These are used in order to block loop_exit() while holding backing files. Cc: Jan Kara <jack@xxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> --- drivers/block/loop.c | 16 ++++------------ 1 file changed, 4 insertions(+), 12 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 150012ffb387..3a87c33df2ec 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -959,9 +959,6 @@ static int loop_configure(struct loop_device *lo, fmode_t mode, return -EBADF; is_loop = is_loop_device(file); - /* This is safe, since we have a reference from open(). */ - __module_get(THIS_MODULE); - /* * If we don't hold exclusive handle for the device, upgrade to it * here to avoid changing device under exclusive owner. @@ -1027,6 +1024,8 @@ static int loop_configure(struct loop_device *lo, fmode_t mode, lo->use_dio = lo->lo_flags & LO_FLAGS_DIRECT_IO; lo->lo_device = bdev; lo->lo_backing_file = file; + /* Block loop_exit() while holding backing file. */ + __module_get(THIS_MODULE); lo->old_gfp_mask = mapping_gfp_mask(mapping); mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); @@ -1077,8 +1076,6 @@ static int loop_configure(struct loop_device *lo, fmode_t mode, bd_abort_claiming(bdev, loop_configure); out_putf: fput(file); - /* This is safe: open() is still holding a reference. */ - module_put(THIS_MODULE); return error; } @@ -1144,8 +1141,6 @@ static void __loop_clr_fd(struct loop_device *lo, bool release) /* let user-space know about this change */ kobject_uevent(&disk_to_dev(lo->lo_disk)->kobj, KOBJ_CHANGE); mapping_set_gfp_mask(filp->f_mapping, gfp); - /* This is safe: open() is still holding a reference. */ - module_put(THIS_MODULE); blk_mq_unfreeze_queue(lo->lo_queue); disk_force_media_change(lo->lo_disk, DISK_EVENT_MEDIA_CHANGE); @@ -1185,12 +1180,9 @@ static void __loop_clr_fd(struct loop_device *lo, bool release) lo->lo_state = Lo_unbound; mutex_unlock(&lo->lo_mutex); - /* - * 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 open_mutex which is usually taken before lo_mutex. - */ + /* Release backing file and unblock loop_exit(). */ fput(filp); + module_put(THIS_MODULE); } static int loop_clr_fd(struct loop_device *lo) -- 2.32.0
