux/fs.h |  4 +---
>  4 files changed, 29 insertions(+), 59 deletions(-)
> 
> diff --git a/fs/internal.h b/fs/internal.h
> index a7cd0f64faa4ab..47be21dfeebef5 100644
> --- a/fs/internal.h
> +++ b/fs/internal.h
> @@ -114,7 +114,9 @@ extern struct file *alloc_empty_file_noaccount(int, const struct cred *);
>   */
>  extern int reconfigure_super(struct fs_context *);
>  extern bool trylock_super(struct super_block *sb);
> +struct super_block *__get_super(struct block_device *bdev, bool excl);
>  extern struct super_block *user_get_super(dev_t);
> +void put_super(struct super_block *sb);
>  extern bool mount_capable(struct fs_context *);
>  
>  /*
> diff --git a/fs/quota/quota.c b/fs/quota/quota.c
> index 9af95c7a0bbe3c..f3d32b0d9008f2 100644
> --- a/fs/quota/quota.c
> +++ b/fs/quota/quota.c
> @@ -20,6 +20,7 @@
>  #include <linux/writeback.h>
>  #include <linux/nospec.h>
>  #include "compat.h"
> +#include "../internal.h"
>  
>  static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
>  				     qid_t id)
> @@ -868,6 +869,7 @@ static struct super_block *quotactl_block(const char __user *special, int cmd)
>  	struct block_device *bdev;
>  	struct super_block *sb;
>  	struct filename *tmp = getname(special);
> +	bool excl = false, thawed = false;
>  
>  	if (IS_ERR(tmp))
>  		return ERR_CAST(tmp);
> @@ -875,17 +877,32 @@ static struct super_block *quotactl_block(const char __user *special, int cmd)
>  	putname(tmp);
>  	if (IS_ERR(bdev))
>  		return ERR_CAST(bdev);
> -	if (quotactl_cmd_onoff(cmd))
> -		sb = get_super_exclusive_thawed(bdev);
> -	else if (quotactl_cmd_write(cmd))
> -		sb = get_super_thawed(bdev);
> -	else
> -		sb = get_super(bdev);
> +
> +	if (quotactl_cmd_onoff(cmd)) {
> +		excl = true;
> +		thawed = true;
> +	} else if (quotactl_cmd_write(cmd)) {
> +		thawed = true;
> +	}
> +
> +retry:
> +	sb = __get_super(bdev, excl);
> +	if (thawed && sb && sb->s_writers.frozen != SB_UNFROZEN) {
> +		if (excl)
> +			up_write(&sb->s_umount);
> +		else
> +			up_read(&sb->s_umount);
> +		wait_event(sb->s_writers.wait_unfrozen,
> +			   sb->s_writers.frozen == SB_UNFROZEN);
> +		put_super(sb);
> +		goto retry;
> +	}
> +
>  	bdput(bdev);
>  	if (!sb)
>  		return ERR_PTR(-ENODEV);
> -
>  	return sb;
> +
>  #else
>  	return ERR_PTR(-ENODEV);
>  #endif
> diff --git a/fs/super.c b/fs/super.c
> index 98bb0629ee108e..343e5c1e538d2a 100644
> --- a/fs/super.c
> +++ b/fs/super.c
> @@ -307,7 +307,7 @@ static void __put_super(struct super_block *s)
>   *	Drops a temporary reference, frees superblock if there's no
>   *	references left.
>   */
> -static void put_super(struct super_block *sb)
> +void put_super(struct super_block *sb)
>  {
>  	spin_lock(&sb_lock);
>  	__put_super(sb);
> @@ -740,7 +740,7 @@ void iterate_supers_type(struct file_system_type *type,
>  
>  EXPORT_SYMBOL(iterate_supers_type);
>  
> -static struct super_block *__get_super(struct block_device *bdev, bool excl)
> +struct super_block *__get_super(struct block_device *bdev, bool excl)
>  {
>  	struct super_block *sb;
>  
> @@ -789,53 +789,6 @@ struct super_block *get_super(struct block_device *bdev)
>  }
>  EXPORT_SYMBOL(get_super);
>  
> -static struct super_block *__get_super_thawed(struct block_device *bdev,
> -					      bool excl)
> -{
> -	while (1) {
> -		struct super_block *s = __get_super(bdev, excl);
> -		if (!s || s->s_writers.frozen == SB_UNFROZEN)
> -			return s;
> -		if (!excl)
> -			up_read(&s->s_umount);
> -		else
> -			up_write(&s->s_umount);
> -		wait_event(s->s_writers.wait_unfrozen,
> -			   s->s_writers.frozen == SB_UNFROZEN);
> -		put_super(s);
> -	}
> -}
> -
> -/**
> - *	get_super_thawed - get thawed superblock of a device
> - *	@bdev: device to get the superblock for
> - *
> - *	Scans the superblock list and finds the superblock of the file system
> - *	mounted on the device. The superblock is returned once it is thawed
> - *	(or immediately if it was not frozen). %NULL is returned if no match
> - *	is found.
> - */
> -struct super_block *get_super_thawed(struct block_device *bdev)
> -{
> -	return __get_super_thawed(bdev, false);
> -}
> -EXPORT_SYMBOL(get_super_thawed);
> -
> -/**
> - *	get_super_exclusive_thawed - get thawed superblock of a device
> - *	@bdev: device to get the superblock for
> - *
> - *	Scans the superblock list and finds the superblock of the file system
> - *	mounted on the device. The superblock is returned once it is thawed
> - *	(or immediately if it was not frozen) and s_umount semaphore is held
> - *	in exclusive mode. %NULL is returned if no match is found.
> - */
> -struct super_block *get_super_exclusive_thawed(struct block_device *bdev)
> -{
> -	return __get_super_thawed(bdev, true);
> -}
> -EXPORT_SYMBOL(get_super_exclusive_thawed);
> -
>  /**
>   * get_active_super - get an active reference to the superblock of a device
>   * @bdev: device to get the superblock for
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 8667d0cdc71e76..a61df0dd4f1989 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1409,7 +1409,7 @@ enum {
>  
>  struct sb_writers {
>  	int				frozen;		/* Is sb frozen? */
> -	wait_queue_head_t		wait_unfrozen;	/* for get_super_thawed() */
> +	wait_queue_head_t		wait_unfrozen;	/* wait for thaw */
>  	struct percpu_rw_semaphore	rw_sem[SB_FREEZE_LEVELS];
>  };
>  
> @@ -3132,8 +3132,6 @@ extern struct file_system_type *get_filesystem(struct file_system_type *fs);
>  extern void put_filesystem(struct file_system_type *fs);
>  extern struct file_system_type *get_fs_type(const char *name);
>  extern struct super_block *get_super(struct block_device *);
> -extern struct super_block *get_super_thawed(struct block_device *);
> -extern struct super_block *get_super_exclusive_thawed(struct block_device *bdev);
>  extern struct super_block *get_active_super(struct block_device *bdev);
>  extern void drop_super(struct super_block *sb);
>  extern void drop_super_exclusive(struct super_block *sb);
> -- 
> 2.29.2
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 04/45] fs: simplify freeze_bdev/thaw_bdev
  2020-11-24 13:27 ` [dm-devel] [PATCH 04/45] fs: simplify freeze_bdev/thaw_bdev Christoph Hellwig
  2020-11-25  6:07   ` Chao Yu
@ 2020-11-25 12:29   ` Jan Kara
  2020-11-25 16:22     ` Christoph Hellwig
  1 sibling, 1 reply; 92+ messages in thread
From: Jan Kara @ 2020-11-25 12:29 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-bcache, linux-mm

On Tue 24-11-20 14:27:10, Christoph Hellwig wrote:
> Store the frozen superblock in struct block_device to avoid the awkward
> interface that can return a sb only used a cookie, an ERR_PTR or NULL.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Some comments below...

> diff --git a/fs/block_dev.c b/fs/block_dev.c
> index d8664f5c1ff669..60492620d51866 100644
> --- a/fs/block_dev.c
> +++ b/fs/block_dev.c
> @@ -548,55 +548,47 @@ EXPORT_SYMBOL(fsync_bdev);
>   * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
>   * actually.
>   */
> -struct super_block *freeze_bdev(struct block_device *bdev)
> +int freeze_bdev(struct block_device *bdev)
>  {
>  	struct super_block *sb;
>  	int error = 0;
>  
>  	mutex_lock(&bdev->bd_fsfreeze_mutex);
> -	if (++bdev->bd_fsfreeze_count > 1) {
> -		/*
> -		 * We don't even need to grab a reference - the first call
> -		 * to freeze_bdev grab an active reference and only the last
> -		 * thaw_bdev drops it.
> -		 */
> -		sb = get_super(bdev);
> -		if (sb)
> -			drop_super(sb);
> -		mutex_unlock(&bdev->bd_fsfreeze_mutex);
> -		return sb;
> -	}
> +	if (++bdev->bd_fsfreeze_count > 1)
> +		goto done;
>  
>  	sb = get_active_super(bdev);
>  	if (!sb)
> -		goto out;
> +		goto sync;
>  	if (sb->s_op->freeze_super)
>  		error = sb->s_op->freeze_super(sb);
>  	else
>  		error = freeze_super(sb);
> +	deactivate_super(sb);
> +
>  	if (error) {
> -		deactivate_super(sb);
>  		bdev->bd_fsfreeze_count--;
> -		mutex_unlock(&bdev->bd_fsfreeze_mutex);
> -		return ERR_PTR(error);
> +		goto done;
>  	}
> -	deactivate_super(sb);
> - out:
> +	bdev->bd_fsfreeze_sb = sb;
> +
> +sync:
>  	sync_blockdev(bdev);
> +done:
>  	mutex_unlock(&bdev->bd_fsfreeze_mutex);
> -	return sb;	/* thaw_bdev releases s->s_umount */
> +	return error;	/* thaw_bdev releases s->s_umount */

The comment about thaw_bdev() seems to be stale? At least I don't see what
it's speaking about...

>  }
>  EXPORT_SYMBOL(freeze_bdev);
>  
>  /**
>   * thaw_bdev  -- unlock filesystem
>   * @bdev:	blockdevice to unlock
> - * @sb:		associated superblock
>   *
>   * Unlocks the filesystem and marks it writeable again after freeze_bdev().
>   */
> -int thaw_bdev(struct block_device *bdev, struct super_block *sb)
> +int thaw_bdev(struct block_device *bdev)
>  {
> +	struct super_block *sb;
>  	int error = -EINVAL;
>  
>  	mutex_lock(&bdev->bd_fsfreeze_mutex);
> @@ -607,6 +599,7 @@ int thaw_bdev(struct block_device *bdev, struct super_block *sb)
>  	if (--bdev->bd_fsfreeze_count > 0)
>  		goto out;
>  
> +	sb = bdev->bd_fsfreeze_sb;
>  	if (!sb)
>  		goto out;
>  
> @@ -618,7 +611,7 @@ int thaw_bdev(struct block_device *bdev, struct super_block *sb)
>  		bdev->bd_fsfreeze_count++;
>  out:
>  	mutex_unlock(&bdev->bd_fsfreeze_mutex);
> -	return error;
> +	return 0;

But we now won't return -EINVAL if this gets called e.g. with
bd_fsfreeze_count == 0, right?

									Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 05/45] mtip32xx: remove the call to fsync_bdev on removal
  2020-11-24 13:27 ` [dm-devel] [PATCH 05/45] mtip32xx: remove the call to fsync_bdev on removal Christoph Hellwig
@ 2020-11-25 12:31   ` Jan Kara
  0 siblings, 0 replies; 92+ messages in thread
From: Jan Kara @ 2020-11-25 12:31 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-bcache, linux-mm

On Tue 24-11-20 14:27:11, Christoph Hellwig wrote:
> del_gendisk already calls fsync_bdev for every partition, no need
> to do this twice.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Makes sense to me. You can add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  drivers/block/mtip32xx/mtip32xx.c | 15 ---------------
>  drivers/block/mtip32xx/mtip32xx.h |  2 --
>  2 files changed, 17 deletions(-)
> 
> diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
> index 153e2cdecb4d40..53ac59d19ae530 100644
> --- a/drivers/block/mtip32xx/mtip32xx.c
> +++ b/drivers/block/mtip32xx/mtip32xx.c
> @@ -3687,7 +3687,6 @@ static int mtip_block_initialize(struct driver_data *dd)
>  	/* Enable the block device and add it to /dev */
>  	device_add_disk(&dd->pdev->dev, dd->disk, NULL);
>  
> -	dd->bdev = bdget_disk(dd->disk, 0);
>  	/*
>  	 * Now that the disk is active, initialize any sysfs attributes
>  	 * managed by the protocol layer.
> @@ -3721,9 +3720,6 @@ static int mtip_block_initialize(struct driver_data *dd)
>  	return rv;
>  
>  kthread_run_error:
> -	bdput(dd->bdev);
> -	dd->bdev = NULL;
> -
>  	/* Delete our gendisk. This also removes the device from /dev */
>  	del_gendisk(dd->disk);
>  
> @@ -3804,14 +3800,6 @@ static int mtip_block_remove(struct driver_data *dd)
>  	blk_mq_tagset_busy_iter(&dd->tags, mtip_no_dev_cleanup, dd);
>  	blk_mq_unquiesce_queue(dd->queue);
>  
> -	/*
> -	 * Delete our gendisk structure. This also removes the device
> -	 * from /dev
> -	 */
> -	if (dd->bdev) {
> -		bdput(dd->bdev);
> -		dd->bdev = NULL;
> -	}
>  	if (dd->disk) {
>  		if (test_bit(MTIP_DDF_INIT_DONE_BIT, &dd->dd_flag))
>  			del_gendisk(dd->disk);
> @@ -4206,9 +4194,6 @@ static void mtip_pci_remove(struct pci_dev *pdev)
>  	} while (atomic_read(&dd->irq_workers_active) != 0 &&
>  		time_before(jiffies, to));
>  
> -	if (!dd->sr)
> -		fsync_bdev(dd->bdev);
> -
>  	if (atomic_read(&dd->irq_workers_active) != 0) {
>  		dev_warn(&dd->pdev->dev,
>  			"Completion workers still active!\n");
> diff --git a/drivers/block/mtip32xx/mtip32xx.h b/drivers/block/mtip32xx/mtip32xx.h
> index e22a7f0523bf30..88f4206310e4c8 100644
> --- a/drivers/block/mtip32xx/mtip32xx.h
> +++ b/drivers/block/mtip32xx/mtip32xx.h
> @@ -463,8 +463,6 @@ struct driver_data {
>  
>  	int isr_binding;
>  
> -	struct block_device *bdev;
> -
>  	struct list_head online_list; /* linkage for online list */
>  
>  	struct list_head remove_list; /* linkage for removing list */
> -- 
> 2.29.2
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 06/45] zram: remove the claim mechanism
  2020-11-24 13:27 ` [dm-devel] [PATCH 06/45] zram: remove the claim mechanism Christoph Hellwig
@ 2020-11-25 12:37   ` Jan Kara
  0 siblings, 0 replies; 92+ messages in thread
From: Jan Kara @ 2020-11-25 12:37 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-bcache, linux-mm

On Tue 24-11-20 14:27:12, Christoph Hellwig wrote:
> The zram claim mechanism was added to ensure no new opens come in
> during teardown.  But the proper way to archive that is to call
					  ^^^ achieve

> del_gendisk first, which takes care of all that.  Once del_gendisk
> is called in the right place, the reset side can also be simplified
> as no I/O can be outstanding on a block device that is not open.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Otherwise I didn't find anything obviously wrong with the patch but I don't
feel confident enough with zram to really give you my reviewed-by on this
one.

								Honza

> ---
>  drivers/block/zram/zram_drv.c | 72 ++++++++---------------------------
>  1 file changed, 15 insertions(+), 57 deletions(-)
> 
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index 6d15d51cee2b7e..2e6d75ec1afddb 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -1756,64 +1756,33 @@ static ssize_t disksize_store(struct device *dev,
>  static ssize_t reset_store(struct device *dev,
>  		struct device_attribute *attr, const char *buf, size_t len)
>  {
> -	int ret;
> -	unsigned short do_reset;
> -	struct zram *zram;
> +	struct zram *zram = dev_to_zram(dev);
>  	struct block_device *bdev;
> +	unsigned short do_reset;
> +	int ret = 0;
>  
>  	ret = kstrtou16(buf, 10, &do_reset);
>  	if (ret)
>  		return ret;
> -
>  	if (!do_reset)
>  		return -EINVAL;
>  
> -	zram = dev_to_zram(dev);
>  	bdev = bdget_disk(zram->disk, 0);
>  	if (!bdev)
>  		return -ENOMEM;
>  
>  	mutex_lock(&bdev->bd_mutex);
> -	/* Do not reset an active device or claimed device */
> -	if (bdev->bd_openers || zram->claim) {
> -		mutex_unlock(&bdev->bd_mutex);
> -		bdput(bdev);
> -		return -EBUSY;
> -	}
> -
> -	/* From now on, anyone can't open /dev/zram[0-9] */
> -	zram->claim = true;
> +	if (bdev->bd_openers)
> +		ret = -EBUSY;
> +	else
> +		zram_reset_device(zram);
>  	mutex_unlock(&bdev->bd_mutex);
> -
> -	/* Make sure all the pending I/O are finished */
> -	fsync_bdev(bdev);
> -	zram_reset_device(zram);
>  	bdput(bdev);
>  
> -	mutex_lock(&bdev->bd_mutex);
> -	zram->claim = false;
> -	mutex_unlock(&bdev->bd_mutex);
> -
> -	return len;
> -}
> -
> -static int zram_open(struct block_device *bdev, fmode_t mode)
> -{
> -	int ret = 0;
> -	struct zram *zram;
> -
> -	WARN_ON(!mutex_is_locked(&bdev->bd_mutex));
> -
> -	zram = bdev->bd_disk->private_data;
> -	/* zram was claimed to reset so open request fails */
> -	if (zram->claim)
> -		ret = -EBUSY;
> -
> -	return ret;
> +	return ret ? ret : len;
>  }
>  
>  static const struct block_device_operations zram_devops = {
> -	.open = zram_open,
>  	.submit_bio = zram_submit_bio,
>  	.swap_slot_free_notify = zram_slot_free_notify,
>  	.rw_page = zram_rw_page,
> @@ -1821,7 +1790,6 @@ static const struct block_device_operations zram_devops = {
>  };
>  
>  static const struct block_device_operations zram_wb_devops = {
> -	.open = zram_open,
>  	.submit_bio = zram_submit_bio,
>  	.swap_slot_free_notify = zram_slot_free_notify,
>  	.owner = THIS_MODULE
> @@ -1974,32 +1942,22 @@ static int zram_add(void)
>  
>  static int zram_remove(struct zram *zram)
>  {
> -	struct block_device *bdev;
> -
> -	bdev = bdget_disk(zram->disk, 0);
> -	if (!bdev)
> -		return -ENOMEM;
> +	struct block_device *bdev = bdget_disk(zram->disk, 0);
>  
> -	mutex_lock(&bdev->bd_mutex);
> -	if (bdev->bd_openers || zram->claim) {
> -		mutex_unlock(&bdev->bd_mutex);
> +	if (bdev) {
> +		if (bdev->bd_openers) {
> +			bdput(bdev);
> +			return -EBUSY;
> +		}
>  		bdput(bdev);
> -		return -EBUSY;
>  	}
>  
> -	zram->claim = true;
> -	mutex_unlock(&bdev->bd_mutex);
> -
> +	del_gendisk(zram->disk);
>  	zram_debugfs_unregister(zram);
> -
> -	/* Make sure all the pending I/O are finished */
> -	fsync_bdev(bdev);
>  	zram_reset_device(zram);
> -	bdput(bdev);
>  
>  	pr_info("Removed device: %s\n", zram->disk->disk_name);
>  
> -	del_gendisk(zram->disk);
>  	blk_cleanup_queue(zram->disk->queue);
>  	put_disk(zram->disk);
>  	kfree(zram);
> -- 
> 2.29.2
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 08/45] loop: do not call set_blocksize
  2020-11-24 13:27 ` [dm-devel] [PATCH 08/45] loop: " Christoph Hellwig
@ 2020-11-25 13:37   ` Jan Kara
  0 siblings, 0 replies; 92+ messages in thread
From: Jan Kara @ 2020-11-25 13:37 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-bcache, linux-mm

On Tue 24-11-20 14:27:14, Christoph Hellwig wrote:
> set_blocksize is used by file systems to use their preferred buffer cache
> block size.  Block drivers should not set it.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Looks good to me. You can add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  drivers/block/loop.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index 9a27d4f1c08aac..b42c728620c9e4 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -1164,9 +1164,6 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
>  	size = get_loop_size(lo, file);
>  	loop_set_size(lo, size);
>  
> -	set_blocksize(bdev, S_ISBLK(inode->i_mode) ?
> -		      block_size(inode->i_bdev) : PAGE_SIZE);
> -
>  	lo->lo_state = Lo_bound;
>  	if (part_shift)
>  		lo->lo_flags |= LO_FLAGS_PARTSCAN;
> -- 
> 2.29.2
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 12/45] block: remove a superflous check in blkpg_do_ioctl
  2020-11-24 13:27 ` [dm-devel] [PATCH 12/45] block: remove a superflous check in blkpg_do_ioctl Christoph Hellwig
  2020-11-24 17:37   ` Tejun Heo
@ 2020-11-25 13:39   ` Jan Kara
  1 sibling, 0 replies; 92+ messages in thread
From: Jan Kara @ 2020-11-25 13:39 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, linux-fsdevel, Mike Snitzer,
	Konrad Rzeszutek Wilk, Greg Kroah-Hartman, Jan Kara, Josef Bacik,
	Coly Li, linux-block, Richard Weinberger, dm-devel, linux-mtd,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-bcache, linux-mm

On Tue 24-11-20 14:27:18, Christoph Hellwig wrote:
> sector_t is now always a u64, so this check is not needed.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Looks good. You can add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  block/ioctl.c | 9 ---------
>  1 file changed, 9 deletions(-)
> 
> diff --git a/block/ioctl.c b/block/ioctl.c
> index 6b785181344fe1..0c09bb7a6ff35f 100644
> --- a/block/ioctl.c
> +++ b/block/ioctl.c
> @@ -35,15 +35,6 @@ static int blkpg_do_ioctl(struct block_device *bdev,
>  	start = p.start >> SECTOR_SHIFT;
>  	length = p.length >> SECTOR_SHIFT;
>  
> -	/* check for fit in a hd_struct */
> -	if (sizeof(sector_t) < sizeof(long long)) {
> -		long pstart = start, plength = length;
> -
> -		if (pstart != start || plength != length || pstart < 0 ||
> -		    plength < 0 || p.pno > 65535)
> -			return -EINVAL;
> -	}
> -
>  	switch (op) {
>  	case BLKPG_ADD_PARTITION:
>  		/* check if partition is aligned to blocksize */
> -- 
> 2.29.2
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 04/45] fs: simplify freeze_bdev/thaw_bdev
  2020-11-25 12:29   ` Jan Kara
@ 2020-11-25 16:22     ` Christoph Hellwig
  0 siblings, 0 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-25 16:22 UTC (permalink / raw)
  To: Jan Kara
  Cc: Jens Axboe, linux-fsdevel, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, linux-mm,
	Johannes Thumshirn, Tejun Heo, xen-devel, linux-bcache,
	Christoph Hellwig

On Wed, Nov 25, 2020 at 01:29:53PM +0100, Jan Kara wrote:
> >  	mutex_unlock(&bdev->bd_fsfreeze_mutex);
> > -	return sb;	/* thaw_bdev releases s->s_umount */
> > +	return error;	/* thaw_bdev releases s->s_umount */
> 
> The comment about thaw_bdev() seems to be stale? At least I don't see what
> it's speaking about...

Yes, this comment seems long stale.  I think in the very early days
we held s_umount on frozen file system, which caused all kinds of
problems.

> >  	mutex_unlock(&bdev->bd_fsfreeze_mutex);
> > -	return error;
> > +	return 0;
> 
> But we now won't return -EINVAL if this gets called e.g. with
> bd_fsfreeze_count == 0, right?

Yes.  I had tried to drop the return value as all the freeze_bdev
calls ignored it.  But I had missed the unpaired emergency thaw and put
it back and messed this up..

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 23/45] block: remove i_bdev
  2020-11-24 19:37   ` Tejun Heo
@ 2020-11-25 16:29     ` Christoph Hellwig
  2020-11-25 20:19       ` Tejun Heo
  0 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-25 16:29 UTC (permalink / raw)
  To: Tejun Heo
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, linux-mm,
	Johannes Thumshirn, linux-fsdevel, xen-devel, linux-bcache,
	Christoph Hellwig

On Tue, Nov 24, 2020 at 02:37:05PM -0500, Tejun Heo wrote:
> On Tue, Nov 24, 2020 at 02:27:29PM +0100, Christoph Hellwig wrote:
> > Switch the block device lookup interfaces to directly work with a dev_t
> > so that struct block_device references are only acquired by the
> > blkdev_get variants (and the blk-cgroup special case).  This means that
> > we not don't need an extra reference in the inode and can generally
>      ^
>      now
> > simplify handling of struct block_device to keep the lookups contained
> > in the core block layer code.
> > 
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
> ...
> > @@ -1689,14 +1599,12 @@ static int blkdev_open(struct inode * inode, struct file * filp)
> >  	if ((filp->f_flags & O_ACCMODE) == 3)
> >  		filp->f_mode |= FMODE_WRITE_IOCTL;
> >  
> > -	bdev = bd_acquire(inode);
> > -	if (bdev == NULL)
> > -		return -ENOMEM;
> > -
> > +	bdev = blkdev_get_by_dev(inode->i_rdev, filp->f_mode, filp);
> > +	if (IS_ERR(bdev))
> > +		return PTR_ERR(bdev);
> >  	filp->f_mapping = bdev->bd_inode->i_mapping;
> >  	filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
> > -
> > -	return blkdev_get(bdev, filp->f_mode, filp);
> > +	return 0;
> >  }
> 
> I was wondering whether losing the stale bdev flushing in bd_acquire() would
> cause user-visible behavior changes but can't see how it would given that
> userland has no way of holding onto a specific instance of block inode.
> Maybe it's something worth mentioning in the commit message?

With stale bdev flushing do you mean the call to bd_forget if
i_bdev exists but is unhashed?  It doesn't actually flush anything but
just detaches the old bdev from the inode so that the new one can be
attached.  That problem goes away by definition if we don't attach
the bdev to the inode.

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 25/45] block: reference struct block_device from struct hd_struct
  2020-11-24 21:18   ` Tejun Heo
@ 2020-11-25 16:45     ` Christoph Hellwig
  2020-11-25 20:20       ` Tejun Heo
  0 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-25 16:45 UTC (permalink / raw)
  To: Tejun Heo
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, linux-mm,
	Johannes Thumshirn, linux-fsdevel, xen-devel, linux-bcache,
	Christoph Hellwig

On Tue, Nov 24, 2020 at 04:18:49PM -0500, Tejun Heo wrote:
> Hello,
> 
> Please see lkml.kernel.org/r/X708BTJ5njtbC2z1@mtj.duckdns.org for a few nits
> on the previous version.

Thanks, I've addressed the mapping_set_gfp mask nit and updated the
commit log.  As Jan pointed also pointed out I think we do need the
remove_inode_hash.

> I might be confused but am wondering whether RCU is needed. It's currently
> used to ensure that gendisk is accessible in the blkdev_get path but
> wouldn't it be possible to simply pin gendisk from block_devices? The
> gendisk and hd_structs hold the base refs of the block_devices and in turn
> the block_devices pin the gendisk. When the gendisk gets deleted, it puts
> the base refs of the block devices but stays around while the block devices
> are being accessed.

Yes, that sounds sensible.  I'll take a look.

> Also, would it make sense to separate out lookup_sem removal? I *think* it's
> there to ensure that the same bdev doesn't get associated with old and new
> gendisks at the same time but can't wrap my head around how it works
> exactly. I can see that this may not be needed once the lifetimes of gendisk
> and block_devices are tied together but that may warrant a bit more
> explanation.

Jan added lookup_sem in commit 56c0908c855afbb to prevent a three way
race between del_gendisk and blkdev_open due to the weird bdev vs
gendisk lifetime rules.  None of that can happen with the new lookup
scheme.

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 23/45] block: remove i_bdev
  2020-11-25 16:29     ` Christoph Hellwig
@ 2020-11-25 20:19       ` Tejun Heo
  0 siblings, 0 replies; 92+ messages in thread
From: Tejun Heo @ 2020-11-25 20:19 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

Hello,

On Wed, Nov 25, 2020 at 05:29:26PM +0100, Christoph Hellwig wrote:
> > I was wondering whether losing the stale bdev flushing in bd_acquire() would
> > cause user-visible behavior changes but can't see how it would given that
> > userland has no way of holding onto a specific instance of block inode.
> > Maybe it's something worth mentioning in the commit message?
> 
> With stale bdev flushing do you mean the call to bd_forget if
> i_bdev exists but is unhashed?  It doesn't actually flush anything but

Yeah.

> just detaches the old bdev from the inode so that the new one can be
> attached.  That problem goes away by definition if we don't attach
> the bdev to the inode.

Yeah, I think so. Was just wondering whether the problem actually goes away.

Thanks.

-- 
tejun

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 25/45] block: reference struct block_device from struct hd_struct
  2020-11-25 16:45     ` Christoph Hellwig
@ 2020-11-25 20:20       ` Tejun Heo
  2020-11-26  8:16         ` Christoph Hellwig
  0 siblings, 1 reply; 92+ messages in thread
From: Tejun Heo @ 2020-11-25 20:20 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, Johannes Thumshirn,
	linux-fsdevel, xen-devel, linux-bcache, linux-mm

Hello,

On Wed, Nov 25, 2020 at 05:45:15PM +0100, Christoph Hellwig wrote:
> On Tue, Nov 24, 2020 at 04:18:49PM -0500, Tejun Heo wrote:
> > Hello,
> > 
> > Please see lkml.kernel.org/r/X708BTJ5njtbC2z1@mtj.duckdns.org for a few nits
> > on the previous version.
> 
> Thanks, I've addressed the mapping_set_gfp mask nit and updated the
> commit log.  As Jan pointed also pointed out I think we do need the
> remove_inode_hash.

Agreed. It'd be nice to replace the stale comment.

> > Also, would it make sense to separate out lookup_sem removal? I *think* it's
> > there to ensure that the same bdev doesn't get associated with old and new
> > gendisks at the same time but can't wrap my head around how it works
> > exactly. I can see that this may not be needed once the lifetimes of gendisk
> > and block_devices are tied together but that may warrant a bit more
> > explanation.
> 
> Jan added lookup_sem in commit 56c0908c855afbb to prevent a three way
> race between del_gendisk and blkdev_open due to the weird bdev vs
> gendisk lifetime rules.  None of that can happen with the new lookup
> scheme.

Understood. I think it'd be worthwhile to note that in the commit log.

Thanks.

-- 
tejun

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 25/45] block: reference struct block_device from struct hd_struct
  2020-11-25 20:20       ` Tejun Heo
@ 2020-11-26  8:16         ` Christoph Hellwig
  0 siblings, 0 replies; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-26  8:16 UTC (permalink / raw)
  To: Tejun Heo
  Cc: Jens Axboe, Jan Kara, Mike Snitzer, Konrad Rzeszutek Wilk,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	Richard Weinberger, dm-devel, linux-mtd, linux-mm,
	Johannes Thumshirn, linux-fsdevel, xen-devel, linux-bcache,
	Christoph Hellwig

On Wed, Nov 25, 2020 at 03:20:23PM -0500, Tejun Heo wrote:
> Agreed. It'd be nice to replace the stale comment.

I've updated the comment.

> > Jan added lookup_sem in commit 56c0908c855afbb to prevent a three way
> > race between del_gendisk and blkdev_open due to the weird bdev vs
> > gendisk lifetime rules.  None of that can happen with the new lookup
> > scheme.
> 
> Understood. I think it'd be worthwhile to note that in the commit log.

So after the idea of just holding a disk reference from each bdev did
not work out very well I've reworked this a bit, and lookup_sem stays,
but becomes global to protect the disk lookup (similar to the previous
global bdev_map_lock).

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^ permalink raw reply	[flat|nested] 92+ messages in thread

* Re: [dm-devel] [PATCH 26/45] block: remove ->bd_contains
  2020-11-28 16:14 ` [dm-devel] [PATCH 26/45] block: remove ->bd_contains Christoph Hellwig
@ 2020-11-30  7:37   ` Hannes Reinecke
  0 siblings, 0 replies; 92+ messages in thread
From: Hannes Reinecke @ 2020-11-30  7:37 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe
  Cc: linux-bcache, Jan Kara, Mike Snitzer, linux-mm,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	linux-fsdevel, dm-devel, linux-mtd, Johannes Thumshirn,
	Tejun Heo

On 11/28/20 5:14 PM, Christoph Hellwig wrote:
> Now that each hd_struct has a reference to the corresponding
> block_device, there is no need for the bd_contains pointer.  Add
> a bdev_whole() helper to look up the whole device block_device
> struture instead.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Reviewed-by: Jan Kara <jack@suse.cz>
> Acked-by: Tejun Heo <tj@kernel.org>
> ---
>   drivers/block/loop.c      |  2 +-
>   drivers/scsi/scsicam.c    |  2 +-
>   fs/block_dev.c            | 22 ++++++++--------------
>   include/linux/blk_types.h |  4 +++-
>   4 files changed, 13 insertions(+), 17 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
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hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer


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^ permalink raw reply	[flat|nested] 92+ messages in thread

* [dm-devel] [PATCH 26/45] block: remove ->bd_contains
  2020-11-28 16:14 [dm-devel] merge struct block_device and struct hd_struct v4 Christoph Hellwig
@ 2020-11-28 16:14 ` Christoph Hellwig
  2020-11-30  7:37   ` Hannes Reinecke
  0 siblings, 1 reply; 92+ messages in thread
From: Christoph Hellwig @ 2020-11-28 16:14 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-bcache, Jan Kara, Mike Snitzer, linux-mm,
	Greg Kroah-Hartman, Jan Kara, Josef Bacik, Coly Li, linux-block,
	linux-fsdevel, dm-devel, linux-mtd, Johannes Thumshirn,
	Tejun Heo

Now that each hd_struct has a reference to the corresponding
block_device, there is no need for the bd_contains pointer.  Add
a bdev_whole() helper to look up the whole device block_device
struture instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Tejun Heo <tj@kernel.org>
---
 drivers/block/loop.c      |  2 +-
 drivers/scsi/scsicam.c    |  2 +-
 fs/block_dev.c            | 22 ++++++++--------------
 include/linux/blk_types.h |  4 +++-
 4 files changed, 13 insertions(+), 17 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 26c7aafba7c5f8..c0df88b3300c41 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1088,7 +1088,7 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
 	 * here to avoid changing device under exclusive owner.
 	 */
 	if (!(mode & FMODE_EXCL)) {
-		claimed_bdev = bdev->bd_contains;
+		claimed_bdev = bdev_whole(bdev);
 		error = bd_prepare_to_claim(bdev, claimed_bdev, loop_configure);
 		if (error)
 			goto out_putf;
diff --git a/drivers/scsi/scsicam.c b/drivers/scsi/scsicam.c
index 682cf08ab04153..f1553a453616fd 100644
--- a/drivers/scsi/scsicam.c
+++ b/drivers/scsi/scsicam.c
@@ -32,7 +32,7 @@
  */
 unsigned char *scsi_bios_ptable(struct block_device *dev)
 {
-	struct address_space *mapping = dev->bd_contains->bd_inode->i_mapping;
+	struct address_space *mapping = bdev_whole(dev)->bd_inode->i_mapping;
 	unsigned char *res = NULL;
 	struct page *page;
 
diff --git a/fs/block_dev.c b/fs/block_dev.c
index b350ed3af83bad..94baee369d26e5 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -119,7 +119,7 @@ int truncate_bdev_range(struct block_device *bdev, fmode_t mode,
 	 * under live filesystem.
 	 */
 	if (!(mode & FMODE_EXCL)) {
-		claimed_bdev = bdev->bd_contains;
+		claimed_bdev = bdev_whole(bdev);
 		err = bd_prepare_to_claim(bdev, claimed_bdev,
 					  truncate_bdev_range);
 		if (err)
@@ -880,7 +880,6 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
 	spin_lock_init(&bdev->bd_size_lock);
 	bdev->bd_disk = disk;
 	bdev->bd_partno = partno;
-	bdev->bd_contains = NULL;
 	bdev->bd_super = NULL;
 	bdev->bd_inode = inode;
 	bdev->bd_part_count = 0;
@@ -1347,9 +1346,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode)
 	int ret;
 
 	if (!bdev->bd_openers) {
-		bdev->bd_contains = bdev;
-
-		if (!bdev->bd_partno) {
+		if (!bdev_is_partition(bdev)) {
 			ret = -ENXIO;
 			bdev->bd_part = disk_get_part(disk, 0);
 			if (!bdev->bd_part)
@@ -1389,7 +1386,6 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode)
 			whole->bd_part_count++;
 			mutex_unlock(&whole->bd_mutex);
 
-			bdev->bd_contains = whole;
 			bdev->bd_part = disk_get_part(disk, bdev->bd_partno);
 			if (!(disk->flags & GENHD_FL_UP) ||
 			    !bdev->bd_part || !bdev->bd_part->nr_sects) {
@@ -1405,7 +1401,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode)
 		if (bdev->bd_bdi == &noop_backing_dev_info)
 			bdev->bd_bdi = bdi_get(disk->queue->backing_dev_info);
 	} else {
-		if (bdev->bd_contains == bdev) {
+		if (!bdev_is_partition(bdev)) {
 			ret = 0;
 			if (bdev->bd_disk->fops->open)
 				ret = bdev->bd_disk->fops->open(bdev, mode);
@@ -1423,7 +1419,6 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode)
  out_clear:
 	disk_put_part(bdev->bd_part);
 	bdev->bd_part = NULL;
-	bdev->bd_contains = NULL;
 	return ret;
 }
 
@@ -1670,8 +1665,7 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
 		disk_put_part(bdev->bd_part);
 		bdev->bd_part = NULL;
 		if (bdev_is_partition(bdev))
-			victim = bdev->bd_contains;
-		bdev->bd_contains = NULL;
+			victim = bdev_whole(bdev);
 	} else {
 		if (!bdev_is_partition(bdev) && disk->fops->release)
 			disk->fops->release(disk, mode);
@@ -1690,6 +1684,7 @@ void blkdev_put(struct block_device *bdev, fmode_t mode)
 	mutex_lock(&bdev->bd_mutex);
 
 	if (mode & FMODE_EXCL) {
+		struct block_device *whole = bdev_whole(bdev);
 		bool bdev_free;
 
 		/*
@@ -1700,13 +1695,12 @@ void blkdev_put(struct block_device *bdev, fmode_t mode)
 		spin_lock(&bdev_lock);
 
 		WARN_ON_ONCE(--bdev->bd_holders < 0);
-		WARN_ON_ONCE(--bdev->bd_contains->bd_holders < 0);
+		WARN_ON_ONCE(--whole->bd_holders < 0);
 
-		/* bd_contains might point to self, check in a separate step */
 		if ((bdev_free = !bdev->bd_holders))
 			bdev->bd_holder = NULL;
-		if (!bdev->bd_contains->bd_holders)
-			bdev->bd_contains->bd_holder = NULL;
+		if (!whole->bd_holders)
+			whole->bd_holder = NULL;
 
 		spin_unlock(&bdev_lock);
 
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 9698f459cc65c9..2e0a9bd9688d28 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -32,7 +32,6 @@ struct block_device {
 #ifdef CONFIG_SYSFS
 	struct list_head	bd_holder_disks;
 #endif
-	struct block_device *	bd_contains;
 	u8			bd_partno;
 	struct hd_struct *	bd_part;
 	/* number of times partitions within this device have been opened. */
@@ -49,6 +48,9 @@ struct block_device {
 	struct super_block	*bd_fsfreeze_sb;
 } __randomize_layout;
 
+#define bdev_whole(_bdev) \
+	((_bdev)->bd_disk->part0.bdev)
+
 #define bdev_kobj(_bdev) \
 	(&part_to_dev((_bdev)->bd_part)->kobj)
 
-- 
2.29.2

--
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^ permalink raw reply	[flat|nested] 92+ messages in thread

end of thread, back to index

Thread overview: 92+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-11-24 13:27 [dm-devel] merge struct block_device and struct hd_struct v2 Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 01/45] blk-cgroup: fix a hd_struct leak in blkcg_fill_root_iostats Christoph Hellwig
2020-11-25  6:41   ` Hannes Reinecke
2020-11-24 13:27 ` [dm-devel] [PATCH 02/45] filemap: consistently use ->f_mapping over ->i_mapping Christoph Hellwig
2020-11-24 13:53   ` Matthew Wilcox
2020-11-25  6:41   ` Hannes Reinecke
2020-11-25 12:16   ` Jan Kara
2020-11-24 13:27 ` [dm-devel] [PATCH 03/45] fs: remove get_super_thawed and get_super_exclusive_thawed Christoph Hellwig
2020-11-25  6:42   ` Hannes Reinecke
2020-11-25 12:19   ` Jan Kara
2020-11-24 13:27 ` [dm-devel] [PATCH 04/45] fs: simplify freeze_bdev/thaw_bdev Christoph Hellwig
2020-11-25  6:07   ` Chao Yu
2020-11-25 12:29   ` Jan Kara
2020-11-25 16:22     ` Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 05/45] mtip32xx: remove the call to fsync_bdev on removal Christoph Hellwig
2020-11-25 12:31   ` Jan Kara
2020-11-24 13:27 ` [dm-devel] [PATCH 06/45] zram: remove the claim mechanism Christoph Hellwig
2020-11-25 12:37   ` Jan Kara
2020-11-24 13:27 ` [dm-devel] [PATCH 07/45] zram: do not call set_blocksize Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 08/45] loop: " Christoph Hellwig
2020-11-25 13:37   ` Jan Kara
2020-11-24 13:27 ` [dm-devel] [PATCH 09/45] dm: simplify flush_bio initialization in __send_empty_flush Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 10/45] dm: remove the block_device reference in struct mapped_device Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 11/45] block: remove a duplicate __disk_get_part prototype Christoph Hellwig
2020-11-24 17:36   ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 12/45] block: remove a superflous check in blkpg_do_ioctl Christoph Hellwig
2020-11-24 17:37   ` Tejun Heo
2020-11-25 13:39   ` Jan Kara
2020-11-24 13:27 ` [dm-devel] [PATCH 13/45] block: add a bdev_kobj helper Christoph Hellwig
2020-11-24 13:41   ` Coly Li
2020-11-24 17:37   ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 14/45] block: use disk_part_iter_exit in disk_part_iter_next Christoph Hellwig
2020-11-24 17:37   ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 15/45] block: use put_device in put_disk Christoph Hellwig
2020-11-24 17:37   ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 16/45] block: change the hash used for looking up block devices Christoph Hellwig
2020-11-24 17:38   ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 17/45] init: refactor name_to_dev_t Christoph Hellwig
2020-11-24 17:38   ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 18/45] init: refactor devt_from_partuuid Christoph Hellwig
2020-11-24 17:38   ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 19/45] init: cleanup match_dev_by_uuid and match_dev_by_label Christoph Hellwig
2020-11-24 17:39   ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 20/45] block: refactor __blkdev_put Christoph Hellwig
2020-11-24 17:41   ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 21/45] block: refactor blkdev_get Christoph Hellwig
2020-11-24 18:03   ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 22/45] block: opencode devcgroup_inode_permission Christoph Hellwig
2020-11-24 18:05   ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 23/45] block: remove i_bdev Christoph Hellwig
2020-11-24 13:38   ` Coly Li
2020-11-24 19:37   ` Tejun Heo
2020-11-25 16:29     ` Christoph Hellwig
2020-11-25 20:19       ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 24/45] blk-cgroup: stop abusing get_gendisk Christoph Hellwig
2020-11-24 19:46   ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 25/45] block: reference struct block_device from struct hd_struct Christoph Hellwig
2020-11-24 21:18   ` Tejun Heo
2020-11-25 16:45     ` Christoph Hellwig
2020-11-25 20:20       ` Tejun Heo
2020-11-26  8:16         ` Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 26/45] block: remove ->bd_contains Christoph Hellwig
2020-11-24 21:19   ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 27/45] block: simplify the block device claiming interface Christoph Hellwig
2020-11-24 21:19   ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 28/45] block: simplify part_to_disk Christoph Hellwig
2020-11-24 21:20   ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 29/45] block: initialize struct block_device in bdev_alloc Christoph Hellwig
2020-11-24 21:20   ` Tejun Heo
2020-11-24 13:27 ` [dm-devel] [PATCH 30/45] block: remove the nr_sects field in struct hd_struct Christoph Hellwig
2020-11-24 13:34   ` Coly Li
2020-11-25  6:10   ` Chao Yu
2020-11-24 13:27 ` [dm-devel] [PATCH 31/45] block: move disk stat accounting to struct block_device Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 32/45] block: move the start_sect field " Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 33/45] block: move the partition_meta_info " Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 34/45] block: move holder_dir " Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 35/45] block: move make_it_fail " Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 36/45] block: move the policy field " Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 37/45] block: allocate struct hd_struct as part of struct bdev_inode Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 38/45] block: switch partition lookup to use struct block_device Christoph Hellwig
2020-11-24 13:32   ` Coly Li
2020-11-25  6:11   ` Chao Yu
2020-11-24 13:27 ` [dm-devel] [PATCH 39/45] block: remove the partno field from struct hd_struct Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 40/45] block: pass a block_device to blk_alloc_devt Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 41/45] block: pass a block_device to invalidate_partition Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 42/45] block: switch disk_part_iter_* to use a struct block_device Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 43/45] f2fs: remove a few bd_part checks Christoph Hellwig
2020-11-25  6:12   ` Chao Yu
2020-11-24 13:27 ` [dm-devel] [PATCH 44/45] block: merge struct block_device and struct hd_struct Christoph Hellwig
2020-11-24 13:27 ` [dm-devel] [PATCH 45/45] block: stop using bdget_disk for partition 0 Christoph Hellwig
2020-11-28 16:14 [dm-devel] merge struct block_device and struct hd_struct v4 Christoph Hellwig
2020-11-28 16:14 ` [dm-devel] [PATCH 26/45] block: remove ->bd_contains Christoph Hellwig
2020-11-30  7:37   ` Hannes Reinecke

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