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block: use bd_prepare_to_claim directly in the loop driver

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The arcane magic in bd_start_claiming is only needed to be able to claim
a block_device that hasn't been fully set up.  Switch the loop driver
that claims from the ioctl path with a fully set up struct block_device
to just use the much simpler bd_prepare_to_claim directly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2020-07-16 16:33:09 +02:00 committed by Jens Axboe
parent 58e46ed9cc
commit ecbe6bc000
3 changed files with 10 additions and 9 deletions
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7
drivers/block/loop.c
View file

@ -1090,11 +1090,10 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
* here to avoid changing device under exclusive owner.
*/
if (!(mode & FMODE_EXCL)) {
claimed_bdev = bd_start_claiming(bdev, loop_configure);
if (IS_ERR(claimed_bdev)) {
error = PTR_ERR(claimed_bdev);
claimed_bdev = bdev->bd_contains;
error = bd_prepare_to_claim(bdev, claimed_bdev, loop_configure);
if (error)
goto out_putf;
}
}
error = mutex_lock_killable(&loop_ctl_mutex);

9
fs/block_dev.c
View file

@ -1027,8 +1027,8 @@ static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
* RETURNS:
* 0 if @bdev can be claimed, -EBUSY otherwise.
*/
static int bd_prepare_to_claim(struct block_device *bdev,
struct block_device *whole, void *holder)
int bd_prepare_to_claim(struct block_device *bdev, struct block_device *whole,
void *holder)
{
retry:
spin_lock(&bdev_lock);
@ -1055,6 +1055,7 @@ retry:
spin_unlock(&bdev_lock);
return 0;
}
EXPORT_SYMBOL_GPL(bd_prepare_to_claim); /* only for the loop driver */
static struct gendisk *bdev_get_gendisk(struct block_device *bdev, int *partno)
{
@ -1100,7 +1101,8 @@ static struct gendisk *bdev_get_gendisk(struct block_device *bdev, int *partno)
* Pointer to the block device containing @bdev on success, ERR_PTR()
* value on failure.
*/
struct block_device *bd_start_claiming(struct block_device *bdev, void *holder)
static struct block_device *bd_start_claiming(struct block_device *bdev,
void *holder)
{
struct gendisk *disk;
struct block_device *whole;
@ -1141,7 +1143,6 @@ struct block_device *bd_start_claiming(struct block_device *bdev, void *holder)
return whole;
}
EXPORT_SYMBOL(bd_start_claiming);
static void bd_clear_claiming(struct block_device *whole, void *holder)
{

3
include/linux/blkdev.h
View file

@ -1919,7 +1919,8 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder);
struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
void *holder);
struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder);
struct block_device *bd_start_claiming(struct block_device *bdev, void *holder);
int bd_prepare_to_claim(struct block_device *bdev, struct block_device *whole,
void *holder);
void bd_abort_claiming(struct block_device *bdev, struct block_device *whole,
void *holder);
void blkdev_put(struct block_device *bdev, fmode_t mode);