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@xxxxxx>
---
Documentation/filesystems/locking.rst | 2 +-
block/genhd.c | 3 ++-
block/partitions/core.c | 22 +++++++---------
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, 65 insertions(+), 73 deletions(-)
diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst
index 9774e92e449fbd..1cd8090fd4b262 100644
--- a/Documentation/filesystems/locking.rst
+++ b/Documentation/filesystems/locking.rst
@@ -475,7 +475,7 @@ prototypes::
locking rules:
======================= ===================
-ops bd_mutex
+ops open_mutex
======================= ===================
open: yes
release: yes
diff --git a/block/genhd.c b/block/genhd.c
index 8c8f543572e64e..7acedbd2474381 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1379,6 +1379,7 @@ 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;
@@ -1596,7 +1597,7 @@ 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 1a7558917c47d6..60388a41ff92a3 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.
*/
void delete_partition(struct block_device *part)
@@ -308,7 +308,7 @@ 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,
@@ -440,15 +440,15 @@ 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);
}
@@ -461,8 +461,7 @@ 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)
@@ -474,8 +473,7 @@ 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;
}
@@ -490,8 +488,7 @@ 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;
@@ -504,8 +501,7 @@ 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;
}
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index a370cde3ddd49a..f5eb70a90ed067 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -651,9 +651,9 @@ 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);
@@ -746,7 +746,7 @@ 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);
@@ -1259,7 +1259,7 @@ 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
@@ -1267,10 +1267,10 @@ 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);
@@ -1297,7 +1297,7 @@ 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 e1c6798889f48a..fbab2ce7dfa1a5 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 cf8deecc39efbc..b3bf544493d340 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 419a7e8281ee3a..74c411911b6eac 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 fb7eab58cfd517..a88086d4110c24 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 a9698fba9b76ce..c93a46a38085bb 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);
blk_drop_partitions(bdev);
- 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 ed0b1bb99f0832..dc79d2e0e9dba9 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 691eef20a7ced7..4113a27ad9e72d 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -891,7 +891,6 @@ 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;
@@ -1150,7 +1149,7 @@ 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);
@@ -1195,7 +1194,7 @@ 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);
@@ -1214,7 +1213,7 @@ 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);
@@ -1226,7 +1225,7 @@ 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
@@ -1238,7 +1237,7 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)
struct gendisk *disk = bdev->bd_disk;
int ret;
- lockdep_assert_held(&bdev->bd_mutex);
+ lockdep_assert_held(&disk->open_mutex);
clear_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
@@ -1318,14 +1317,10 @@ 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 (!(disk->flags & GENHD_FL_UP) || !bdev_nr_sectors(part))
@@ -1435,7 +1430,7 @@ 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);
if (bdev_is_partition(bdev))
ret = blkdev_get_part(bdev, mode);
else
@@ -1458,7 +1453,7 @@ 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);
@@ -1467,7 +1462,7 @@ 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);
@@ -1547,7 +1542,6 @@ 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--;
@@ -1562,7 +1556,6 @@ 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);
@@ -1583,15 +1576,14 @@ 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);
@@ -1622,9 +1614,10 @@ 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);
@@ -1917,10 +1910,10 @@ 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 bc3b33efddc569..30fb9084ac145b 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1246,7 +1246,7 @@ 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 8c1baca35c160b..90b68352a26e14 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1276,9 +1276,9 @@ 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.
*/
@@ -1351,9 +1351,9 @@ 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 db026b6ec15ab7..a09660671fa47e 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 f364619092cca0..02ea04144ece7b 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;
--
2.30.1
