remove blkdev_get as a public API v2

remove blkdev_get as a public API v2

[Christoph Hellwig]

Hi Jens,

this series removes blkdev_get as a public API, leaving it as just an
implementation detail of blkdev_get_by_path and blkdev_get_by_dev.  The
reason for that is that blkdev_get is a very confusing API that requires
a struct block_device to be fed in, but then actually consumes the
reference.  And it turns out just using the two above mentioned APIs
actually significantly simplifies the code as well.

Changes since v1:
 - fix a mismerged that left a stray bdget_disk around
 - factour the partition scan at registration time code into a new
   helper.

Diffstat:
 block/genhd.c                   |   35 ++++++---------
 block/ioctl.c                   |   13 ++---
 drivers/block/nbd.c             |    8 +--
 drivers/block/pktcdvd.c         |   92 +++++-----------------------------------
 drivers/block/zram/zram_drv.c   |    7 +--
 drivers/char/raw.c              |   51 ++++++++--------------
 drivers/ide/ide-gd.c            |    2 
 drivers/s390/block/dasd_genhd.c |   15 +-----
 fs/block_dev.c                  |   12 ++---
 fs/ocfs2/cluster/heartbeat.c    |   28 ++++--------
 include/linux/blk_types.h       |    4 -
 include/linux/blkdev.h          |    1 
 include/linux/genhd.h           |    2 
 include/linux/suspend.h         |    4 -
 include/linux/swap.h            |    3 -
 kernel/power/swap.c             |   21 +++------
 kernel/power/user.c             |   26 +++--------
 mm/swapfile.c                   |   45 ++++++++++---------
 18 files changed, 130 insertions(+), 239 deletions(-)

[PATCH 01/14] block: move the NEED_PART_SCAN flag to struct gendisk

[Christoph Hellwig]

We can only scan for partitions on the whole disk, so move the flag
from struct block_device to struct gendisk.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c             | 4 ++--
 drivers/block/nbd.c       | 8 ++++----
 drivers/ide/ide-gd.c      | 2 +-
 fs/block_dev.c            | 7 +++----
 include/linux/blk_types.h | 4 +---
 include/linux/genhd.h     | 2 ++
 6 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 9d060e79eb31d8..7b56203c90a303 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -731,7 +731,7 @@ static void register_disk(struct device *parent, struct gendisk *disk,
 	if (!bdev)
 		goto exit;
 
-	set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
+	set_bit(GD_NEED_PART_SCAN, &disk->state);
 	err = blkdev_get(bdev, FMODE_READ, NULL);
 	if (err < 0)
 		goto exit;
@@ -2112,7 +2112,7 @@ bool bdev_check_media_change(struct block_device *bdev)
 	if (__invalidate_device(bdev, true))
 		pr_warn("VFS: busy inodes on changed media %s\n",
 			bdev->bd_disk->disk_name);
-	set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
+	set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
 	return true;
 }
 EXPORT_SYMBOL(bdev_check_media_change);
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 15eed210feeff4..2dca0aab0a9a25 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -315,7 +315,7 @@ static void nbd_size_update(struct nbd_device *nbd)
 			bd_set_nr_sectors(bdev, nr_sectors);
 			set_blocksize(bdev, config->blksize);
 		} else
-			set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
+			set_bit(GD_NEED_PART_SCAN, &nbd->disk->state);
 		bdput(bdev);
 	}
 	kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
@@ -1322,7 +1322,7 @@ static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *b
 		return ret;
 
 	if (max_part)
-		set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
+		set_bit(GD_NEED_PART_SCAN, &nbd->disk->state);
 	mutex_unlock(&nbd->config_lock);
 	ret = wait_event_interruptible(config->recv_wq,
 					 atomic_read(&config->recv_threads) == 0);
@@ -1500,9 +1500,9 @@ static int nbd_open(struct block_device *bdev, fmode_t mode)
 		refcount_set(&nbd->config_refs, 1);
 		refcount_inc(&nbd->refs);
 		mutex_unlock(&nbd->config_lock);
-		set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
+		set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
 	} else if (nbd_disconnected(nbd->config)) {
-		set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
+		set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
 	}
 out:
 	mutex_unlock(&nbd_index_mutex);
diff --git a/drivers/ide/ide-gd.c b/drivers/ide/ide-gd.c
index 661e2aa9c96784..e2b6c82586ce8b 100644
--- a/drivers/ide/ide-gd.c
+++ b/drivers/ide/ide-gd.c
@@ -230,7 +230,7 @@ static int ide_gd_open(struct block_device *bdev, fmode_t mode)
 				bdev->bd_disk->disk_name);
 		drive->disk_ops->get_capacity(drive);
 		set_capacity(disk, ide_gd_capacity(drive));
-		set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
+		set_bit(GD_NEED_PART_SCAN, &disk->state);
 	} else if (drive->dev_flags & IDE_DFLAG_FORMAT_IN_PROGRESS) {
 		ret = -EBUSY;
 		goto out_put_idkp;
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 0b34955b9e360f..1a9325f4315769 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -910,7 +910,6 @@ struct block_device *bdget(dev_t dev)
 		bdev->bd_super = NULL;
 		bdev->bd_inode = inode;
 		bdev->bd_part_count = 0;
-		bdev->bd_flags = 0;
 		inode->i_mode = S_IFBLK;
 		inode->i_rdev = dev;
 		inode->i_bdev = bdev;
@@ -1385,7 +1384,7 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 
 	lockdep_assert_held(&bdev->bd_mutex);
 
-	clear_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
+	clear_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
 
 rescan:
 	ret = blk_drop_partitions(bdev);
@@ -1509,7 +1508,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
 			 * The latter is necessary to prevent ghost
 			 * partitions on a removed medium.
 			 */
-			if (test_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags) &&
+			if (test_bit(GD_NEED_PART_SCAN, &disk->state) &&
 			    (!ret || ret == -ENOMEDIUM))
 				bdev_disk_changed(bdev, ret == -ENOMEDIUM);
 
@@ -1539,7 +1538,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
 			if (bdev->bd_disk->fops->open)
 				ret = bdev->bd_disk->fops->open(bdev, mode);
 			/* the same as first opener case, read comment there */
-			if (test_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags) &&
+			if (test_bit(GD_NEED_PART_SCAN, &disk->state) &&
 			    (!ret || ret == -ENOMEDIUM))
 				bdev_disk_changed(bdev, ret == -ENOMEDIUM);
 			if (ret)
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 6ffa783e16335e..eb20e28184ab19 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -19,8 +19,6 @@ struct cgroup_subsys_state;
 typedef void (bio_end_io_t) (struct bio *);
 struct bio_crypt_ctx;
 
-#define BDEV_NEED_PART_SCAN		0
-
 struct block_device {
 	dev_t			bd_dev;
 	int			bd_openers;
@@ -39,7 +37,7 @@ struct block_device {
 	struct hd_struct *	bd_part;
 	/* number of times partitions within this device have been opened. */
 	unsigned		bd_part_count;
-	unsigned long		bd_flags;
+
 	spinlock_t		bd_size_lock; /* for bd_inode->i_size updates */
 	struct gendisk *	bd_disk;
 	struct backing_dev_info *bd_bdi;
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 1c97cf84f011a7..38f23d75701379 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -191,6 +191,8 @@ struct gendisk {
 	void *private_data;
 
 	int flags;
+	unsigned long state;
+#define GD_NEED_PART_SCAN		0
 	struct rw_semaphore lookup_sem;
 	struct kobject *slave_dir;
 
-- 
2.28.0

[PATCH 02/14] block: cleanup partition scanning in register_disk

[Christoph Hellwig]

Use blkdev_get_by_dev instead of open coding it using bdget_disk +
blkdev_get, and split the code to read the partition table into a
separate helper to make it a little more obvious.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c | 33 ++++++++++++++-------------------
 1 file changed, 14 insertions(+), 19 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 7b56203c90a303..05fb27cbb66784 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -673,11 +673,23 @@ static int exact_lock(dev_t devt, void *data)
 	return 0;
 }
 
+static void disk_scan_partitions(struct gendisk *disk)
+{
+	struct block_device *bdev;
+
+	if (!get_capacity(disk) || !disk_part_scan_enabled(disk))
+		return;
+
+	set_bit(GD_NEED_PART_SCAN, &disk->state);
+	bdev = blkdev_get_by_dev(disk_devt(disk), FMODE_READ, NULL);
+	if (!IS_ERR(bdev))
+		blkdev_put(bdev, FMODE_READ);
+}
+
 static void register_disk(struct device *parent, struct gendisk *disk,
 			  const struct attribute_group **groups)
 {
 	struct device *ddev = disk_to_dev(disk);
-	struct block_device *bdev;
 	struct disk_part_iter piter;
 	struct hd_struct *part;
 	int err;
@@ -719,25 +731,8 @@ static void register_disk(struct device *parent, struct gendisk *disk,
 		return;
 	}
 
-	/* No minors to use for partitions */
-	if (!disk_part_scan_enabled(disk))
-		goto exit;
-
-	/* No such device (e.g., media were just removed) */
-	if (!get_capacity(disk))
-		goto exit;
-
-	bdev = bdget_disk(disk, 0);
-	if (!bdev)
-		goto exit;
-
-	set_bit(GD_NEED_PART_SCAN, &disk->state);
-	err = blkdev_get(bdev, FMODE_READ, NULL);
-	if (err < 0)
-		goto exit;
-	blkdev_put(bdev, FMODE_READ);
+	disk_scan_partitions(disk);
 
-exit:
 	/* announce disk after possible partitions are created */
 	dev_set_uevent_suppress(ddev, 0);
 	kobject_uevent(&ddev->kobj, KOBJ_ADD);
-- 
2.28.0

[PATCH 03/14] block: cleanup blkdev_bszset

[Christoph Hellwig]

Use blkdev_get_by_dev instead of bdgrab + blkdev_get.

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

diff --git a/block/ioctl.c b/block/ioctl.c
index ae74d0409afab9..06262c28f0c6c1 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -478,15 +478,14 @@ static int blkdev_bszset(struct block_device *bdev, fmode_t mode,
 	if (get_user(n, argp))
 		return -EFAULT;
 
-	if (!(mode & FMODE_EXCL)) {
-		bdgrab(bdev);
-		if (blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
-			return -EBUSY;
-	}
+	if (mode & FMODE_EXCL)
+		return set_blocksize(bdev, n);
 
+	if (IS_ERR(blkdev_get_by_dev(bdev->bd_dev, mode | FMODE_EXCL, &bdev)))
+		return -EBUSY;
 	ret = set_blocksize(bdev, n);
-	if (!(mode & FMODE_EXCL))
-		blkdev_put(bdev, mode | FMODE_EXCL);
+	blkdev_put(bdev, mode | FMODE_EXCL);
+
 	return ret;
 }
 
-- 
2.28.0

[PATCH 04/14] pktcdvd: remove the if 0'ed pkt_start_recovery function

[Christoph Hellwig]

Remove code which has been dead since the initial commit.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/block/pktcdvd.c | 67 ++---------------------------------------
 1 file changed, 2 insertions(+), 65 deletions(-)

diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 17f2e6ff122314..bc870a5f15f77b 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -1082,65 +1082,6 @@ static void pkt_put_packet_data(struct pktcdvd_device *pd, struct packet_data *p
 	}
 }
 
-/*
- * recover a failed write, query for relocation if possible
- *
- * returns 1 if recovery is possible, or 0 if not
- *
- */
-static int pkt_start_recovery(struct packet_data *pkt)
-{
-	/*
-	 * FIXME. We need help from the file system to implement
-	 * recovery handling.
-	 */
-	return 0;
-#if 0
-	struct request *rq = pkt->rq;
-	struct pktcdvd_device *pd = rq->rq_disk->private_data;
-	struct block_device *pkt_bdev;
-	struct super_block *sb = NULL;
-	unsigned long old_block, new_block;
-	sector_t new_sector;
-
-	pkt_bdev = bdget(kdev_t_to_nr(pd->pkt_dev));
-	if (pkt_bdev) {
-		sb = get_super(pkt_bdev);
-		bdput(pkt_bdev);
-	}
-
-	if (!sb)
-		return 0;
-
-	if (!sb->s_op->relocate_blocks)
-		goto out;
-
-	old_block = pkt->sector / (CD_FRAMESIZE >> 9);
-	if (sb->s_op->relocate_blocks(sb, old_block, &new_block))
-		goto out;
-
-	new_sector = new_block * (CD_FRAMESIZE >> 9);
-	pkt->sector = new_sector;
-
-	bio_reset(pkt->bio);
-	bio_set_dev(pkt->bio, pd->bdev);
-	bio_set_op_attrs(pkt->bio, REQ_OP_WRITE, 0);
-	pkt->bio->bi_iter.bi_sector = new_sector;
-	pkt->bio->bi_iter.bi_size = pkt->frames * CD_FRAMESIZE;
-	pkt->bio->bi_vcnt = pkt->frames;
-
-	pkt->bio->bi_end_io = pkt_end_io_packet_write;
-	pkt->bio->bi_private = pkt;
-
-	drop_super(sb);
-	return 1;
-
-out:
-	drop_super(sb);
-	return 0;
-#endif
-}
-
 static inline void pkt_set_state(struct packet_data *pkt, enum packet_data_state state)
 {
 #if PACKET_DEBUG > 1
@@ -1357,12 +1298,8 @@ static void pkt_run_state_machine(struct pktcdvd_device *pd, struct packet_data
 			break;
 
 		case PACKET_RECOVERY_STATE:
-			if (pkt_start_recovery(pkt)) {
-				pkt_start_write(pd, pkt);
-			} else {
-				pkt_dbg(2, pd, "No recovery possible\n");
-				pkt_set_state(pkt, PACKET_FINISHED_STATE);
-			}
+			pkt_dbg(2, pd, "No recovery possible\n");
+			pkt_set_state(pkt, PACKET_FINISHED_STATE);
 			break;
 
 		case PACKET_FINISHED_STATE:
-- 
2.28.0

[PATCH 05/14] pktcdvd: use blkdev_get_by_dev instead of open coding it

[Christoph Hellwig]

Replace bdget + blkdev_get by blkdev_get_by_dev.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/block/pktcdvd.c | 25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index bc870a5f15f77b..467dbd06b7cdb1 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -2110,16 +2110,18 @@ static int pkt_open_dev(struct pktcdvd_device *pd, fmode_t write)
 	int ret;
 	long lba;
 	struct request_queue *q;
+	struct block_device *bdev;
 
 	/*
 	 * We need to re-open the cdrom device without O_NONBLOCK to be able
 	 * to read/write from/to it. It is already opened in O_NONBLOCK mode
-	 * so bdget() can't fail.
+	 * so open should not fail.
 	 */
-	bdget(pd->bdev->bd_dev);
-	ret = blkdev_get(pd->bdev, FMODE_READ | FMODE_EXCL, pd);
-	if (ret)
+	bdev = blkdev_get_by_dev(pd->bdev->bd_dev, FMODE_READ | FMODE_EXCL, pd);
+	if (IS_ERR(bdev)) {
+		ret = PTR_ERR(bdev);
 		goto out;
+	}
 
 	ret = pkt_get_last_written(pd, &lba);
 	if (ret) {
@@ -2163,7 +2165,7 @@ static int pkt_open_dev(struct pktcdvd_device *pd, fmode_t write)
 	return 0;
 
 out_putdev:
-	blkdev_put(pd->bdev, FMODE_READ | FMODE_EXCL);
+	blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
 out:
 	return ret;
 }
@@ -2500,7 +2502,6 @@ static int pkt_seq_show(struct seq_file *m, void *p)
 static int pkt_new_dev(struct pktcdvd_device *pd, dev_t dev)
 {
 	int i;
-	int ret = 0;
 	char b[BDEVNAME_SIZE];
 	struct block_device *bdev;
 
@@ -2523,12 +2524,9 @@ static int pkt_new_dev(struct pktcdvd_device *pd, dev_t dev)
 		}
 	}
 
-	bdev = bdget(dev);
-	if (!bdev)
-		return -ENOMEM;
-	ret = blkdev_get(bdev, FMODE_READ | FMODE_NDELAY, NULL);
-	if (ret)
-		return ret;
+	bdev = blkdev_get_by_dev(dev, FMODE_READ | FMODE_NDELAY, NULL);
+	if (IS_ERR(bdev))
+		return PTR_ERR(bdev);
 	if (!blk_queue_scsi_passthrough(bdev_get_queue(bdev))) {
 		blkdev_put(bdev, FMODE_READ | FMODE_NDELAY);
 		return -EINVAL;
@@ -2546,7 +2544,6 @@ static int pkt_new_dev(struct pktcdvd_device *pd, dev_t dev)
 	pd->cdrw.thread = kthread_run(kcdrwd, pd, "%s", pd->name);
 	if (IS_ERR(pd->cdrw.thread)) {
 		pkt_err(pd, "can't start kernel thread\n");
-		ret = -ENOMEM;
 		goto out_mem;
 	}
 
@@ -2558,7 +2555,7 @@ static int pkt_new_dev(struct pktcdvd_device *pd, dev_t dev)
 	blkdev_put(bdev, FMODE_READ | FMODE_NDELAY);
 	/* This is safe: open() is still holding a reference. */
 	module_put(THIS_MODULE);
-	return ret;
+	return -ENOMEM;
 }
 
 static int pkt_ioctl(struct block_device *bdev, fmode_t mode, unsigned int cmd, unsigned long arg)
-- 
2.28.0

[PATCH 06/14] zram: cleanup backing_dev_store

[Christoph Hellwig]

Use blkdev_get_by_dev instead of bdgrab + blkdev_get.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/block/zram/zram_drv.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index a356275605b104..91ccfe444525b4 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -491,9 +491,10 @@ static ssize_t backing_dev_store(struct device *dev,
 		goto out;
 	}
 
-	bdev = bdgrab(I_BDEV(inode));
-	err = blkdev_get(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL, zram);
-	if (err < 0) {
+	bdev = blkdev_get_by_dev(inode->i_rdev,
+			FMODE_READ | FMODE_WRITE | FMODE_EXCL, zram);
+	if (IS_ERR(bdev)) {
+		err = PTR_ERR(bdev);
 		bdev = NULL;
 		goto out;
 	}
-- 
2.28.0

[PATCH 07/14] raw: don't keep unopened block device around

[Christoph Hellwig]

Turn binding into a normal dev_t as the struct block device doesn't
buy us anything and use blkdev_open_by_dev to actually open it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/char/raw.c | 51 +++++++++++++++++-----------------------------
 1 file changed, 19 insertions(+), 32 deletions(-)

diff --git a/drivers/char/raw.c b/drivers/char/raw.c
index ccf5bd528642da..5d52a1f4738c76 100644
--- a/drivers/char/raw.c
+++ b/drivers/char/raw.c
@@ -28,7 +28,8 @@
 #include <linux/uaccess.h>
 
 struct raw_device_data {
-	struct block_device *binding;
+	dev_t binding;
+	struct block_device *bdev;
 	int inuse;
 };
 
@@ -73,14 +74,15 @@ static int raw_open(struct inode *inode, struct file *filp)
 	/*
 	 * All we need to do on open is check that the device is bound.
 	 */
-	bdev = raw_devices[minor].binding;
 	err = -ENODEV;
-	if (!bdev)
+	if (!raw_devices[minor].binding)
 		goto out;
-	bdgrab(bdev);
-	err = blkdev_get(bdev, filp->f_mode | FMODE_EXCL, raw_open);
-	if (err)
+	bdev = blkdev_get_by_dev(raw_devices[minor].binding,
+				 filp->f_mode | FMODE_EXCL, raw_open);
+	if (IS_ERR(bdev)) {
+		err = PTR_ERR(bdev);
 		goto out;
+	}
 	err = set_blocksize(bdev, bdev_logical_block_size(bdev));
 	if (err)
 		goto out1;
@@ -90,6 +92,7 @@ static int raw_open(struct inode *inode, struct file *filp)
 		file_inode(filp)->i_mapping =
 			bdev->bd_inode->i_mapping;
 	filp->private_data = bdev;
+	raw_devices[minor].bdev = bdev;
 	mutex_unlock(&raw_mutex);
 	return 0;
 
@@ -110,7 +113,7 @@ static int raw_release(struct inode *inode, struct file *filp)
 	struct block_device *bdev;
 
 	mutex_lock(&raw_mutex);
-	bdev = raw_devices[minor].binding;
+	bdev = raw_devices[minor].bdev;
 	if (--raw_devices[minor].inuse == 0)
 		/* Here  inode->i_mapping == bdev->bd_inode->i_mapping  */
 		inode->i_mapping = &inode->i_data;
@@ -133,6 +136,7 @@ raw_ioctl(struct file *filp, unsigned int command, unsigned long arg)
 static int bind_set(int number, u64 major, u64 minor)
 {
 	dev_t dev = MKDEV(major, minor);
+	dev_t raw = MKDEV(RAW_MAJOR, number);
 	struct raw_device_data *rawdev;
 	int err = 0;
 
@@ -166,25 +170,17 @@ static int bind_set(int number, u64 major, u64 minor)
 		mutex_unlock(&raw_mutex);
 		return -EBUSY;
 	}
-	if (rawdev->binding) {
-		bdput(rawdev->binding);
+	if (rawdev->binding)
 		module_put(THIS_MODULE);
-	}
+
+	rawdev->binding = dev;
 	if (!dev) {
 		/* unbind */
-		rawdev->binding = NULL;
-		device_destroy(raw_class, MKDEV(RAW_MAJOR, number));
+		device_destroy(raw_class, raw);
 	} else {
-		rawdev->binding = bdget(dev);
-		if (rawdev->binding == NULL) {
-			err = -ENOMEM;
-		} else {
-			dev_t raw = MKDEV(RAW_MAJOR, number);
-			__module_get(THIS_MODULE);
-			device_destroy(raw_class, raw);
-			device_create(raw_class, NULL, raw, NULL,
-				      "raw%d", number);
-		}
+		__module_get(THIS_MODULE);
+		device_destroy(raw_class, raw);
+		device_create(raw_class, NULL, raw, NULL, "raw%d", number);
 	}
 	mutex_unlock(&raw_mutex);
 	return err;
@@ -192,18 +188,9 @@ static int bind_set(int number, u64 major, u64 minor)
 
 static int bind_get(int number, dev_t *dev)
 {
-	struct raw_device_data *rawdev;
-	struct block_device *bdev;
-
 	if (number <= 0 || number >= max_raw_minors)
 		return -EINVAL;
-
-	rawdev = &raw_devices[number];
-
-	mutex_lock(&raw_mutex);
-	bdev = rawdev->binding;
-	*dev = bdev ? bdev->bd_dev : 0;
-	mutex_unlock(&raw_mutex);
+	*dev = raw_devices[number].binding;
 	return 0;
 }
 
-- 
2.28.0

[PATCH 08/14] dasd: cleanup dasd_scan_partitions

[Christoph Hellwig]

Use blkdev_get_by_dev instead of bdget_disk + blkdev_get.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/s390/block/dasd_genhd.c | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
index af5b0ecb8f8923..a9698fba9b76ce 100644
--- a/drivers/s390/block/dasd_genhd.c
+++ b/drivers/s390/block/dasd_genhd.c
@@ -101,18 +101,11 @@ int dasd_scan_partitions(struct dasd_block *block)
 	struct block_device *bdev;
 	int rc;
 
-	bdev = bdget_disk(block->gdp, 0);
-	if (!bdev) {
-		DBF_DEV_EVENT(DBF_ERR, block->base, "%s",
-			      "scan partitions error, bdget returned NULL");
-		return -ENODEV;
-	}
-
-	rc = blkdev_get(bdev, FMODE_READ, NULL);
-	if (rc < 0) {
+	bdev = blkdev_get_by_dev(disk_devt(block->gdp), FMODE_READ, NULL);
+	if (IS_ERR(bdev)) {
 		DBF_DEV_EVENT(DBF_ERR, block->base,
-			      "scan partitions error, blkdev_get returned %d",
-			      rc);
+			      "scan partitions error, blkdev_get returned %ld",
+			      PTR_ERR(bdev));
 		return -ENODEV;
 	}
 
-- 
2.28.0

[PATCH 09/14] ocfs2: cleanup o2hb_region_dev_store

[Christoph Hellwig]

Use blkdev_get_by_dev instead of igrab (aka open coded bdgrab) +
blkdev_get.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
---
 fs/ocfs2/cluster/heartbeat.c | 28 ++++++++++------------------
 1 file changed, 10 insertions(+), 18 deletions(-)

diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index 89d13e0705fe7b..0179a73a3fa2c4 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -1766,7 +1766,6 @@ static ssize_t o2hb_region_dev_store(struct config_item *item,
 	int sectsize;
 	char *p = (char *)page;
 	struct fd f;
-	struct inode *inode;
 	ssize_t ret = -EINVAL;
 	int live_threshold;
 
@@ -1793,20 +1792,16 @@ static ssize_t o2hb_region_dev_store(struct config_item *item,
 	    reg->hr_block_bytes == 0)
 		goto out2;
 
-	inode = igrab(f.file->f_mapping->host);
-	if (inode == NULL)
+	if (!S_ISBLK(f.file->f_mapping->host->i_mode))
 		goto out2;
 
-	if (!S_ISBLK(inode->i_mode))
-		goto out3;
-
-	reg->hr_bdev = I_BDEV(f.file->f_mapping->host);
-	ret = blkdev_get(reg->hr_bdev, FMODE_WRITE | FMODE_READ, NULL);
-	if (ret) {
+	reg->hr_bdev = blkdev_get_by_dev(f.file->f_mapping->host->i_rdev,
+					 FMODE_WRITE | FMODE_READ, NULL);
+	if (IS_ERR(reg->hr_bdev)) {
+		ret = PTR_ERR(reg->hr_bdev);
 		reg->hr_bdev = NULL;
-		goto out3;
+		goto out2;
 	}
-	inode = NULL;
 
 	bdevname(reg->hr_bdev, reg->hr_dev_name);
 
@@ -1909,16 +1904,13 @@ static ssize_t o2hb_region_dev_store(struct config_item *item,
 		       config_item_name(&reg->hr_item), reg->hr_dev_name);
 
 out3:
-	iput(inode);
+	if (ret < 0) {
+		blkdev_put(reg->hr_bdev, FMODE_READ | FMODE_WRITE);
+		reg->hr_bdev = NULL;
+	}
 out2:
 	fdput(f);
 out:
-	if (ret < 0) {
-		if (reg->hr_bdev) {
-			blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
-			reg->hr_bdev = NULL;
-		}
-	}
 	return ret;
 }
 
-- 
2.28.0

[PATCH 10/14] mm: cleanup claim_swapfile

[Christoph Hellwig]

Use blkdev_get_by_dev instead of bdgrab + blkdev_get.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 mm/swapfile.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 12f59e641b5e29..7438c4affc75fa 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2920,10 +2920,10 @@ static int claim_swapfile(struct swap_info_struct *p, struct inode *inode)
 	int error;
 
 	if (S_ISBLK(inode->i_mode)) {
-		p->bdev = bdgrab(I_BDEV(inode));
-		error = blkdev_get(p->bdev,
+		p->bdev = blkdev_get_by_dev(inode->i_rdev,
 				   FMODE_READ | FMODE_WRITE | FMODE_EXCL, p);
-		if (error < 0) {
+		if (IS_ERR(p->bdev)) {
+			error = PTR_ERR(p->bdev);
 			p->bdev = NULL;
 			return error;
 		}
-- 
2.28.0

[PATCH 11/14] PM: rewrite is_hibernate_resume_dev to not require an inode

[Christoph Hellwig]

Just check the dev_t to help simplifying the code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 fs/block_dev.c          |  2 +-
 include/linux/suspend.h |  4 ++--
 kernel/power/user.c     | 12 ++++++------
 3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 1a9325f4315769..2898d69be6b3e4 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1885,7 +1885,7 @@ ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (bdev_read_only(I_BDEV(bd_inode)))
 		return -EPERM;
 
-	if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode))
+	if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev))
 		return -ETXTBSY;
 
 	if (!iov_iter_count(from))
diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index cb9afad82a90c8..8af13ba60c7e45 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -473,9 +473,9 @@ static inline int hibernate_quiet_exec(int (*func)(void *data), void *data) {
 #endif /* CONFIG_HIBERNATION */
 
 #ifdef CONFIG_HIBERNATION_SNAPSHOT_DEV
-int is_hibernate_resume_dev(const struct inode *);
+int is_hibernate_resume_dev(dev_t dev);
 #else
-static inline int is_hibernate_resume_dev(const struct inode *i) { return 0; }
+static inline int is_hibernate_resume_dev(dev_t dev) { return 0; }
 #endif
 
 /* Hibernation and suspend events */
diff --git a/kernel/power/user.c b/kernel/power/user.c
index d5eedc2baa2a10..b5815685b944fe 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -35,12 +35,12 @@ static struct snapshot_data {
 	bool ready;
 	bool platform_support;
 	bool free_bitmaps;
-	struct inode *bd_inode;
+	dev_t dev;
 } snapshot_state;
 
-int is_hibernate_resume_dev(const struct inode *bd_inode)
+int is_hibernate_resume_dev(dev_t dev)
 {
-	return hibernation_available() && snapshot_state.bd_inode == bd_inode;
+	return hibernation_available() && snapshot_state.dev == dev;
 }
 
 static int snapshot_open(struct inode *inode, struct file *filp)
@@ -101,7 +101,7 @@ static int snapshot_open(struct inode *inode, struct file *filp)
 	data->frozen = false;
 	data->ready = false;
 	data->platform_support = false;
-	data->bd_inode = NULL;
+	data->dev = 0;
 
  Unlock:
 	unlock_system_sleep();
@@ -117,7 +117,7 @@ static int snapshot_release(struct inode *inode, struct file *filp)
 
 	swsusp_free();
 	data = filp->private_data;
-	data->bd_inode = NULL;
+	data->dev = 0;
 	free_all_swap_pages(data->swap);
 	if (data->frozen) {
 		pm_restore_gfp_mask();
@@ -245,7 +245,7 @@ static int snapshot_set_swap_area(struct snapshot_data *data,
 	if (data->swap < 0)
 		return -ENODEV;
 
-	data->bd_inode = bdev->bd_inode;
+	data->dev = bdev->bd_dev;
 	bdput(bdev);
 	return 0;
 }
-- 
2.28.0

[PATCH 12/14] mm: split swap_type_of

[Christoph Hellwig]

swap_type_of is used for two entirely different purposes:

 (1) check what swap type a given device/offset corresponds to
 (2) find the first available swap device that can be written to

Mixing both in a single function creates an unreadable mess.  Create two
separate functions instead, and switch both to pass a dev_t instead of
a struct block_device to further simplify the code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 include/linux/swap.h |  3 ++-
 kernel/power/swap.c  | 17 ++++++++---------
 kernel/power/user.c  | 16 ++++------------
 mm/swapfile.c        | 39 +++++++++++++++++++++------------------
 4 files changed, 35 insertions(+), 40 deletions(-)

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 661046994db4b9..4340a7b6e7a1dc 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -467,7 +467,8 @@ extern int swapcache_prepare(swp_entry_t);
 extern void swap_free(swp_entry_t);
 extern void swapcache_free_entries(swp_entry_t *entries, int n);
 extern int free_swap_and_cache(swp_entry_t);
-extern int swap_type_of(dev_t, sector_t, struct block_device **);
+int swap_type_of(dev_t device, sector_t offset);
+int find_first_swap(dev_t *device);
 extern unsigned int count_swap_pages(int, int);
 extern sector_t map_swap_page(struct page *, struct block_device **);
 extern sector_t swapdev_block(int, pgoff_t);
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 01e2858b5fe367..9d3ffbfe08dbf6 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -335,12 +335,17 @@ static int swsusp_swap_check(void)
 {
 	int res;
 
-	res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
-			&hib_resume_bdev);
+	if (swsusp_resume_device)
+		res = swap_type_of(swsusp_resume_device, swsusp_resume_block);
+	else
+		res = find_first_swap(&swsusp_resume_device);
 	if (res < 0)
 		return res;
-
 	root_swap = res;
+
+	hib_resume_bdev = bdget(swsusp_resume_device);
+	if (!hib_resume_bdev)
+		return -ENOMEM;
 	res = blkdev_get(hib_resume_bdev, FMODE_WRITE, NULL);
 	if (res)
 		return res;
@@ -349,12 +354,6 @@ static int swsusp_swap_check(void)
 	if (res < 0)
 		blkdev_put(hib_resume_bdev, FMODE_WRITE);
 
-	/*
-	 * Update the resume device to the one actually used,
-	 * so the test_resume mode can use it in case it is
-	 * invoked from hibernate() to test the snapshot.
-	 */
-	swsusp_resume_device = hib_resume_bdev->bd_dev;
 	return res;
 }
 
diff --git a/kernel/power/user.c b/kernel/power/user.c
index b5815685b944fe..6510a8f7687f42 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -69,8 +69,7 @@ static int snapshot_open(struct inode *inode, struct file *filp)
 	memset(&data->handle, 0, sizeof(struct snapshot_handle));
 	if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
 		/* Hibernating.  The image device should be accessible. */
-		data->swap = swsusp_resume_device ?
-			swap_type_of(swsusp_resume_device, 0, NULL) : -1;
+		data->swap = swap_type_of(swsusp_resume_device, 0);
 		data->mode = O_RDONLY;
 		data->free_bitmaps = false;
 		error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
@@ -210,7 +209,6 @@ struct compat_resume_swap_area {
 static int snapshot_set_swap_area(struct snapshot_data *data,
 		void __user *argp)
 {
-	struct block_device *bdev;
 	sector_t offset;
 	dev_t swdev;
 
@@ -237,16 +235,10 @@ static int snapshot_set_swap_area(struct snapshot_data *data,
 	 * User space encodes device types as two-byte values,
 	 * so we need to recode them
 	 */
-	if (!swdev) {
-		data->swap = -1;
-		return -EINVAL;
-	}
-	data->swap = swap_type_of(swdev, offset, &bdev);
+	data->swap = swap_type_of(swdev, offset);
 	if (data->swap < 0)
-		return -ENODEV;
-
-	data->dev = bdev->bd_dev;
-	bdput(bdev);
+		return swdev ? -ENODEV : -EINVAL;
+	data->dev = swdev;
 	return 0;
 }
 
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 7438c4affc75fa..b90f8692074397 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1801,13 +1801,12 @@ int free_swap_and_cache(swp_entry_t entry)
  *
  * This is needed for the suspend to disk (aka swsusp).
  */
-int swap_type_of(dev_t device, sector_t offset, struct block_device **bdev_p)
+int swap_type_of(dev_t device, sector_t offset)
 {
-	struct block_device *bdev = NULL;
 	int type;
 
-	if (device)
-		bdev = bdget(device);
+	if (!device)
+		return -1;
 
 	spin_lock(&swap_lock);
 	for (type = 0; type < nr_swapfiles; type++) {
@@ -1816,30 +1815,34 @@ int swap_type_of(dev_t device, sector_t offset, struct block_device **bdev_p)
 		if (!(sis->flags & SWP_WRITEOK))
 			continue;
 
-		if (!bdev) {
-			if (bdev_p)
-				*bdev_p = bdgrab(sis->bdev);
-
-			spin_unlock(&swap_lock);
-			return type;
-		}
-		if (bdev == sis->bdev) {
+		if (device == sis->bdev->bd_dev) {
 			struct swap_extent *se = first_se(sis);
 
 			if (se->start_block == offset) {
-				if (bdev_p)
-					*bdev_p = bdgrab(sis->bdev);
-
 				spin_unlock(&swap_lock);
-				bdput(bdev);
 				return type;
 			}
 		}
 	}
 	spin_unlock(&swap_lock);
-	if (bdev)
-		bdput(bdev);
+	return -ENODEV;
+}
 
+int find_first_swap(dev_t *device)
+{
+	int type;
+
+	spin_lock(&swap_lock);
+	for (type = 0; type < nr_swapfiles; type++) {
+		struct swap_info_struct *sis = swap_info[type];
+
+		if (!(sis->flags & SWP_WRITEOK))
+			continue;
+		*device = sis->bdev->bd_dev;
+		spin_unlock(&swap_lock);
+		return type;
+	}
+	spin_unlock(&swap_lock);
 	return -ENODEV;
 }
 
-- 
2.28.0

[PATCH 13/14] PM: mm: cleanup swsusp_swap_check

[Christoph Hellwig]

Use blkdev_get_by_dev instead of bdget + blkdev_get.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 kernel/power/swap.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 9d3ffbfe08dbf6..71385bedcc3a49 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -343,12 +343,10 @@ static int swsusp_swap_check(void)
 		return res;
 	root_swap = res;
 
-	hib_resume_bdev = bdget(swsusp_resume_device);
-	if (!hib_resume_bdev)
-		return -ENOMEM;
-	res = blkdev_get(hib_resume_bdev, FMODE_WRITE, NULL);
-	if (res)
-		return res;
+	hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device, FMODE_WRITE,
+			NULL);
+	if (IS_ERR(hib_resume_bdev))
+		return PTR_ERR(hib_resume_bdev);
 
 	res = set_blocksize(hib_resume_bdev, PAGE_SIZE);
 	if (res < 0)
-- 
2.28.0

[PATCH 14/14] block: mark blkdev_get static

[Christoph Hellwig]

There are no users outside the core block code left now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/block_dev.c         | 3 +--
 include/linux/blkdev.h | 1 -
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 2898d69be6b3e4..6b9d19ffa5af7b 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1616,7 +1616,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
  * RETURNS:
  * 0 on success, -errno on failure.
  */
-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;
 
@@ -1637,7 +1637,6 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
 	bdput(bdev);
 	return ret;
 }
-EXPORT_SYMBOL(blkdev_get);
 
 /**
  * blkdev_get_by_path - open a block device by name
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 5bd96fbab9b4c8..14117995091224 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1975,7 +1975,6 @@ void blkdev_show(struct seq_file *seqf, off_t offset);
 #define BLKDEV_MAJOR_MAX	0
 #endif
 
-int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder);
 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);
-- 
2.28.0

Re: [PATCH 08/14] dasd: cleanup dasd_scan_partitions

[Sergei Shtylyov]

Hello!

On 21.09.2020 10:19, Christoph Hellwig wrote:

> Use blkdev_get_by_dev instead of bdget_disk + blkdev_get.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   drivers/s390/block/dasd_genhd.c | 15 ++++-----------
>   1 file changed, 4 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
> index af5b0ecb8f8923..a9698fba9b76ce 100644
> --- a/drivers/s390/block/dasd_genhd.c
> +++ b/drivers/s390/block/dasd_genhd.c
> @@ -101,18 +101,11 @@ int dasd_scan_partitions(struct dasd_block *block)
>   	struct block_device *bdev;
>   	int rc;
>   
> -	bdev = bdget_disk(block->gdp, 0);
> -	if (!bdev) {
> -		DBF_DEV_EVENT(DBF_ERR, block->base, "%s",
> -			      "scan partitions error, bdget returned NULL");
> -		return -ENODEV;
> -	}
> -
> -	rc = blkdev_get(bdev, FMODE_READ, NULL);
> -	if (rc < 0) {
> +	bdev = blkdev_get_by_dev(disk_devt(block->gdp), FMODE_READ, NULL);
> +	if (IS_ERR(bdev)) {
>   		DBF_DEV_EVENT(DBF_ERR, block->base,
> -			      "scan partitions error, blkdev_get returned %d",
> -			      rc);
> +			      "scan partitions error, blkdev_get returned %ld",

    blkdev_get_by_dev() now?

> +			      PTR_ERR(bdev));
>   		return -ENODEV;
>   	}
>   

MBR, Sergei

Re: [PATCH 11/14] PM: rewrite is_hibernate_resume_dev to not require an inode

[Pavel Machek]

[-- Attachment #1: Type: text/plain, Size: 403 bytes --]

On Mon 2020-09-21 09:19:55, Christoph Hellwig wrote:
> Just check the dev_t to help simplifying the code.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Acked-by: Pavel Machek <pavel@ucw.cz>

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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Re: [PATCH 08/14] dasd: cleanup dasd_scan_partitions

[Stefan Haberland]

Am 21.09.20 um 09:19 schrieb Christoph Hellwig:
> Use blkdev_get_by_dev instead of bdget_disk + blkdev_get.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Beside what Sergei mentioned...

Reviewed-by: Stefan Haberland <sth@linux.ibm.com>


> ---
>  drivers/s390/block/dasd_genhd.c | 15 ++++-----------
>  1 file changed, 4 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
> index af5b0ecb8f8923..a9698fba9b76ce 100644
> --- a/drivers/s390/block/dasd_genhd.c
> +++ b/drivers/s390/block/dasd_genhd.c
> @@ -101,18 +101,11 @@ int dasd_scan_partitions(struct dasd_block *block)
>  	struct block_device *bdev;
>  	int rc;
>  
> -	bdev = bdget_disk(block->gdp, 0);
> -	if (!bdev) {
> -		DBF_DEV_EVENT(DBF_ERR, block->base, "%s",
> -			      "scan partitions error, bdget returned NULL");
> -		return -ENODEV;
> -	}
> -
> -	rc = blkdev_get(bdev, FMODE_READ, NULL);
> -	if (rc < 0) {
> +	bdev = blkdev_get_by_dev(disk_devt(block->gdp), FMODE_READ, NULL);
> +	if (IS_ERR(bdev)) {
>  		DBF_DEV_EVENT(DBF_ERR, block->base,
> -			      "scan partitions error, blkdev_get returned %d",
> -			      rc);
> +			      "scan partitions error, blkdev_get returned %ld",
> +			      PTR_ERR(bdev));
>  		return -ENODEV;
>  	}
>  

Re: remove blkdev_get as a public API v2

[Jens Axboe]

On 9/21/20 1:19 AM, Christoph Hellwig wrote:
> Hi Jens,
> 
> this series removes blkdev_get as a public API, leaving it as just an
> implementation detail of blkdev_get_by_path and blkdev_get_by_dev.  The
> reason for that is that blkdev_get is a very confusing API that requires
> a struct block_device to be fed in, but then actually consumes the
> reference.  And it turns out just using the two above mentioned APIs
> actually significantly simplifies the code as well.
> 
> Changes since v1:
>  - fix a mismerged that left a stray bdget_disk around
>  - factour the partition scan at registration time code into a new
>    helper.

Applied for 5.10, thanks.

-- 
Jens Axboe

Re: [PATCH 01/14] block: move the NEED_PART_SCAN flag to struct gendisk

[Jan Kara]

On Thu 17-09-20 18:57:07, Christoph Hellwig wrote:
> We can only scan for partitions on the whole disk, so move the flag
> from struct block_device to struct gendisk.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Makes sense. You can add:

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

								Honza

> ---
>  block/genhd.c             | 4 ++--
>  drivers/block/nbd.c       | 8 ++++----
>  drivers/ide/ide-gd.c      | 2 +-
>  fs/block_dev.c            | 7 +++----
>  include/linux/blk_types.h | 4 +---
>  include/linux/genhd.h     | 2 ++
>  6 files changed, 13 insertions(+), 14 deletions(-)
> 
> diff --git a/block/genhd.c b/block/genhd.c
> index 9d060e79eb31d8..7b56203c90a303 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -731,7 +731,7 @@ static void register_disk(struct device *parent, struct gendisk *disk,
>  	if (!bdev)
>  		goto exit;
>  
> -	set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
> +	set_bit(GD_NEED_PART_SCAN, &disk->state);
>  	err = blkdev_get(bdev, FMODE_READ, NULL);
>  	if (err < 0)
>  		goto exit;
> @@ -2112,7 +2112,7 @@ bool bdev_check_media_change(struct block_device *bdev)
>  	if (__invalidate_device(bdev, true))
>  		pr_warn("VFS: busy inodes on changed media %s\n",
>  			bdev->bd_disk->disk_name);
> -	set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
> +	set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
>  	return true;
>  }
>  EXPORT_SYMBOL(bdev_check_media_change);
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index 15eed210feeff4..2dca0aab0a9a25 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -315,7 +315,7 @@ static void nbd_size_update(struct nbd_device *nbd)
>  			bd_set_nr_sectors(bdev, nr_sectors);
>  			set_blocksize(bdev, config->blksize);
>  		} else
> -			set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
> +			set_bit(GD_NEED_PART_SCAN, &nbd->disk->state);
>  		bdput(bdev);
>  	}
>  	kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
> @@ -1322,7 +1322,7 @@ static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *b
>  		return ret;
>  
>  	if (max_part)
> -		set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
> +		set_bit(GD_NEED_PART_SCAN, &nbd->disk->state);
>  	mutex_unlock(&nbd->config_lock);
>  	ret = wait_event_interruptible(config->recv_wq,
>  					 atomic_read(&config->recv_threads) == 0);
> @@ -1500,9 +1500,9 @@ static int nbd_open(struct block_device *bdev, fmode_t mode)
>  		refcount_set(&nbd->config_refs, 1);
>  		refcount_inc(&nbd->refs);
>  		mutex_unlock(&nbd->config_lock);
> -		set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
> +		set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
>  	} else if (nbd_disconnected(nbd->config)) {
> -		set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
> +		set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
>  	}
>  out:
>  	mutex_unlock(&nbd_index_mutex);
> diff --git a/drivers/ide/ide-gd.c b/drivers/ide/ide-gd.c
> index 661e2aa9c96784..e2b6c82586ce8b 100644
> --- a/drivers/ide/ide-gd.c
> +++ b/drivers/ide/ide-gd.c
> @@ -230,7 +230,7 @@ static int ide_gd_open(struct block_device *bdev, fmode_t mode)
>  				bdev->bd_disk->disk_name);
>  		drive->disk_ops->get_capacity(drive);
>  		set_capacity(disk, ide_gd_capacity(drive));
> -		set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
> +		set_bit(GD_NEED_PART_SCAN, &disk->state);
>  	} else if (drive->dev_flags & IDE_DFLAG_FORMAT_IN_PROGRESS) {
>  		ret = -EBUSY;
>  		goto out_put_idkp;
> diff --git a/fs/block_dev.c b/fs/block_dev.c
> index 0b34955b9e360f..1a9325f4315769 100644
> --- a/fs/block_dev.c
> +++ b/fs/block_dev.c
> @@ -910,7 +910,6 @@ struct block_device *bdget(dev_t dev)
>  		bdev->bd_super = NULL;
>  		bdev->bd_inode = inode;
>  		bdev->bd_part_count = 0;
> -		bdev->bd_flags = 0;
>  		inode->i_mode = S_IFBLK;
>  		inode->i_rdev = dev;
>  		inode->i_bdev = bdev;
> @@ -1385,7 +1384,7 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)
>  
>  	lockdep_assert_held(&bdev->bd_mutex);
>  
> -	clear_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
> +	clear_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
>  
>  rescan:
>  	ret = blk_drop_partitions(bdev);
> @@ -1509,7 +1508,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
>  			 * The latter is necessary to prevent ghost
>  			 * partitions on a removed medium.
>  			 */
> -			if (test_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags) &&
> +			if (test_bit(GD_NEED_PART_SCAN, &disk->state) &&
>  			    (!ret || ret == -ENOMEDIUM))
>  				bdev_disk_changed(bdev, ret == -ENOMEDIUM);
>  
> @@ -1539,7 +1538,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
>  			if (bdev->bd_disk->fops->open)
>  				ret = bdev->bd_disk->fops->open(bdev, mode);
>  			/* the same as first opener case, read comment there */
> -			if (test_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags) &&
> +			if (test_bit(GD_NEED_PART_SCAN, &disk->state) &&
>  			    (!ret || ret == -ENOMEDIUM))
>  				bdev_disk_changed(bdev, ret == -ENOMEDIUM);
>  			if (ret)
> diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
> index 6ffa783e16335e..eb20e28184ab19 100644
> --- a/include/linux/blk_types.h
> +++ b/include/linux/blk_types.h
> @@ -19,8 +19,6 @@ struct cgroup_subsys_state;
>  typedef void (bio_end_io_t) (struct bio *);
>  struct bio_crypt_ctx;
>  
> -#define BDEV_NEED_PART_SCAN		0
> -
>  struct block_device {
>  	dev_t			bd_dev;
>  	int			bd_openers;
> @@ -39,7 +37,7 @@ struct block_device {
>  	struct hd_struct *	bd_part;
>  	/* number of times partitions within this device have been opened. */
>  	unsigned		bd_part_count;
> -	unsigned long		bd_flags;
> +
>  	spinlock_t		bd_size_lock; /* for bd_inode->i_size updates */
>  	struct gendisk *	bd_disk;
>  	struct backing_dev_info *bd_bdi;
> diff --git a/include/linux/genhd.h b/include/linux/genhd.h
> index 1c97cf84f011a7..38f23d75701379 100644
> --- a/include/linux/genhd.h
> +++ b/include/linux/genhd.h
> @@ -191,6 +191,8 @@ struct gendisk {
>  	void *private_data;
>  
>  	int flags;
> +	unsigned long state;
> +#define GD_NEED_PART_SCAN		0
>  	struct rw_semaphore lookup_sem;
>  	struct kobject *slave_dir;
>  
> -- 
> 2.28.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

[PATCH 01/14] block: move the NEED_PART_SCAN flag to struct gendisk

[Christoph Hellwig]

We can only scan for partitions on the whole disk, so move the flag
from struct block_device to struct gendisk.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c             | 4 ++--
 drivers/block/nbd.c       | 8 ++++----
 drivers/ide/ide-gd.c      | 2 +-
 fs/block_dev.c            | 7 +++----
 include/linux/blk_types.h | 4 +---
 include/linux/genhd.h     | 2 ++
 6 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 9d060e79eb31d8..7b56203c90a303 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -731,7 +731,7 @@ static void register_disk(struct device *parent, struct gendisk *disk,
 	if (!bdev)
 		goto exit;
 
-	set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
+	set_bit(GD_NEED_PART_SCAN, &disk->state);
 	err = blkdev_get(bdev, FMODE_READ, NULL);
 	if (err < 0)
 		goto exit;
@@ -2112,7 +2112,7 @@ bool bdev_check_media_change(struct block_device *bdev)
 	if (__invalidate_device(bdev, true))
 		pr_warn("VFS: busy inodes on changed media %s\n",
 			bdev->bd_disk->disk_name);
-	set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
+	set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
 	return true;
 }
 EXPORT_SYMBOL(bdev_check_media_change);
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 15eed210feeff4..2dca0aab0a9a25 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -315,7 +315,7 @@ static void nbd_size_update(struct nbd_device *nbd)
 			bd_set_nr_sectors(bdev, nr_sectors);
 			set_blocksize(bdev, config->blksize);
 		} else
-			set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
+			set_bit(GD_NEED_PART_SCAN, &nbd->disk->state);
 		bdput(bdev);
 	}
 	kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
@@ -1322,7 +1322,7 @@ static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *b
 		return ret;
 
 	if (max_part)
-		set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
+		set_bit(GD_NEED_PART_SCAN, &nbd->disk->state);
 	mutex_unlock(&nbd->config_lock);
 	ret = wait_event_interruptible(config->recv_wq,
 					 atomic_read(&config->recv_threads) == 0);
@@ -1500,9 +1500,9 @@ static int nbd_open(struct block_device *bdev, fmode_t mode)
 		refcount_set(&nbd->config_refs, 1);
 		refcount_inc(&nbd->refs);
 		mutex_unlock(&nbd->config_lock);
-		set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
+		set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
 	} else if (nbd_disconnected(nbd->config)) {
-		set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
+		set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
 	}
 out:
 	mutex_unlock(&nbd_index_mutex);
diff --git a/drivers/ide/ide-gd.c b/drivers/ide/ide-gd.c
index 661e2aa9c96784..e2b6c82586ce8b 100644
--- a/drivers/ide/ide-gd.c
+++ b/drivers/ide/ide-gd.c
@@ -230,7 +230,7 @@ static int ide_gd_open(struct block_device *bdev, fmode_t mode)
 				bdev->bd_disk->disk_name);
 		drive->disk_ops->get_capacity(drive);
 		set_capacity(disk, ide_gd_capacity(drive));
-		set_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
+		set_bit(GD_NEED_PART_SCAN, &disk->state);
 	} else if (drive->dev_flags & IDE_DFLAG_FORMAT_IN_PROGRESS) {
 		ret = -EBUSY;
 		goto out_put_idkp;
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 0b34955b9e360f..1a9325f4315769 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -910,7 +910,6 @@ struct block_device *bdget(dev_t dev)
 		bdev->bd_super = NULL;
 		bdev->bd_inode = inode;
 		bdev->bd_part_count = 0;
-		bdev->bd_flags = 0;
 		inode->i_mode = S_IFBLK;
 		inode->i_rdev = dev;
 		inode->i_bdev = bdev;
@@ -1385,7 +1384,7 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 
 	lockdep_assert_held(&bdev->bd_mutex);
 
-	clear_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags);
+	clear_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
 
 rescan:
 	ret = blk_drop_partitions(bdev);
@@ -1509,7 +1508,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
 			 * The latter is necessary to prevent ghost
 			 * partitions on a removed medium.
 			 */
-			if (test_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags) &&
+			if (test_bit(GD_NEED_PART_SCAN, &disk->state) &&
 			    (!ret || ret == -ENOMEDIUM))
 				bdev_disk_changed(bdev, ret == -ENOMEDIUM);
 
@@ -1539,7 +1538,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
 			if (bdev->bd_disk->fops->open)
 				ret = bdev->bd_disk->fops->open(bdev, mode);
 			/* the same as first opener case, read comment there */
-			if (test_bit(BDEV_NEED_PART_SCAN, &bdev->bd_flags) &&
+			if (test_bit(GD_NEED_PART_SCAN, &disk->state) &&
 			    (!ret || ret == -ENOMEDIUM))
 				bdev_disk_changed(bdev, ret == -ENOMEDIUM);
 			if (ret)
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 6ffa783e16335e..eb20e28184ab19 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -19,8 +19,6 @@ struct cgroup_subsys_state;
 typedef void (bio_end_io_t) (struct bio *);
 struct bio_crypt_ctx;
 
-#define BDEV_NEED_PART_SCAN		0
-
 struct block_device {
 	dev_t			bd_dev;
 	int			bd_openers;
@@ -39,7 +37,7 @@ struct block_device {
 	struct hd_struct *	bd_part;
 	/* number of times partitions within this device have been opened. */
 	unsigned		bd_part_count;
-	unsigned long		bd_flags;
+
 	spinlock_t		bd_size_lock; /* for bd_inode->i_size updates */
 	struct gendisk *	bd_disk;
 	struct backing_dev_info *bd_bdi;
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 1c97cf84f011a7..38f23d75701379 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -191,6 +191,8 @@ struct gendisk {
 	void *private_data;
 
 	int flags;
+	unsigned long state;
+#define GD_NEED_PART_SCAN		0
 	struct rw_semaphore lookup_sem;
 	struct kobject *slave_dir;
 
-- 
2.28.0