block: fix module reference leakage from bdev_open_by_dev error path

At the time bdev_may_open() is called, module reference is grabbed
already, hence module reference should be released if bdev_may_open()
failed.

This problem is found by code review.

Fixes: ed5cc70 ("block: Add config option to not allow writing to mounted devices")
Signed-off-by: Yu Kuai <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Christian Brauner <[email protected]>

Author: YuKuai-huawei

block/bdev.c

@@ -873,7 +873,7 @@ int bdev_open(struct block_device *bdev, blk_mode_t mode, void *holder,
 		goto abort_claiming;
 	ret = -EBUSY;
 	if (!bdev_may_open(bdev, mode))
-		goto abort_claiming;
+		goto put_module;
 	if (bdev_is_partition(bdev))
 		ret = blkdev_get_part(bdev, mode);
 	else