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block: simplify the block device claiming interface

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

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2020-11-25 21:20:08 +01:00 committed by Jens Axboe
parent a954ea8120
commit 37c3fc9abb
3 changed files with 25 additions and 44 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/block/loop.c
View File

@ -1069,7 +1069,6 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
struct file *file; struct file *file;
struct inode *inode; struct inode *inode;
struct address_space *mapping; struct address_space *mapping;
struct block_device *claimed_bdev = NULL;
int error; int error;
loff_t size; loff_t size;
bool partscan; bool partscan;
@ -1088,8 +1087,7 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
* here to avoid changing device under exclusive owner. * here to avoid changing device under exclusive owner.
*/ */
if (!(mode & FMODE_EXCL)) { if (!(mode & FMODE_EXCL)) {
claimed_bdev = bdev_whole(bdev); error = bd_prepare_to_claim(bdev, loop_configure);
error = bd_prepare_to_claim(bdev, claimed_bdev, loop_configure);
if (error) if (error)
goto out_putf; goto out_putf;
} }
@ -1176,15 +1174,15 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
mutex_unlock(&loop_ctl_mutex); mutex_unlock(&loop_ctl_mutex);
if (partscan) if (partscan)
loop_reread_partitions(lo, bdev); loop_reread_partitions(lo, bdev);
if (claimed_bdev) if (!(mode & FMODE_EXCL))
bd_abort_claiming(bdev, claimed_bdev, loop_configure); bd_abort_claiming(bdev, loop_configure);
return 0; return 0;
out_unlock: out_unlock:
mutex_unlock(&loop_ctl_mutex); mutex_unlock(&loop_ctl_mutex);
out_bdev: out_bdev:
if (claimed_bdev) if (!(mode & FMODE_EXCL))
bd_abort_claiming(bdev, claimed_bdev, loop_configure); bd_abort_claiming(bdev, loop_configure);
out_putf: out_putf:
fput(file); fput(file);
out: out:

51
fs/block_dev.c
View File

@ -110,24 +110,20 @@ EXPORT_SYMBOL(invalidate_bdev);
int truncate_bdev_range(struct block_device *bdev, fmode_t mode, int truncate_bdev_range(struct block_device *bdev, fmode_t mode,
loff_t lstart, loff_t lend) loff_t lstart, loff_t lend)
{ {
struct block_device *claimed_bdev = NULL;
int err;
/* /*
* If we don't hold exclusive handle for the device, upgrade to it * If we don't hold exclusive handle for the device, upgrade to it
* while we discard the buffer cache to avoid discarding buffers * while we discard the buffer cache to avoid discarding buffers
* under live filesystem. * under live filesystem.
*/ */
if (!(mode & FMODE_EXCL)) { if (!(mode & FMODE_EXCL)) {
claimed_bdev = bdev_whole(bdev); int err = bd_prepare_to_claim(bdev, truncate_bdev_range);
err = bd_prepare_to_claim(bdev, claimed_bdev,
truncate_bdev_range);
if (err) if (err)
return err; return err;
} }
truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend); truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend);
if (claimed_bdev) if (!(mode & FMODE_EXCL))
bd_abort_claiming(bdev, claimed_bdev, truncate_bdev_range); bd_abort_claiming(bdev, truncate_bdev_range);
return 0; return 0;
} }
EXPORT_SYMBOL(truncate_bdev_range); EXPORT_SYMBOL(truncate_bdev_range);
@ -978,7 +974,6 @@ static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
/** /**
* bd_prepare_to_claim - claim a block device * bd_prepare_to_claim - claim a block device
* @bdev: block device of interest * @bdev: block device of interest
* @whole: the whole device containing @bdev, may equal @bdev
* @holder: holder trying to claim @bdev * @holder: holder trying to claim @bdev
* *
* Claim @bdev. This function fails if @bdev is already claimed by another * Claim @bdev. This function fails if @bdev is already claimed by another
@ -988,9 +983,12 @@ static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
* RETURNS: * RETURNS:
* 0 if @bdev can be claimed, -EBUSY otherwise. * 0 if @bdev can be claimed, -EBUSY otherwise.
*/ */
int bd_prepare_to_claim(struct block_device *bdev, struct block_device *whole, int bd_prepare_to_claim(struct block_device *bdev, void *holder)
void *holder)
{ {
struct block_device *whole = bdev_whole(bdev);
if (WARN_ON_ONCE(!holder))
return -EINVAL;
retry: retry:
spin_lock(&bdev_lock); spin_lock(&bdev_lock);
/* if someone else claimed, fail */ /* if someone else claimed, fail */
@ -1030,15 +1028,15 @@ static void bd_clear_claiming(struct block_device *whole, void *holder)
/** /**
* bd_finish_claiming - finish claiming of a block device * bd_finish_claiming - finish claiming of a block device
* @bdev: block device of interest * @bdev: block device of interest
* @whole: whole block device
* @holder: holder that has claimed @bdev * @holder: holder that has claimed @bdev
* *
* Finish exclusive open of a block device. Mark the device as exlusively * Finish exclusive open of a block device. Mark the device as exlusively
* open by the holder and wake up all waiters for exclusive open to finish. * open by the holder and wake up all waiters for exclusive open to finish.
*/ */
static void bd_finish_claiming(struct block_device *bdev, static void bd_finish_claiming(struct block_device *bdev, void *holder)
struct block_device *whole, void *holder)
{ {
struct block_device *whole = bdev_whole(bdev);
spin_lock(&bdev_lock); spin_lock(&bdev_lock);
BUG_ON(!bd_may_claim(bdev, whole, holder)); BUG_ON(!bd_may_claim(bdev, whole, holder));
/* /*
@ -1063,11 +1061,10 @@ static void bd_finish_claiming(struct block_device *bdev,
* also used when exclusive open is not actually desired and we just needed * also used when exclusive open is not actually desired and we just needed
* to block other exclusive openers for a while. * to block other exclusive openers for a while.
*/ */
void bd_abort_claiming(struct block_device *bdev, struct block_device *whole, void bd_abort_claiming(struct block_device *bdev, void *holder)
void *holder)
{ {
spin_lock(&bdev_lock); spin_lock(&bdev_lock);
bd_clear_claiming(whole, holder); bd_clear_claiming(bdev_whole(bdev), holder);
spin_unlock(&bdev_lock); spin_unlock(&bdev_lock);
} }
EXPORT_SYMBOL(bd_abort_claiming); EXPORT_SYMBOL(bd_abort_claiming);
@ -1487,7 +1484,6 @@ void blkdev_put_no_open(struct block_device *bdev)
*/ */
struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
{ {
struct block_device *claiming;
bool unblock_events = true; bool unblock_events = true;
struct block_device *bdev; struct block_device *bdev;
struct gendisk *disk; struct gendisk *disk;
@ -1510,15 +1506,9 @@ retry:
disk = bdev->bd_disk; disk = bdev->bd_disk;
if (mode & FMODE_EXCL) { if (mode & FMODE_EXCL) {
WARN_ON_ONCE(!holder); ret = bd_prepare_to_claim(bdev, holder);
ret = -ENOMEM;
claiming = bdget_disk(disk, 0);
if (!claiming)
goto put_blkdev;
ret = bd_prepare_to_claim(bdev, claiming, holder);
if (ret) if (ret)
goto put_claiming; goto put_blkdev;
} }
disk_block_events(disk); disk_block_events(disk);
@ -1528,7 +1518,7 @@ retry:
if (ret) if (ret)
goto abort_claiming; goto abort_claiming;
if (mode & FMODE_EXCL) { if (mode & FMODE_EXCL) {
bd_finish_claiming(bdev, claiming, holder); bd_finish_claiming(bdev, holder);
/* /*
* Block event polling for write claims if requested. Any write * Block event polling for write claims if requested. Any write
@ -1547,18 +1537,13 @@ retry:
if (unblock_events) if (unblock_events)
disk_unblock_events(disk); disk_unblock_events(disk);
if (mode & FMODE_EXCL)
bdput(claiming);
return bdev; return bdev;
abort_claiming: abort_claiming:
if (mode & FMODE_EXCL) if (mode & FMODE_EXCL)
bd_abort_claiming(bdev, claiming, holder); bd_abort_claiming(bdev, holder);
mutex_unlock(&bdev->bd_mutex); mutex_unlock(&bdev->bd_mutex);
disk_unblock_events(disk); disk_unblock_events(disk);
put_claiming:
if (mode & FMODE_EXCL)
bdput(claiming);
put_blkdev: put_blkdev:
blkdev_put_no_open(bdev); blkdev_put_no_open(bdev);
if (ret == -ERESTARTSYS) if (ret == -ERESTARTSYS)

6
include/linux/blkdev.h
View File

@ -1988,10 +1988,8 @@ void blkdev_show(struct seq_file *seqf, off_t offset);
struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
void *holder); void *holder);
struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder); struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder);
int bd_prepare_to_claim(struct block_device *bdev, struct block_device *whole, int bd_prepare_to_claim(struct block_device *bdev, void *holder);
void *holder); void bd_abort_claiming(struct block_device *bdev, void *holder);
void bd_abort_claiming(struct block_device *bdev, struct block_device *whole,
void *holder);
void blkdev_put(struct block_device *bdev, fmode_t mode); void blkdev_put(struct block_device *bdev, fmode_t mode);
/* just for blk-cgroup, don't use elsewhere */ /* just for blk-cgroup, don't use elsewhere */