All of lore.kernel.org
 help / color / mirror / Atom feed
* move bd_mutex to the gendisk v2
@ 2021-05-25  6:12 Christoph Hellwig
  2021-05-25  6:12 ` [PATCH 1/8] block: split __blkdev_get Christoph Hellwig
                   ` (8 more replies)
  0 siblings, 9 replies; 26+ messages in thread
From: Christoph Hellwig @ 2021-05-25  6:12 UTC (permalink / raw)
  To: Jens Axboe, Song Liu
  Cc: Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

Hi all,

this series first cleans up gendisk allocation in the md driver to remove
the ERESTARTSYS hack in blkdev_get, then further refactors blkdev_get
and then finally moves bd_mutex into the gendisk as having separate locks
for the whole device vs partitions just complicates locking in places that
add an remove partitions a lot.

Changes since v1:
 - rebased to the latest for-5.14/block branch

Diffstat:
 Documentation/filesystems/locking.rst |    2 
 block/genhd.c                         |   59 +++------
 block/ioctl.c                         |    2 
 block/partitions/core.c               |   45 +++----
 drivers/block/loop.c                  |   14 +-
 drivers/block/xen-blkfront.c          |    8 -
 drivers/block/zram/zram_drv.c         |   18 +-
 drivers/block/zram/zram_drv.h         |    2 
 drivers/md/md.h                       |    6 
 drivers/s390/block/dasd_genhd.c       |    8 -
 drivers/scsi/sd.c                     |    4 
 fs/block_dev.c                        |  207 ++++++++++++++++------------------
 fs/btrfs/volumes.c                    |    2 
 fs/super.c                            |    8 -
 include/linux/blk_types.h             |    4 
 include/linux/genhd.h                 |    6 
 init/do_mounts.c                      |   10 -
 17 files changed, 186 insertions(+), 219 deletions(-)

^ permalink raw reply	[flat|nested] 26+ messages in thread
* [PATCH 1/8] block: split __blkdev_get
  2021-05-25  6:12 move bd_mutex to the gendisk v2 Christoph Hellwig
@ 2021-05-25  6:12 ` Christoph Hellwig
  2021-05-25  8:04   ` Hannes Reinecke
  2021-05-25  6:12 ` [PATCH 2/8] block: move sync_blockdev from __blkdev_put to blkdev_put Christoph Hellwig
                   ` (7 subsequent siblings)
  8 siblings, 1 reply; 26+ messages in thread
From: Christoph Hellwig @ 2021-05-25  6:12 UTC (permalink / raw)
  To: Jens Axboe, Song Liu
  Cc: Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi, Ming Lei

Split __blkdev_get into one helper for the whole device, and one for
opening partitions.  This removes the (bounded) recursion when opening
a partition.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
---
 fs/block_dev.c | 118 ++++++++++++++++++++++++-------------------------
 1 file changed, 57 insertions(+), 61 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 6cc4d4cfe0c2..2b5073e3c923 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1290,78 +1290,68 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)
  */
 EXPORT_SYMBOL_GPL(bdev_disk_changed);
 
-/*
- * bd_mutex locking:
- *
- *  mutex_lock(part->bd_mutex)
- *    mutex_lock_nested(whole->bd_mutex, 1)
- */
-static int __blkdev_get(struct block_device *bdev, fmode_t mode)
+static int blkdev_get_whole(struct block_device *bdev, fmode_t mode)
 {
 	struct gendisk *disk = bdev->bd_disk;
 	int ret = 0;
 
-	if (!(disk->flags & GENHD_FL_UP))
-		return -ENXIO;
+	if (disk->fops->open) {
+		ret = disk->fops->open(bdev, mode);
+		if (ret) {
+			/* avoid ghost partitions on a removed medium */
+			if (ret == -ENOMEDIUM &&
+			     test_bit(GD_NEED_PART_SCAN, &disk->state))
+				bdev_disk_changed(bdev, true);
+			return ret;
+		}
+	}
 
 	if (!bdev->bd_openers) {
-		if (!bdev_is_partition(bdev)) {
-			ret = 0;
-			if (disk->fops->open)
-				ret = disk->fops->open(bdev, mode);
+		set_init_blocksize(bdev);
+		if (bdev->bd_bdi == &noop_backing_dev_info)
+			bdev->bd_bdi = bdi_get(disk->queue->backing_dev_info);
+	}
+	if (test_bit(GD_NEED_PART_SCAN, &disk->state))
+		bdev_disk_changed(bdev, false);
+	bdev->bd_openers++;
+	return 0;;
+}
 
-			if (!ret)
-				set_init_blocksize(bdev);
+static int blkdev_get_part(struct block_device *part, fmode_t mode)
+{
+	struct gendisk *disk = part->bd_disk;
+	struct block_device *whole;
+	int ret;
 
-			/*
-			 * If the device is invalidated, rescan partition
-			 * if open succeeded or failed with -ENOMEDIUM.
-			 * The latter is necessary to prevent ghost
-			 * partitions on a removed medium.
-			 */
-			if (test_bit(GD_NEED_PART_SCAN, &disk->state) &&
-			    (!ret || ret == -ENOMEDIUM))
-				bdev_disk_changed(bdev, ret == -ENOMEDIUM);
+	if (part->bd_openers)
+		goto done;
 
-			if (ret)
-				return ret;
-		} else {
-			struct block_device *whole = bdgrab(disk->part0);
-
-			mutex_lock_nested(&whole->bd_mutex, 1);
-			ret = __blkdev_get(whole, mode);
-			if (ret) {
-				mutex_unlock(&whole->bd_mutex);
-				bdput(whole);
-				return ret;
-			}
-			whole->bd_part_count++;
-			mutex_unlock(&whole->bd_mutex);
+	whole = bdgrab(disk->part0);
+	mutex_lock_nested(&whole->bd_mutex, 1);
+	ret = blkdev_get_whole(whole, mode);
+	if (ret) {
+		mutex_unlock(&whole->bd_mutex);
+		goto out_put_whole;
+	}
+	whole->bd_part_count++;
+	mutex_unlock(&whole->bd_mutex);
 
-			if (!bdev_nr_sectors(bdev)) {
-				__blkdev_put(whole, mode, 1);
-				bdput(whole);
-				return -ENXIO;
-			}
-			set_init_blocksize(bdev);
-		}
+	ret = -ENXIO;
+	if (!bdev_nr_sectors(part))
+		goto out_blkdev_put;
 
-		if (bdev->bd_bdi == &noop_backing_dev_info)
-			bdev->bd_bdi = bdi_get(disk->queue->backing_dev_info);
-	} else {
-		if (!bdev_is_partition(bdev)) {
-			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(GD_NEED_PART_SCAN, &disk->state) &&
-			    (!ret || ret == -ENOMEDIUM))
-				bdev_disk_changed(bdev, ret == -ENOMEDIUM);
-			if (ret)
-				return ret;
-		}
-	}
-	bdev->bd_openers++;
+	set_init_blocksize(part);
+	if (part->bd_bdi == &noop_backing_dev_info)
+		part->bd_bdi = bdi_get(disk->queue->backing_dev_info);
+done:
+	part->bd_openers++;
 	return 0;
+
+out_blkdev_put:
+	__blkdev_put(whole, mode, 1);
+out_put_whole:
+	bdput(whole);
+	return ret;
 }
 
 struct block_device *blkdev_get_no_open(dev_t dev)
@@ -1448,7 +1438,13 @@ 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, mode);
+	ret = -ENXIO;
+	if (!(disk->flags & GENHD_FL_UP))
+		goto abort_claiming;
+	if (bdev_is_partition(bdev))
+		ret = blkdev_get_part(bdev, mode);
+	else
+		ret = blkdev_get_whole(bdev, mode);
 	if (ret)
 		goto abort_claiming;
 	if (mode & FMODE_EXCL) {
-- 
2.30.2


^ permalink raw reply related	[flat|nested] 26+ messages in thread
* [PATCH 2/8] block: move sync_blockdev from __blkdev_put to blkdev_put
  2021-05-25  6:12 move bd_mutex to the gendisk v2 Christoph Hellwig
  2021-05-25  6:12 ` [PATCH 1/8] block: split __blkdev_get Christoph Hellwig
@ 2021-05-25  6:12 ` Christoph Hellwig
  2021-05-25  8:05   ` Hannes Reinecke
  2021-05-25  6:12 ` [PATCH 3/8] block: move bd_mutex to struct gendisk Christoph Hellwig
                   ` (6 subsequent siblings)
  8 siblings, 1 reply; 26+ messages in thread
From: Christoph Hellwig @ 2021-05-25  6:12 UTC (permalink / raw)
  To: Jens Axboe, Song Liu
  Cc: Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi, Ming Lei

Do the early unlocked syncing even earlier to move more code out of
the recursive path.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
---
 fs/block_dev.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 2b5073e3c923..41d2d9708bf8 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1552,16 +1552,6 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
 	struct gendisk *disk = bdev->bd_disk;
 	struct block_device *victim = NULL;
 
-	/*
-	 * Sync early if it looks like we're the last one.  If someone else
-	 * opens the block device between now and the decrement of bd_openers
-	 * then we did a sync that we didn't need to, but that's not the end
-	 * of the world and we want to avoid long (could be several minute)
-	 * syncs while holding the mutex.
-	 */
-	if (bdev->bd_openers == 1)
-		sync_blockdev(bdev);
-
 	mutex_lock_nested(&bdev->bd_mutex, for_part);
 	if (for_part)
 		bdev->bd_part_count--;
@@ -1588,6 +1578,16 @@ void blkdev_put(struct block_device *bdev, fmode_t mode)
 {
 	struct gendisk *disk = bdev->bd_disk;
 
+	/*
+	 * Sync early if it looks like we're the last one.  If someone else
+	 * opens the block device between now and the decrement of bd_openers
+	 * then we did a sync that we didn't need to, but that's not the end
+	 * of the world and we want to avoid long (could be several minute)
+	 * syncs while holding the mutex.
+	 */
+	if (bdev->bd_openers == 1)
+		sync_blockdev(bdev);
+
 	mutex_lock(&bdev->bd_mutex);
 
 	if (mode & FMODE_EXCL) {
-- 
2.30.2


^ permalink raw reply related	[flat|nested] 26+ messages in thread
* [PATCH 3/8] block: move bd_mutex to struct gendisk
  2021-05-25  6:12 move bd_mutex to the gendisk v2 Christoph Hellwig
  2021-05-25  6:12 ` [PATCH 1/8] block: split __blkdev_get Christoph Hellwig
  2021-05-25  6:12 ` [PATCH 2/8] block: move sync_blockdev from __blkdev_put to blkdev_put Christoph Hellwig
@ 2021-05-25  6:12 ` Christoph Hellwig
  2021-05-25  8:06   ` Hannes Reinecke
                     ` (2 more replies)
  2021-05-25  6:12 ` [PATCH 4/8] block: move adjusting bd_part_count out of __blkdev_get Christoph Hellwig
                   ` (5 subsequent siblings)
  8 siblings, 3 replies; 26+ messages in thread
From: Christoph Hellwig @ 2021-05-25  6:12 UTC (permalink / raw)
  To: Jens Axboe, Song Liu
  Cc: Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

Replace the per-block device bd_mutex with a per-gendisk open_mutex,
thus simplifying locking wherever we deal with partitions.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 Documentation/filesystems/locking.rst |  2 +-
 block/genhd.c                         |  7 ++---
 block/partitions/core.c               | 24 ++++++++---------
 drivers/block/loop.c                  | 14 +++++-----
 drivers/block/xen-blkfront.c          |  8 +++---
 drivers/block/zram/zram_drv.c         | 18 ++++++-------
 drivers/block/zram/zram_drv.h         |  2 +-
 drivers/md/md.h                       |  6 ++---
 drivers/s390/block/dasd_genhd.c       |  8 +++---
 drivers/scsi/sd.c                     |  4 +--
 fs/block_dev.c                        | 37 +++++++++++----------------
 fs/btrfs/volumes.c                    |  2 +-
 fs/super.c                            |  8 +++---
 include/linux/blk_types.h             |  1 -
 include/linux/genhd.h                 |  3 +++
 15 files changed, 68 insertions(+), 76 deletions(-)

diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst
index 1e894480115b..2183fd8cc350 100644
--- a/Documentation/filesystems/locking.rst
+++ b/Documentation/filesystems/locking.rst
@@ -480,7 +480,7 @@ prototypes::
 locking rules:
 
 ======================= ===================
-ops			bd_mutex
+ops			open_mutex
 ======================= ===================
 open:			yes
 release:		yes
diff --git a/block/genhd.c b/block/genhd.c
index 9f8cb7beaad1..7c88c52c6589 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -607,10 +607,10 @@ void del_gendisk(struct gendisk *disk)
 	blk_integrity_del(disk);
 	disk_del_events(disk);
 
-	mutex_lock(&disk->part0->bd_mutex);
+	mutex_lock(&disk->open_mutex);
 	disk->flags &= ~GENHD_FL_UP;
 	blk_drop_partitions(disk);
-	mutex_unlock(&disk->part0->bd_mutex);
+	mutex_unlock(&disk->open_mutex);
 
 	fsync_bdev(disk->part0);
 	__invalidate_device(disk->part0, true);
@@ -1295,6 +1295,7 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
 		goto out_free_disk;
 
 	disk->node_id = node_id;
+	mutex_init(&disk->open_mutex);
 	xa_init(&disk->part_tbl);
 	if (xa_insert(&disk->part_tbl, 0, disk->part0, GFP_KERNEL))
 		goto out_destroy_part_tbl;
@@ -1512,7 +1513,7 @@ void disk_unblock_events(struct gendisk *disk)
  * doesn't clear the events from @disk->ev.
  *
  * CONTEXT:
- * If @mask is non-zero must be called with bdev->bd_mutex held.
+ * If @mask is non-zero must be called with disk->open_mutex held.
  */
 void disk_flush_events(struct gendisk *disk, unsigned int mask)
 {
diff --git a/block/partitions/core.c b/block/partitions/core.c
index dc60ecf46fe6..0d33f55a7d78 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -282,7 +282,7 @@ struct device_type part_type = {
 };
 
 /*
- * Must be called either with bd_mutex held, before a disk can be opened or
+ * Must be called either with open_mutex held, before a disk can be opened or
  * after all disk users are gone.
  */
 static void delete_partition(struct block_device *part)
@@ -311,7 +311,7 @@ static ssize_t whole_disk_show(struct device *dev,
 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
+ * Must be called either with open_mutex held, before a disk can be opened or
  * after all disk users are gone.
  */
 static struct block_device *add_partition(struct gendisk *disk, int partno,
@@ -450,15 +450,15 @@ int bdev_add_partition(struct block_device *bdev, int partno,
 {
 	struct block_device *part;
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&bdev->bd_disk->open_mutex);
 	if (partition_overlaps(bdev->bd_disk, start, length, -1)) {
-		mutex_unlock(&bdev->bd_mutex);
+		mutex_unlock(&bdev->bd_disk->open_mutex);
 		return -EBUSY;
 	}
 
 	part = add_partition(bdev->bd_disk, partno, start, length,
 			ADDPART_FLAG_NONE, NULL);
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&bdev->bd_disk->open_mutex);
 	return PTR_ERR_OR_ZERO(part);
 }
 
@@ -471,8 +471,7 @@ int bdev_del_partition(struct block_device *bdev, int partno)
 	if (!part)
 		return -ENXIO;
 
-	mutex_lock(&part->bd_mutex);
-	mutex_lock_nested(&bdev->bd_mutex, 1);
+	mutex_lock(&bdev->bd_disk->open_mutex);
 
 	ret = -EBUSY;
 	if (part->bd_openers)
@@ -481,8 +480,7 @@ int bdev_del_partition(struct block_device *bdev, int partno)
 	delete_partition(part);
 	ret = 0;
 out_unlock:
-	mutex_unlock(&bdev->bd_mutex);
-	mutex_unlock(&part->bd_mutex);
+	mutex_unlock(&bdev->bd_disk->open_mutex);
 	bdput(part);
 	return ret;
 }
@@ -497,8 +495,7 @@ int bdev_resize_partition(struct block_device *bdev, int partno,
 	if (!part)
 		return -ENXIO;
 
-	mutex_lock(&part->bd_mutex);
-	mutex_lock_nested(&bdev->bd_mutex, 1);
+	mutex_lock(&bdev->bd_disk->open_mutex);
 	ret = -EINVAL;
 	if (start != part->bd_start_sect)
 		goto out_unlock;
@@ -511,8 +508,7 @@ int bdev_resize_partition(struct block_device *bdev, int partno,
 
 	ret = 0;
 out_unlock:
-	mutex_unlock(&part->bd_mutex);
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&bdev->bd_disk->open_mutex);
 	bdput(part);
 	return ret;
 }
@@ -538,7 +534,7 @@ void blk_drop_partitions(struct gendisk *disk)
 	struct block_device *part;
 	unsigned long idx;
 
-	lockdep_assert_held(&disk->part0->bd_mutex);
+	lockdep_assert_held(&disk->open_mutex);
 
 	xa_for_each_start(&disk->part_tbl, idx, part, 1) {
 		if (!bdgrab(part))
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index d58d68f3c7cd..95c570f5923f 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -652,9 +652,9 @@ static void loop_reread_partitions(struct loop_device *lo,
 {
 	int rc;
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&bdev->bd_disk->open_mutex);
 	rc = bdev_disk_changed(bdev, false);
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&bdev->bd_disk->open_mutex);
 	if (rc)
 		pr_warn("%s: partition scan of loop%d (%s) failed (rc=%d)\n",
 			__func__, lo->lo_number, lo->lo_file_name, rc);
@@ -747,7 +747,7 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev,
 	mutex_unlock(&lo->lo_mutex);
 	/*
 	 * We must drop file reference outside of lo_mutex as dropping
-	 * the file ref can take bd_mutex which creates circular locking
+	 * the file ref can take open_mutex which creates circular locking
 	 * dependency.
 	 */
 	fput(old_file);
@@ -1260,7 +1260,7 @@ static int __loop_clr_fd(struct loop_device *lo, bool release)
 	mutex_unlock(&lo->lo_mutex);
 	if (partscan) {
 		/*
-		 * bd_mutex has been held already in release path, so don't
+		 * open_mutex has been held already in release path, so don't
 		 * acquire it if this function is called in such case.
 		 *
 		 * If the reread partition isn't from release path, lo_refcnt
@@ -1268,10 +1268,10 @@ static int __loop_clr_fd(struct loop_device *lo, bool release)
 		 * current holder is released.
 		 */
 		if (!release)
-			mutex_lock(&bdev->bd_mutex);
+			mutex_lock(&bdev->bd_disk->open_mutex);
 		err = bdev_disk_changed(bdev, false);
 		if (!release)
-			mutex_unlock(&bdev->bd_mutex);
+			mutex_unlock(&bdev->bd_disk->open_mutex);
 		if (err)
 			pr_warn("%s: partition scan of loop%d failed (rc=%d)\n",
 				__func__, lo_number, err);
@@ -1298,7 +1298,7 @@ static int __loop_clr_fd(struct loop_device *lo, bool release)
 	/*
 	 * Need not hold lo_mutex to fput backing file. Calling fput holding
 	 * lo_mutex triggers a circular lock dependency possibility warning as
-	 * fput can take bd_mutex which is usually taken before lo_mutex.
+	 * fput can take open_mutex which is usually taken before lo_mutex.
 	 */
 	if (filp)
 		fput(filp);
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 10df39a8b18d..f2c1aedcdf5a 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -2163,7 +2163,7 @@ static void blkfront_closing(struct blkfront_info *info)
 		return;
 	}
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&bdev->bd_disk->open_mutex);
 
 	if (bdev->bd_openers) {
 		xenbus_dev_error(xbdev, -EBUSY,
@@ -2174,7 +2174,7 @@ static void blkfront_closing(struct blkfront_info *info)
 		xenbus_frontend_closed(xbdev);
 	}
 
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&bdev->bd_disk->open_mutex);
 	bdput(bdev);
 }
 
@@ -2531,7 +2531,7 @@ static int blkfront_remove(struct xenbus_device *xbdev)
 	 * isn't closed yet, we let release take care of it.
 	 */
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&disk->open_mutex);
 	info = disk->private_data;
 
 	dev_warn(disk_to_dev(disk),
@@ -2546,7 +2546,7 @@ static int blkfront_remove(struct xenbus_device *xbdev)
 		mutex_unlock(&blkfront_mutex);
 	}
 
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&disk->open_mutex);
 	bdput(bdev);
 
 	return 0;
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index cf8deecc39ef..b3bf544493d3 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1781,24 +1781,24 @@ static ssize_t reset_store(struct device *dev,
 	zram = dev_to_zram(dev);
 	bdev = zram->disk->part0;
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&bdev->bd_disk->open_mutex);
 	/* Do not reset an active device or claimed device */
 	if (bdev->bd_openers || zram->claim) {
-		mutex_unlock(&bdev->bd_mutex);
+		mutex_unlock(&bdev->bd_disk->open_mutex);
 		return -EBUSY;
 	}
 
 	/* From now on, anyone can't open /dev/zram[0-9] */
 	zram->claim = true;
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&bdev->bd_disk->open_mutex);
 
 	/* Make sure all the pending I/O are finished */
 	fsync_bdev(bdev);
 	zram_reset_device(zram);
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&bdev->bd_disk->open_mutex);
 	zram->claim = false;
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&bdev->bd_disk->open_mutex);
 
 	return len;
 }
@@ -1808,7 +1808,7 @@ 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));
+	WARN_ON(!mutex_is_locked(&bdev->bd_disk->open_mutex));
 
 	zram = bdev->bd_disk->private_data;
 	/* zram was claimed to reset so open request fails */
@@ -1982,14 +1982,14 @@ static int zram_remove(struct zram *zram)
 {
 	struct block_device *bdev = zram->disk->part0;
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&bdev->bd_disk->open_mutex);
 	if (bdev->bd_openers || zram->claim) {
-		mutex_unlock(&bdev->bd_mutex);
+		mutex_unlock(&bdev->bd_disk->open_mutex);
 		return -EBUSY;
 	}
 
 	zram->claim = true;
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&bdev->bd_disk->open_mutex);
 
 	zram_debugfs_unregister(zram);
 
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index 419a7e8281ee..74c411911b6e 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -112,7 +112,7 @@ struct zram {
 	/*
 	 * zram is claimed so open request will be failed
 	 */
-	bool claim; /* Protected by bdev->bd_mutex */
+	bool claim; /* Protected by disk->open_mutex */
 	struct file *backing_dev;
 #ifdef CONFIG_ZRAM_WRITEBACK
 	spinlock_t wb_limit_lock;
diff --git a/drivers/md/md.h b/drivers/md/md.h
index fb7eab58cfd5..a88086d4110c 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -395,10 +395,10 @@ struct mddev {
 	 * that we are never stopping an array while it is open.
 	 * 'reconfig_mutex' protects all other reconfiguration.
 	 * These locks are separate due to conflicting interactions
-	 * with bdev->bd_mutex.
+	 * with disk->open_mutex.
 	 * Lock ordering is:
-	 *  reconfig_mutex -> bd_mutex
-	 *  bd_mutex -> open_mutex:  e.g. __blkdev_get -> md_open
+	 *  reconfig_mutex -> disk->open_mutex
+	 *  disk->open_mutex -> open_mutex:  e.g. __blkdev_get -> md_open
 	 */
 	struct mutex			open_mutex;
 	struct mutex			reconfig_mutex;
diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
index 8d6587ec73e2..bf2082d461c7 100644
--- a/drivers/s390/block/dasd_genhd.c
+++ b/drivers/s390/block/dasd_genhd.c
@@ -109,9 +109,9 @@ int dasd_scan_partitions(struct dasd_block *block)
 		return -ENODEV;
 	}
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&block->gdp->open_mutex);
 	rc = bdev_disk_changed(bdev, false);
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&block->gdp->open_mutex);
 	if (rc)
 		DBF_DEV_EVENT(DBF_ERR, block->base,
 				"scan partitions error, rc %d", rc);
@@ -145,9 +145,9 @@ void dasd_destroy_partitions(struct dasd_block *block)
 	bdev = block->bdev;
 	block->bdev = NULL;
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&bdev->bd_disk->open_mutex);
 	bdev_disk_changed(bdev, true);
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&bdev->bd_disk->open_mutex);
 
 	/* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */
 	blkdev_put(bdev, FMODE_READ);
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index cb3c37d1e009..d3ff723af879 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1400,7 +1400,7 @@ static void sd_uninit_command(struct scsi_cmnd *SCpnt)
  *	In the latter case @inode and @filp carry an abridged amount
  *	of information as noted above.
  *
- *	Locking: called with bdev->bd_mutex held.
+ *	Locking: called with bdev->bd_disk->open_mutex held.
  **/
 static int sd_open(struct block_device *bdev, fmode_t mode)
 {
@@ -1476,7 +1476,7 @@ static int sd_open(struct block_device *bdev, fmode_t mode)
  *	Note: may block (uninterruptible) if error recovery is underway
  *	on this disk.
  *
- *	Locking: called with bdev->bd_mutex held.
+ *	Locking: called with bdev->bd_disk->open_mutex held.
  **/
 static void sd_release(struct gendisk *disk, fmode_t mode)
 {
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 41d2d9708bf8..e094806c3a0c 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -895,7 +895,6 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
 	mapping_set_gfp_mask(&inode->i_data, GFP_USER);
 
 	bdev = I_BDEV(inode);
-	mutex_init(&bdev->bd_mutex);
 	mutex_init(&bdev->bd_fsfreeze_mutex);
 	spin_lock_init(&bdev->bd_size_lock);
 	bdev->bd_disk = disk;
@@ -1154,7 +1153,7 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
 	struct bd_holder_disk *holder;
 	int ret = 0;
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&bdev->bd_disk->open_mutex);
 
 	WARN_ON_ONCE(!bdev->bd_holder);
 
@@ -1199,7 +1198,7 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
 out_free:
 	kfree(holder);
 out_unlock:
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&bdev->bd_disk->open_mutex);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(bd_link_disk_holder);
@@ -1218,7 +1217,7 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
 {
 	struct bd_holder_disk *holder;
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&bdev->bd_disk->open_mutex);
 
 	holder = bd_find_holder_disk(bdev, disk);
 
@@ -1230,7 +1229,7 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
 		kfree(holder);
 	}
 
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&bdev->bd_disk->open_mutex);
 }
 EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
 #endif
@@ -1242,7 +1241,7 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 	struct gendisk *disk = bdev->bd_disk;
 	int ret = 0;
 
-	lockdep_assert_held(&bdev->bd_mutex);
+	lockdep_assert_held(&disk->open_mutex);
 
 	if (!(disk->flags & GENHD_FL_UP))
 		return -ENXIO;
@@ -1327,14 +1326,10 @@ static int blkdev_get_part(struct block_device *part, fmode_t mode)
 		goto done;
 
 	whole = bdgrab(disk->part0);
-	mutex_lock_nested(&whole->bd_mutex, 1);
 	ret = blkdev_get_whole(whole, mode);
-	if (ret) {
-		mutex_unlock(&whole->bd_mutex);
+	if (ret)
 		goto out_put_whole;
-	}
 	whole->bd_part_count++;
-	mutex_unlock(&whole->bd_mutex);
 
 	ret = -ENXIO;
 	if (!bdev_nr_sectors(part))
@@ -1437,7 +1432,7 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 
 	disk_block_events(disk);
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&disk->open_mutex);
 	ret = -ENXIO;
 	if (!(disk->flags & GENHD_FL_UP))
 		goto abort_claiming;
@@ -1463,7 +1458,7 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 			unblock_events = false;
 		}
 	}
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&disk->open_mutex);
 
 	if (unblock_events)
 		disk_unblock_events(disk);
@@ -1472,7 +1467,7 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 abort_claiming:
 	if (mode & FMODE_EXCL)
 		bd_abort_claiming(bdev, holder);
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&disk->open_mutex);
 	disk_unblock_events(disk);
 put_blkdev:
 	blkdev_put_no_open(bdev);
@@ -1552,7 +1547,6 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
 	struct gendisk *disk = bdev->bd_disk;
 	struct block_device *victim = NULL;
 
-	mutex_lock_nested(&bdev->bd_mutex, for_part);
 	if (for_part)
 		bdev->bd_part_count--;
 
@@ -1567,7 +1561,6 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
 
 	if (!bdev_is_partition(bdev) && disk->fops->release)
 		disk->fops->release(disk, mode);
-	mutex_unlock(&bdev->bd_mutex);
 	if (victim) {
 		__blkdev_put(victim, mode, 1);
 		bdput(victim);
@@ -1588,15 +1581,14 @@ void blkdev_put(struct block_device *bdev, fmode_t mode)
 	if (bdev->bd_openers == 1)
 		sync_blockdev(bdev);
 
-	mutex_lock(&bdev->bd_mutex);
-
+	mutex_lock(&disk->open_mutex);
 	if (mode & FMODE_EXCL) {
 		struct block_device *whole = bdev_whole(bdev);
 		bool bdev_free;
 
 		/*
 		 * Release a claim on the device.  The holder fields
-		 * are protected with bdev_lock.  bd_mutex is to
+		 * are protected with bdev_lock.  open_mutex is to
 		 * synchronize disk_holder unlinking.
 		 */
 		spin_lock(&bdev_lock);
@@ -1627,9 +1619,10 @@ void blkdev_put(struct block_device *bdev, fmode_t mode)
 	 * from userland - e.g. eject(1).
 	 */
 	disk_flush_events(disk, DISK_EVENT_MEDIA_CHANGE);
-	mutex_unlock(&bdev->bd_mutex);
 
 	__blkdev_put(bdev, mode, 0);
+	mutex_unlock(&disk->open_mutex);
+
 	blkdev_put_no_open(bdev);
 }
 EXPORT_SYMBOL(blkdev_put);
@@ -1936,10 +1929,10 @@ void iterate_bdevs(void (*func)(struct block_device *, void *), void *arg)
 		old_inode = inode;
 		bdev = I_BDEV(inode);
 
-		mutex_lock(&bdev->bd_mutex);
+		mutex_lock(&bdev->bd_disk->open_mutex);
 		if (bdev->bd_openers)
 			func(bdev, arg);
-		mutex_unlock(&bdev->bd_mutex);
+		mutex_unlock(&bdev->bd_disk->open_mutex);
 
 		spin_lock(&blockdev_superblock->s_inode_list_lock);
 	}
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 47d27059d064..f246eb2772e9 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1247,7 +1247,7 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 	lockdep_assert_held(&uuid_mutex);
 	/*
 	 * The device_list_mutex cannot be taken here in case opening the
-	 * underlying device takes further locks like bd_mutex.
+	 * underlying device takes further locks like open_mutex.
 	 *
 	 * We also don't need the lock here as this is called during mount and
 	 * exclusion is provided by uuid_mutex
diff --git a/fs/super.c b/fs/super.c
index 11b7e7213fd1..91b7f156735b 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1277,9 +1277,9 @@ int get_tree_bdev(struct fs_context *fc,
 		}
 
 		/*
-		 * s_umount nests inside bd_mutex during
+		 * s_umount nests inside open_mutex during
 		 * __invalidate_device().  blkdev_put() acquires
-		 * bd_mutex and can't be called under s_umount.  Drop
+		 * open_mutex and can't be called under s_umount.  Drop
 		 * s_umount temporarily.  This is safe as we're
 		 * holding an active reference.
 		 */
@@ -1352,9 +1352,9 @@ struct dentry *mount_bdev(struct file_system_type *fs_type,
 		}
 
 		/*
-		 * s_umount nests inside bd_mutex during
+		 * s_umount nests inside open_mutex during
 		 * __invalidate_device().  blkdev_put() acquires
-		 * bd_mutex and can't be called under s_umount.  Drop
+		 * open_mutex and can't be called under s_umount.  Drop
 		 * s_umount temporarily.  This is safe as we're
 		 * holding an active reference.
 		 */
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index db026b6ec15a..a09660671fa4 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -29,7 +29,6 @@ struct block_device {
 	int			bd_openers;
 	struct inode *		bd_inode;	/* will die */
 	struct super_block *	bd_super;
-	struct mutex		bd_mutex;	/* open/close mutex */
 	void *			bd_claiming;
 	struct device		bd_device;
 	void *			bd_holder;
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 6fc26f7bdf71..55072e17ea82 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -153,6 +153,9 @@ struct gendisk {
 	unsigned long state;
 #define GD_NEED_PART_SCAN		0
 #define GD_READ_ONLY			1
+
+	struct mutex open_mutex;	/* open/close mutex */
+
 	struct kobject *slave_dir;
 
 	struct timer_rand_state *random;
-- 
2.30.2


^ permalink raw reply related	[flat|nested] 26+ messages in thread
* [PATCH 4/8] block: move adjusting bd_part_count out of __blkdev_get
  2021-05-25  6:12 move bd_mutex to the gendisk v2 Christoph Hellwig
                   ` (2 preceding siblings ...)
  2021-05-25  6:12 ` [PATCH 3/8] block: move bd_mutex to struct gendisk Christoph Hellwig
@ 2021-05-25  6:12 ` Christoph Hellwig
  2021-05-25  8:18   ` Hannes Reinecke
  2021-05-26  1:59   ` Ming Lei
  2021-05-25  6:12 ` [PATCH 5/8] block: split __blkdev_put Christoph Hellwig
                   ` (4 subsequent siblings)
  8 siblings, 2 replies; 26+ messages in thread
From: Christoph Hellwig @ 2021-05-25  6:12 UTC (permalink / raw)
  To: Jens Axboe, Song Liu
  Cc: Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

Keep in the callers and thus remove the for_part argument.  This mirrors
what is done on the blkdev_get side and slightly simplifies
blkdev_get_part as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/block_dev.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index e094806c3a0c..43dce929e7ee 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1234,7 +1234,7 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
 EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
 #endif
 
-static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);
+static void __blkdev_put(struct block_device *bdev, fmode_t mode);
 
 int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 {
@@ -1329,12 +1329,12 @@ static int blkdev_get_part(struct block_device *part, fmode_t mode)
 	ret = blkdev_get_whole(whole, mode);
 	if (ret)
 		goto out_put_whole;
-	whole->bd_part_count++;
 
 	ret = -ENXIO;
 	if (!bdev_nr_sectors(part))
 		goto out_blkdev_put;
 
+	whole->bd_part_count++;
 	set_init_blocksize(part);
 	if (part->bd_bdi == &noop_backing_dev_info)
 		part->bd_bdi = bdi_get(disk->queue->backing_dev_info);
@@ -1343,7 +1343,7 @@ static int blkdev_get_part(struct block_device *part, fmode_t mode)
 	return 0;
 
 out_blkdev_put:
-	__blkdev_put(whole, mode, 1);
+	__blkdev_put(whole, mode);
 out_put_whole:
 	bdput(whole);
 	return ret;
@@ -1542,14 +1542,11 @@ static int blkdev_open(struct inode * inode, struct file * filp)
 	return 0;
 }
 
-static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
+static void __blkdev_put(struct block_device *bdev, fmode_t mode)
 {
 	struct gendisk *disk = bdev->bd_disk;
 	struct block_device *victim = NULL;
 
-	if (for_part)
-		bdev->bd_part_count--;
-
 	if (!--bdev->bd_openers) {
 		WARN_ON_ONCE(bdev->bd_holders);
 		sync_blockdev(bdev);
@@ -1562,7 +1559,8 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
 	if (!bdev_is_partition(bdev) && disk->fops->release)
 		disk->fops->release(disk, mode);
 	if (victim) {
-		__blkdev_put(victim, mode, 1);
+		victim->bd_part_count--;
+		__blkdev_put(victim, mode);
 		bdput(victim);
 	}
 }
@@ -1620,7 +1618,7 @@ void blkdev_put(struct block_device *bdev, fmode_t mode)
 	 */
 	disk_flush_events(disk, DISK_EVENT_MEDIA_CHANGE);
 
-	__blkdev_put(bdev, mode, 0);
+	__blkdev_put(bdev, mode);
 	mutex_unlock(&disk->open_mutex);
 
 	blkdev_put_no_open(bdev);
-- 
2.30.2


^ permalink raw reply related	[flat|nested] 26+ messages in thread
* [PATCH 5/8] block: split __blkdev_put
  2021-05-25  6:12 move bd_mutex to the gendisk v2 Christoph Hellwig
                   ` (3 preceding siblings ...)
  2021-05-25  6:12 ` [PATCH 4/8] block: move adjusting bd_part_count out of __blkdev_get Christoph Hellwig
@ 2021-05-25  6:12 ` Christoph Hellwig
  2021-05-25  8:19   ` Hannes Reinecke
  2021-05-26  2:05   ` Ming Lei
  2021-05-25  6:12 ` [PATCH 6/8] block: move bd_part_count to struct gendisk Christoph Hellwig
                   ` (3 subsequent siblings)
  8 siblings, 2 replies; 26+ messages in thread
From: Christoph Hellwig @ 2021-05-25  6:12 UTC (permalink / raw)
  To: Jens Axboe, Song Liu
  Cc: Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

Split __blkdev_put into one helper for the whole device, and one for
partitions as well as another shared helper for flushing the block
device inode mapping.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/block_dev.c | 58 ++++++++++++++++++++++++++++----------------------
 1 file changed, 32 insertions(+), 26 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 43dce929e7ee..cd45b54e86b4 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1234,7 +1234,13 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
 EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
 #endif
 
-static void __blkdev_put(struct block_device *bdev, fmode_t mode);
+static void blkdev_flush_mapping(struct block_device *bdev)
+{
+	WARN_ON_ONCE(bdev->bd_holders);
+	sync_blockdev(bdev);
+	kill_bdev(bdev);
+	bdev_write_inode(bdev);
+}
 
 int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 {
@@ -1316,6 +1322,14 @@ static int blkdev_get_whole(struct block_device *bdev, fmode_t mode)
 	return 0;;
 }
 
+static void blkdev_put_whole(struct block_device *bdev, fmode_t mode)
+{
+	if (!--bdev->bd_openers)
+		blkdev_flush_mapping(bdev);
+	if (bdev->bd_disk->fops->release)
+		bdev->bd_disk->fops->release(bdev->bd_disk, mode);
+}
+
 static int blkdev_get_part(struct block_device *part, fmode_t mode)
 {
 	struct gendisk *disk = part->bd_disk;
@@ -1343,12 +1357,24 @@ static int blkdev_get_part(struct block_device *part, fmode_t mode)
 	return 0;
 
 out_blkdev_put:
-	__blkdev_put(whole, mode);
+	blkdev_put_whole(whole, mode);
 out_put_whole:
 	bdput(whole);
 	return ret;
 }
 
+static void blkdev_put_part(struct block_device *part, fmode_t mode)
+{
+	struct block_device *whole = bdev_whole(part);
+
+	if (--part->bd_openers)
+		return;
+	blkdev_flush_mapping(part);
+	whole->bd_part_count--;
+	blkdev_put_whole(whole, mode);
+	bdput(whole);
+}
+
 struct block_device *blkdev_get_no_open(dev_t dev)
 {
 	struct block_device *bdev;
@@ -1542,29 +1568,6 @@ static int blkdev_open(struct inode * inode, struct file * filp)
 	return 0;
 }
 
-static void __blkdev_put(struct block_device *bdev, fmode_t mode)
-{
-	struct gendisk *disk = bdev->bd_disk;
-	struct block_device *victim = NULL;
-
-	if (!--bdev->bd_openers) {
-		WARN_ON_ONCE(bdev->bd_holders);
-		sync_blockdev(bdev);
-		kill_bdev(bdev);
-		bdev_write_inode(bdev);
-		if (bdev_is_partition(bdev))
-			victim = bdev_whole(bdev);
-	}
-
-	if (!bdev_is_partition(bdev) && disk->fops->release)
-		disk->fops->release(disk, mode);
-	if (victim) {
-		victim->bd_part_count--;
-		__blkdev_put(victim, mode);
-		bdput(victim);
-	}
-}
-
 void blkdev_put(struct block_device *bdev, fmode_t mode)
 {
 	struct gendisk *disk = bdev->bd_disk;
@@ -1618,7 +1621,10 @@ void blkdev_put(struct block_device *bdev, fmode_t mode)
 	 */
 	disk_flush_events(disk, DISK_EVENT_MEDIA_CHANGE);
 
-	__blkdev_put(bdev, mode);
+	if (bdev_is_partition(bdev))
+		blkdev_put_part(bdev, mode);
+	else
+		blkdev_put_whole(bdev, mode);
 	mutex_unlock(&disk->open_mutex);
 
 	blkdev_put_no_open(bdev);
-- 
2.30.2


^ permalink raw reply related	[flat|nested] 26+ messages in thread
* [PATCH 6/8] block: move bd_part_count to struct gendisk
  2021-05-25  6:12 move bd_mutex to the gendisk v2 Christoph Hellwig
                   ` (4 preceding siblings ...)
  2021-05-25  6:12 ` [PATCH 5/8] block: split __blkdev_put Christoph Hellwig
@ 2021-05-25  6:12 ` Christoph Hellwig
  2021-05-25  8:20   ` Hannes Reinecke
  2021-05-26  2:09   ` Ming Lei
  2021-05-25  6:13 ` [PATCH 7/8] block: factor out a part_devt helper Christoph Hellwig
                   ` (2 subsequent siblings)
  8 siblings, 2 replies; 26+ messages in thread
From: Christoph Hellwig @ 2021-05-25  6:12 UTC (permalink / raw)
  To: Jens Axboe, Song Liu
  Cc: Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

The bd_part_count value only makes sense for whole devices, so move it
to struct gendisk and give it a more descriptive name.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/ioctl.c             | 2 +-
 fs/block_dev.c            | 6 +++---
 include/linux/blk_types.h | 3 ---
 include/linux/genhd.h     | 1 +
 4 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/block/ioctl.c b/block/ioctl.c
index 8ba1ed8defd0..24beec9ca9c9 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -89,7 +89,7 @@ static int blkdev_reread_part(struct block_device *bdev, fmode_t mode)
 		return -EINVAL;
 	if (!capable(CAP_SYS_ADMIN))
 		return -EACCES;
-	if (bdev->bd_part_count)
+	if (bdev->bd_disk->open_partitions)
 		return -EBUSY;
 
 	/*
diff --git a/fs/block_dev.c b/fs/block_dev.c
index cd45b54e86b4..ac9b3c158a77 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1253,7 +1253,7 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 		return -ENXIO;
 
 rescan:
-	if (bdev->bd_part_count)
+	if (disk->open_partitions)
 		return -EBUSY;
 	sync_blockdev(bdev);
 	invalidate_bdev(bdev);
@@ -1348,7 +1348,7 @@ static int blkdev_get_part(struct block_device *part, fmode_t mode)
 	if (!bdev_nr_sectors(part))
 		goto out_blkdev_put;
 
-	whole->bd_part_count++;
+	disk->open_partitions++;
 	set_init_blocksize(part);
 	if (part->bd_bdi == &noop_backing_dev_info)
 		part->bd_bdi = bdi_get(disk->queue->backing_dev_info);
@@ -1370,7 +1370,7 @@ static void blkdev_put_part(struct block_device *part, fmode_t mode)
 	if (--part->bd_openers)
 		return;
 	blkdev_flush_mapping(part);
-	whole->bd_part_count--;
+	whole->bd_disk->open_partitions--;
 	blkdev_put_whole(whole, mode);
 	bdput(whole);
 }
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index a09660671fa4..fd3860d18d7e 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -39,9 +39,6 @@ struct block_device {
 #endif
 	struct kobject		*bd_holder_dir;
 	u8			bd_partno;
-	/* number of times partitions within this device have been opened. */
-	unsigned		bd_part_count;
-
 	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 55072e17ea82..a093ec40c0a2 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -155,6 +155,7 @@ struct gendisk {
 #define GD_READ_ONLY			1
 
 	struct mutex open_mutex;	/* open/close mutex */
+	unsigned open_partitions;	/* number of open partitions */
 
 	struct kobject *slave_dir;
 
-- 
2.30.2


^ permalink raw reply related	[flat|nested] 26+ messages in thread
* [PATCH 7/8] block: factor out a part_devt helper
  2021-05-25  6:12 move bd_mutex to the gendisk v2 Christoph Hellwig
                   ` (5 preceding siblings ...)
  2021-05-25  6:12 ` [PATCH 6/8] block: move bd_part_count to struct gendisk Christoph Hellwig
@ 2021-05-25  6:13 ` Christoph Hellwig
  2021-05-25  8:25   ` Hannes Reinecke
  2021-05-26  2:16   ` Ming Lei
  2021-05-25  6:13 ` [PATCH 8/8] block: remove bdget_disk Christoph Hellwig
  2021-06-01 13:48 ` move bd_mutex to the gendisk v2 Jens Axboe
  8 siblings, 2 replies; 26+ messages in thread
From: Christoph Hellwig @ 2021-05-25  6:13 UTC (permalink / raw)
  To: Jens Axboe, Song Liu
  Cc: Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

Add a helper to find the dev_t for a disk + partno tuple.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c         | 25 +++++++++++++++++--------
 include/linux/genhd.h |  1 +
 init/do_mounts.c      | 10 ++--------
 3 files changed, 20 insertions(+), 16 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 7c88c52c6589..e3de476797de 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1242,6 +1242,19 @@ static int __init proc_genhd_init(void)
 module_init(proc_genhd_init);
 #endif /* CONFIG_PROC_FS */
 
+dev_t part_devt(struct gendisk *disk, u8 partno)
+{
+	struct block_device *part = bdget_disk(disk, partno);
+	dev_t devt = 0;
+
+	if (part) {
+		devt = part->bd_dev;
+		bdput(part);
+	}
+
+	return devt;
+}
+
 dev_t blk_lookup_devt(const char *name, int partno)
 {
 	dev_t devt = MKDEV(0, 0);
@@ -1251,7 +1264,6 @@ 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 block_device *part;
 
 		if (strcmp(dev_name(dev), name))
 			continue;
@@ -1262,13 +1274,10 @@ dev_t blk_lookup_devt(const char *name, int partno)
 			 */
 			devt = MKDEV(MAJOR(dev->devt),
 				     MINOR(dev->devt) + partno);
-			break;
-		}
-		part = bdget_disk(disk, partno);
-		if (part) {
-			devt = part->bd_dev;
-			bdput(part);
-			break;
+		} else {
+			devt = part_devt(disk, partno);
+			if (devt)
+				break;
 		}
 	}
 	class_dev_iter_exit(&iter);
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index a093ec40c0a2..96d55cd06cf6 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -310,6 +310,7 @@ static inline void bd_unlink_disk_holder(struct block_device *bdev,
 }
 #endif /* CONFIG_SYSFS */
 
+dev_t part_devt(struct gendisk *disk, u8 partno);
 dev_t blk_lookup_devt(const char *name, int partno);
 void blk_request_module(dev_t devt);
 #ifdef CONFIG_BLOCK
diff --git a/init/do_mounts.c b/init/do_mounts.c
index a78e44ee6adb..74aede860de7 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -133,14 +133,8 @@ 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 block_device *part;
-
-		part = bdget_disk(dev_to_disk(dev),
-				  dev_to_bdev(dev)->bd_partno + offset);
-		if (part) {
-			devt = part->bd_dev;
-			bdput(part);
-		}
+		devt = part_devt(dev_to_disk(dev),
+				 dev_to_bdev(dev)->bd_partno + offset);
 	} else {
 		devt = dev->devt;
 	}
-- 
2.30.2


^ permalink raw reply related	[flat|nested] 26+ messages in thread
* [PATCH 8/8] block: remove bdget_disk
  2021-05-25  6:12 move bd_mutex to the gendisk v2 Christoph Hellwig
                   ` (6 preceding siblings ...)
  2021-05-25  6:13 ` [PATCH 7/8] block: factor out a part_devt helper Christoph Hellwig
@ 2021-05-25  6:13 ` Christoph Hellwig
  2021-05-25  8:26   ` Hannes Reinecke
  2021-05-26  2:24   ` Ming Lei
  2021-06-01 13:48 ` move bd_mutex to the gendisk v2 Jens Axboe
  8 siblings, 2 replies; 26+ messages in thread
From: Christoph Hellwig @ 2021-05-25  6:13 UTC (permalink / raw)
  To: Jens Axboe, Song Liu
  Cc: Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

Just opencode the xa_load in the callers, as none of them actually
needs a reference to the bdev.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c           | 35 +++++------------------------------
 block/partitions/core.c | 25 ++++++++++++-------------
 include/linux/genhd.h   |  1 -
 3 files changed, 17 insertions(+), 44 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index e3de476797de..2abafe44bf4b 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -692,32 +692,6 @@ void blk_request_module(dev_t devt)
 		request_module("block-major-%d", MAJOR(devt));
 }
 
-/**
- * bdget_disk - do bdget() by gendisk and partition number
- * @disk: gendisk of interest
- * @partno: partition number
- *
- * Find partition @partno from @disk, do bdget() on it.
- *
- * CONTEXT:
- * Don't care.
- *
- * RETURNS:
- * Resulting block_device on success, NULL on failure.
- */
-struct block_device *bdget_disk(struct gendisk *disk, int partno)
-{
-	struct block_device *bdev = NULL;
-
-	rcu_read_lock();
-	bdev = xa_load(&disk->part_tbl, partno);
-	if (bdev && !bdgrab(bdev))
-		bdev = NULL;
-	rcu_read_unlock();
-
-	return bdev;
-}
-
 /*
  * print a full list of all partitions - intended for places where the root
  * filesystem can't be mounted and thus to give the victim some idea of what
@@ -1244,13 +1218,14 @@ module_init(proc_genhd_init);
 
 dev_t part_devt(struct gendisk *disk, u8 partno)
 {
-	struct block_device *part = bdget_disk(disk, partno);
+	struct block_device *part;
 	dev_t devt = 0;
 
-	if (part) {
+	rcu_read_lock();
+	part = xa_load(&disk->part_tbl, partno);
+	if (part)
 		devt = part->bd_dev;
-		bdput(part);
-	}
+	rcu_read_unlock();
 
 	return devt;
 }
diff --git a/block/partitions/core.c b/block/partitions/core.c
index 0d33f55a7d78..325368b9de29 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -325,6 +325,8 @@ static struct block_device *add_partition(struct gendisk *disk, int partno,
 	const char *dname;
 	int err;
 
+	lockdep_assert_held(&disk->open_mutex);
+
 	/*
 	 * disk_max_parts() won't be zero, either GENHD_FL_EXT_DEVT is set
 	 * or 'minors' is passed to alloc_disk().
@@ -464,14 +466,13 @@ int bdev_add_partition(struct block_device *bdev, int partno,
 
 int bdev_del_partition(struct block_device *bdev, int partno)
 {
-	struct block_device *part;
-	int ret;
-
-	part = bdget_disk(bdev->bd_disk, partno);
-	if (!part)
-		return -ENXIO;
+	struct block_device *part = NULL;
+	int ret = -ENXIO;
 
 	mutex_lock(&bdev->bd_disk->open_mutex);
+	part = xa_load(&bdev->bd_disk->part_tbl, partno);
+	if (!part)
+		goto out_unlock;
 
 	ret = -EBUSY;
 	if (part->bd_openers)
@@ -481,21 +482,20 @@ int bdev_del_partition(struct block_device *bdev, int partno)
 	ret = 0;
 out_unlock:
 	mutex_unlock(&bdev->bd_disk->open_mutex);
-	bdput(part);
 	return ret;
 }
 
 int bdev_resize_partition(struct block_device *bdev, int partno,
 		sector_t start, sector_t length)
 {
-	struct block_device *part;
-	int ret = 0;
+	struct block_device *part = NULL;
+	int ret = -ENXIO;
 
-	part = bdget_disk(bdev->bd_disk, partno);
+	mutex_lock(&bdev->bd_disk->open_mutex);
+	part = xa_load(&bdev->bd_disk->part_tbl, partno);
 	if (!part)
-		return -ENXIO;
+		goto out_unlock;
 
-	mutex_lock(&bdev->bd_disk->open_mutex);
 	ret = -EINVAL;
 	if (start != part->bd_start_sect)
 		goto out_unlock;
@@ -509,7 +509,6 @@ int bdev_resize_partition(struct block_device *bdev, int partno,
 	ret = 0;
 out_unlock:
 	mutex_unlock(&bdev->bd_disk->open_mutex);
-	bdput(part);
 	return ret;
 }
 
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 96d55cd06cf6..d06892a0a9ef 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -222,7 +222,6 @@ static inline void add_disk_no_queue_reg(struct gendisk *disk)
 }
 
 extern void del_gendisk(struct gendisk *gp);
-extern struct block_device *bdget_disk(struct gendisk *disk, int partno);
 
 void set_disk_ro(struct gendisk *disk, bool read_only);
 
-- 
2.30.2


^ permalink raw reply related	[flat|nested] 26+ messages in thread
* Re: [PATCH 1/8] block: split __blkdev_get
  2021-05-25  6:12 ` [PATCH 1/8] block: split __blkdev_get Christoph Hellwig
@ 2021-05-25  8:04   ` Hannes Reinecke
  0 siblings, 0 replies; 26+ messages in thread
From: Hannes Reinecke @ 2021-05-25  8:04 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe, Song Liu
  Cc: Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi, Ming Lei

On 5/25/21 8:12 AM, Christoph Hellwig wrote:
> Split __blkdev_get into one helper for the whole device, and one for
> opening partitions.  This removes the (bounded) recursion when opening
> a partition.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Ming Lei <ming.lei@redhat.com>
> ---
>   fs/block_dev.c | 118 ++++++++++++++++++++++++-------------------------
>   1 file changed, 57 insertions(+), 61 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

^ permalink raw reply	[flat|nested] 26+ messages in thread
* Re: [PATCH 2/8] block: move sync_blockdev from __blkdev_put to blkdev_put
  2021-05-25  6:12 ` [PATCH 2/8] block: move sync_blockdev from __blkdev_put to blkdev_put Christoph Hellwig
@ 2021-05-25  8:05   ` Hannes Reinecke
  0 siblings, 0 replies; 26+ messages in thread
From: Hannes Reinecke @ 2021-05-25  8:05 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe, Song Liu
  Cc: Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi, Ming Lei

On 5/25/21 8:12 AM, Christoph Hellwig wrote:
> Do the early unlocked syncing even earlier to move more code out of
> the recursive path.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Ming Lei <ming.lei@redhat.com>
> ---
>   fs/block_dev.c | 20 ++++++++++----------
>   1 file changed, 10 insertions(+), 10 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

^ permalink raw reply	[flat|nested] 26+ messages in thread
* Re: [PATCH 3/8] block: move bd_mutex to struct gendisk
  2021-05-25  6:12 ` [PATCH 3/8] block: move bd_mutex to struct gendisk Christoph Hellwig
@ 2021-05-25  8:06   ` Hannes Reinecke
  2021-05-26  1:06   ` Ming Lei
  2021-05-28  7:27   ` Roger Pau Monné
  2 siblings, 0 replies; 26+ messages in thread
From: Hannes Reinecke @ 2021-05-25  8:06 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe, Song Liu
  Cc: Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

On 5/25/21 8:12 AM, Christoph Hellwig wrote:
> Replace the per-block device bd_mutex with a per-gendisk open_mutex,
> thus simplifying locking wherever we deal with partitions.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   Documentation/filesystems/locking.rst |  2 +-
>   block/genhd.c                         |  7 ++---
>   block/partitions/core.c               | 24 ++++++++---------
>   drivers/block/loop.c                  | 14 +++++-----
>   drivers/block/xen-blkfront.c          |  8 +++---
>   drivers/block/zram/zram_drv.c         | 18 ++++++-------
>   drivers/block/zram/zram_drv.h         |  2 +-
>   drivers/md/md.h                       |  6 ++---
>   drivers/s390/block/dasd_genhd.c       |  8 +++---
>   drivers/scsi/sd.c                     |  4 +--
>   fs/block_dev.c                        | 37 +++++++++++----------------
>   fs/btrfs/volumes.c                    |  2 +-
>   fs/super.c                            |  8 +++---
>   include/linux/blk_types.h             |  1 -
>   include/linux/genhd.h                 |  3 +++
>   15 files changed, 68 insertions(+), 76 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

^ permalink raw reply	[flat|nested] 26+ messages in thread
* Re: [PATCH 4/8] block: move adjusting bd_part_count out of __blkdev_get
  2021-05-25  6:12 ` [PATCH 4/8] block: move adjusting bd_part_count out of __blkdev_get Christoph Hellwig
@ 2021-05-25  8:18   ` Hannes Reinecke
  2021-05-26  1:59   ` Ming Lei
  1 sibling, 0 replies; 26+ messages in thread
From: Hannes Reinecke @ 2021-05-25  8:18 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe, Song Liu
  Cc: Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

On 5/25/21 8:12 AM, Christoph Hellwig wrote:
> Keep in the callers and thus remove the for_part argument.  This mirrors
> what is done on the blkdev_get side and slightly simplifies
> blkdev_get_part as well.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   fs/block_dev.c | 16 +++++++---------
>   1 file changed, 7 insertions(+), 9 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

^ permalink raw reply	[flat|nested] 26+ messages in thread
* Re: [PATCH 5/8] block: split __blkdev_put
  2021-05-25  6:12 ` [PATCH 5/8] block: split __blkdev_put Christoph Hellwig
@ 2021-05-25  8:19   ` Hannes Reinecke
  2021-05-26  2:05   ` Ming Lei
  1 sibling, 0 replies; 26+ messages in thread
From: Hannes Reinecke @ 2021-05-25  8:19 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe, Song Liu
  Cc: Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

On 5/25/21 8:12 AM, Christoph Hellwig wrote:
> Split __blkdev_put into one helper for the whole device, and one for
> partitions as well as another shared helper for flushing the block
> device inode mapping.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   fs/block_dev.c | 58 ++++++++++++++++++++++++++++----------------------
>   1 file changed, 32 insertions(+), 26 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

^ permalink raw reply	[flat|nested] 26+ messages in thread
* Re: [PATCH 6/8] block: move bd_part_count to struct gendisk
  2021-05-25  6:12 ` [PATCH 6/8] block: move bd_part_count to struct gendisk Christoph Hellwig
@ 2021-05-25  8:20   ` Hannes Reinecke
  2021-05-26  2:09   ` Ming Lei
  1 sibling, 0 replies; 26+ messages in thread
From: Hannes Reinecke @ 2021-05-25  8:20 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe, Song Liu
  Cc: Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

On 5/25/21 8:12 AM, Christoph Hellwig wrote:
> The bd_part_count value only makes sense for whole devices, so move it
> to struct gendisk and give it a more descriptive name.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   block/ioctl.c             | 2 +-
>   fs/block_dev.c            | 6 +++---
>   include/linux/blk_types.h | 3 ---
>   include/linux/genhd.h     | 1 +
>   4 files changed, 5 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

^ permalink raw reply	[flat|nested] 26+ messages in thread
* Re: [PATCH 7/8] block: factor out a part_devt helper
  2021-05-25  6:13 ` [PATCH 7/8] block: factor out a part_devt helper Christoph Hellwig
@ 2021-05-25  8:25   ` Hannes Reinecke
  2021-05-26  2:16   ` Ming Lei
  1 sibling, 0 replies; 26+ messages in thread
From: Hannes Reinecke @ 2021-05-25  8:25 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe, Song Liu
  Cc: Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

On 5/25/21 8:13 AM, Christoph Hellwig wrote:
> Add a helper to find the dev_t for a disk + partno tuple.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   block/genhd.c         | 25 +++++++++++++++++--------
>   include/linux/genhd.h |  1 +
>   init/do_mounts.c      | 10 ++--------
>   3 files changed, 20 insertions(+), 16 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

^ permalink raw reply	[flat|nested] 26+ messages in thread
* Re: [PATCH 8/8] block: remove bdget_disk
  2021-05-25  6:13 ` [PATCH 8/8] block: remove bdget_disk Christoph Hellwig
@ 2021-05-25  8:26   ` Hannes Reinecke
  2021-05-26  2:24   ` Ming Lei
  1 sibling, 0 replies; 26+ messages in thread
From: Hannes Reinecke @ 2021-05-25  8:26 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe, Song Liu
  Cc: Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

On 5/25/21 8:13 AM, Christoph Hellwig wrote:
> Just opencode the xa_load in the callers, as none of them actually
> needs a reference to the bdev.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   block/genhd.c           | 35 +++++------------------------------
>   block/partitions/core.c | 25 ++++++++++++-------------
>   include/linux/genhd.h   |  1 -
>   3 files changed, 17 insertions(+), 44 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

^ permalink raw reply	[flat|nested] 26+ messages in thread
* Re: [PATCH 3/8] block: move bd_mutex to struct gendisk
  2021-05-25  6:12 ` [PATCH 3/8] block: move bd_mutex to struct gendisk Christoph Hellwig
  2021-05-25  8:06   ` Hannes Reinecke
@ 2021-05-26  1:06   ` Ming Lei
  2021-05-28  7:27   ` Roger Pau Monné
  2 siblings, 0 replies; 26+ messages in thread
From: Ming Lei @ 2021-05-26  1:06 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Song Liu, Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

On Tue, May 25, 2021 at 08:12:56AM +0200, Christoph Hellwig wrote:
> Replace the per-block device bd_mutex with a per-gendisk open_mutex,
> thus simplifying locking wherever we deal with partitions.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---

Reviewed-by: Ming Lei <ming.lei@redhat.com>

-- 
Ming


^ permalink raw reply	[flat|nested] 26+ messages in thread
* Re: [PATCH 4/8] block: move adjusting bd_part_count out of __blkdev_get
  2021-05-25  6:12 ` [PATCH 4/8] block: move adjusting bd_part_count out of __blkdev_get Christoph Hellwig
  2021-05-25  8:18   ` Hannes Reinecke
@ 2021-05-26  1:59   ` Ming Lei
  1 sibling, 0 replies; 26+ messages in thread
From: Ming Lei @ 2021-05-26  1:59 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Song Liu, Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

On Tue, May 25, 2021 at 08:12:57AM +0200, Christoph Hellwig wrote:
> Keep in the callers and thus remove the for_part argument.  This mirrors
> what is done on the blkdev_get side and slightly simplifies
> blkdev_get_part as well.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Ming Lei <ming.lei@rehat.com>

-- 
Ming


^ permalink raw reply	[flat|nested] 26+ messages in thread
* Re: [PATCH 5/8] block: split __blkdev_put
  2021-05-25  6:12 ` [PATCH 5/8] block: split __blkdev_put Christoph Hellwig
  2021-05-25  8:19   ` Hannes Reinecke
@ 2021-05-26  2:05   ` Ming Lei
  1 sibling, 0 replies; 26+ messages in thread
From: Ming Lei @ 2021-05-26  2:05 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Song Liu, Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

On Tue, May 25, 2021 at 08:12:58AM +0200, Christoph Hellwig wrote:
> Split __blkdev_put into one helper for the whole device, and one for
> partitions as well as another shared helper for flushing the block
> device inode mapping.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Ming Lei <ming.lei@redhat.com>

-- 
Ming


^ permalink raw reply	[flat|nested] 26+ messages in thread
* Re: [PATCH 6/8] block: move bd_part_count to struct gendisk
  2021-05-25  6:12 ` [PATCH 6/8] block: move bd_part_count to struct gendisk Christoph Hellwig
  2021-05-25  8:20   ` Hannes Reinecke
@ 2021-05-26  2:09   ` Ming Lei
  1 sibling, 0 replies; 26+ messages in thread
From: Ming Lei @ 2021-05-26  2:09 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Song Liu, Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

On Tue, May 25, 2021 at 08:12:59AM +0200, Christoph Hellwig wrote:
> The bd_part_count value only makes sense for whole devices, so move it
> to struct gendisk and give it a more descriptive name.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---

Reviewed-by: Ming Lei <ming.lei@redhat.com>

-- 
Ming


^ permalink raw reply	[flat|nested] 26+ messages in thread
* Re: [PATCH 7/8] block: factor out a part_devt helper
  2021-05-25  6:13 ` [PATCH 7/8] block: factor out a part_devt helper Christoph Hellwig
  2021-05-25  8:25   ` Hannes Reinecke
@ 2021-05-26  2:16   ` Ming Lei
  1 sibling, 0 replies; 26+ messages in thread
From: Ming Lei @ 2021-05-26  2:16 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Song Liu, Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

On Tue, May 25, 2021 at 08:13:00AM +0200, Christoph Hellwig wrote:
> Add a helper to find the dev_t for a disk + partno tuple.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Ming Lei <ming.lei@redhat.com>

-- 
Ming


^ permalink raw reply	[flat|nested] 26+ messages in thread
* Re: [PATCH 8/8] block: remove bdget_disk
  2021-05-25  6:13 ` [PATCH 8/8] block: remove bdget_disk Christoph Hellwig
  2021-05-25  8:26   ` Hannes Reinecke
@ 2021-05-26  2:24   ` Ming Lei
  1 sibling, 0 replies; 26+ messages in thread
From: Ming Lei @ 2021-05-26  2:24 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Song Liu, Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

On Tue, May 25, 2021 at 08:13:01AM +0200, Christoph Hellwig wrote:
> Just opencode the xa_load in the callers, as none of them actually
> needs a reference to the bdev.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Ming Lei <ming.lei@redhat.com>

-- 
Ming


^ permalink raw reply	[flat|nested] 26+ messages in thread
* Re: [PATCH 3/8] block: move bd_mutex to struct gendisk
  2021-05-25  6:12 ` [PATCH 3/8] block: move bd_mutex to struct gendisk Christoph Hellwig
  2021-05-25  8:06   ` Hannes Reinecke
  2021-05-26  1:06   ` Ming Lei
@ 2021-05-28  7:27   ` Roger Pau Monné
  2 siblings, 0 replies; 26+ messages in thread
From: Roger Pau Monné @ 2021-05-28  7:27 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Song Liu, Konrad Rzeszutek Wilk, Minchan Kim,
	Nitin Gupta, Stefan Haberland, Jan Hoeppner, linux-block,
	linux-raid, linux-s390, linux-scsi

On Tue, May 25, 2021 at 08:12:56AM +0200, Christoph Hellwig wrote:
> Replace the per-block device bd_mutex with a per-gendisk open_mutex,
> thus simplifying locking wherever we deal with partitions.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  Documentation/filesystems/locking.rst |  2 +-
>  block/genhd.c                         |  7 ++---
>  block/partitions/core.c               | 24 ++++++++---------
>  drivers/block/loop.c                  | 14 +++++-----
>  drivers/block/xen-blkfront.c          |  8 +++---

Acked-by: Roger Pau Monné <roger.pau@citrix.com>

Thanks, Roger.

^ permalink raw reply	[flat|nested] 26+ messages in thread
* Re: move bd_mutex to the gendisk v2
  2021-05-25  6:12 move bd_mutex to the gendisk v2 Christoph Hellwig
                   ` (7 preceding siblings ...)
  2021-05-25  6:13 ` [PATCH 8/8] block: remove bdget_disk Christoph Hellwig
@ 2021-06-01 13:48 ` Jens Axboe
  8 siblings, 0 replies; 26+ messages in thread
From: Jens Axboe @ 2021-06-01 13:48 UTC (permalink / raw)
  To: Christoph Hellwig, Song Liu
  Cc: Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

On 5/25/21 12:12 AM, Christoph Hellwig wrote:
> Hi all,
> 
> this series first cleans up gendisk allocation in the md driver to remove
> the ERESTARTSYS hack in blkdev_get, then further refactors blkdev_get
> and then finally moves bd_mutex into the gendisk as having separate locks
> for the whole device vs partitions just complicates locking in places that
> add an remove partitions a lot.
> 
> Changes since v1:
>  - rebased to the latest for-5.14/block branch
> 
> Diffstat:
>  Documentation/filesystems/locking.rst |    2 
>  block/genhd.c                         |   59 +++------
>  block/ioctl.c                         |    2 
>  block/partitions/core.c               |   45 +++----
>  drivers/block/loop.c                  |   14 +-
>  drivers/block/xen-blkfront.c          |    8 -
>  drivers/block/zram/zram_drv.c         |   18 +-
>  drivers/block/zram/zram_drv.h         |    2 
>  drivers/md/md.h                       |    6 
>  drivers/s390/block/dasd_genhd.c       |    8 -
>  drivers/scsi/sd.c                     |    4 
>  fs/block_dev.c                        |  207 ++++++++++++++++------------------
>  fs/btrfs/volumes.c                    |    2 
>  fs/super.c                            |    8 -
>  include/linux/blk_types.h             |    4 
>  include/linux/genhd.h                 |    6 
>  init/do_mounts.c                      |   10 -
>  17 files changed, 186 insertions(+), 219 deletions(-)

Applied, thanks. Took a bit of hand-applying, but we got there. Please
check the final result.

-- 
Jens Axboe


^ permalink raw reply	[flat|nested] 26+ messages in thread
* [PATCH 6/8] block: move bd_part_count to struct gendisk
  2021-05-12  6:18 move bd_mutex to the gendisk (resend) Christoph Hellwig
@ 2021-05-12  6:18 ` Christoph Hellwig
  0 siblings, 0 replies; 26+ messages in thread
From: Christoph Hellwig @ 2021-05-12  6:18 UTC (permalink / raw)
  To: Jens Axboe, Song Liu
  Cc: Konrad Rzeszutek Wilk, Roger Pau Monné,
	Minchan Kim, Nitin Gupta, Stefan Haberland, Jan Hoeppner,
	linux-block, linux-raid, linux-s390, linux-scsi

The bd_part_count value only makes sense for whole devices, so move it
to struct gendisk and give it a more descriptive name.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/ioctl.c             | 2 +-
 fs/block_dev.c            | 6 +++---
 include/linux/blk_types.h | 3 ---
 include/linux/genhd.h     | 1 +
 4 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/block/ioctl.c b/block/ioctl.c
index 8ba1ed8defd0..24beec9ca9c9 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -89,7 +89,7 @@ static int blkdev_reread_part(struct block_device *bdev, fmode_t mode)
 		return -EINVAL;
 	if (!capable(CAP_SYS_ADMIN))
 		return -EACCES;
-	if (bdev->bd_part_count)
+	if (bdev->bd_disk->open_partitions)
 		return -EBUSY;
 
 	/*
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 4bcab845ac05..8dd8e2fd1401 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1250,7 +1250,7 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 	lockdep_assert_held(&disk->open_mutex);
 
 rescan:
-	if (bdev->bd_part_count)
+	if (disk->open_partitions)
 		return -EBUSY;
 	sync_blockdev(bdev);
 	invalidate_bdev(bdev);
@@ -1345,7 +1345,7 @@ static int blkdev_get_part(struct block_device *part, fmode_t mode)
 	if (!(disk->flags & GENHD_FL_UP) || !bdev_nr_sectors(part))
 		goto out_blkdev_put;
 
-	whole->bd_part_count++;
+	disk->open_partitions++;
 	set_init_blocksize(part);
 	if (part->bd_bdi == &noop_backing_dev_info)
 		part->bd_bdi = bdi_get(disk->queue->backing_dev_info);
@@ -1367,7 +1367,7 @@ static void blkdev_put_part(struct block_device *part, fmode_t mode)
 	if (--part->bd_openers)
 		return;
 	blkdev_flush_mapping(part);
-	whole->bd_part_count--;
+	whole->bd_disk->open_partitions--;
 	blkdev_put_whole(whole, mode);
 	bdput(whole);
 }
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index a09660671fa4..fd3860d18d7e 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -39,9 +39,6 @@ struct block_device {
 #endif
 	struct kobject		*bd_holder_dir;
 	u8			bd_partno;
-	/* number of times partitions within this device have been opened. */
-	unsigned		bd_part_count;
-
 	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 0747f1853f39..74fd28ddac70 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -155,6 +155,7 @@ struct gendisk {
 #define GD_READ_ONLY			1
 
 	struct mutex open_mutex;	/* open/close mutex */
+	unsigned open_partitions;	/* number of open partitions */
 
 	struct kobject *slave_dir;
 
-- 
2.30.2


^ permalink raw reply related	[flat|nested] 26+ messages in thread
end of thread, other threads:[~2021-06-01 13:48 UTC | newest]

Thread overview: 26+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-05-25  6:12 move bd_mutex to the gendisk v2 Christoph Hellwig
2021-05-25  6:12 ` [PATCH 1/8] block: split __blkdev_get Christoph Hellwig
2021-05-25  8:04   ` Hannes Reinecke
2021-05-25  6:12 ` [PATCH 2/8] block: move sync_blockdev from __blkdev_put to blkdev_put Christoph Hellwig
2021-05-25  8:05   ` Hannes Reinecke
2021-05-25  6:12 ` [PATCH 3/8] block: move bd_mutex to struct gendisk Christoph Hellwig
2021-05-25  8:06   ` Hannes Reinecke
2021-05-26  1:06   ` Ming Lei
2021-05-28  7:27   ` Roger Pau Monné
2021-05-25  6:12 ` [PATCH 4/8] block: move adjusting bd_part_count out of __blkdev_get Christoph Hellwig
2021-05-25  8:18   ` Hannes Reinecke
2021-05-26  1:59   ` Ming Lei
2021-05-25  6:12 ` [PATCH 5/8] block: split __blkdev_put Christoph Hellwig
2021-05-25  8:19   ` Hannes Reinecke
2021-05-26  2:05   ` Ming Lei
2021-05-25  6:12 ` [PATCH 6/8] block: move bd_part_count to struct gendisk Christoph Hellwig
2021-05-25  8:20   ` Hannes Reinecke
2021-05-26  2:09   ` Ming Lei
2021-05-25  6:13 ` [PATCH 7/8] block: factor out a part_devt helper Christoph Hellwig
2021-05-25  8:25   ` Hannes Reinecke
2021-05-26  2:16   ` Ming Lei
2021-05-25  6:13 ` [PATCH 8/8] block: remove bdget_disk Christoph Hellwig
2021-05-25  8:26   ` Hannes Reinecke
2021-05-26  2:24   ` Ming Lei
2021-06-01 13:48 ` move bd_mutex to the gendisk v2 Jens Axboe
  -- strict thread matches above, loose matches on Subject: below --
2021-05-12  6:18 move bd_mutex to the gendisk (resend) Christoph Hellwig
2021-05-12  6:18 ` [PATCH 6/8] block: move bd_part_count to struct gendisk Christoph Hellwig

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.