diff options
| -rw-r--r-- | drivers/block/loop.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 9721d100caf1..2621ed2ce6d2 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -969,11 +969,18 @@ static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev) bd_set_size(bdev, 0); mapping_set_gfp_mask(filp->f_mapping, gfp); lo->lo_state = Lo_unbound; - fput(filp); /* This is safe: open() is still holding a reference. */ module_put(THIS_MODULE); if (max_part > 0) ioctl_by_bdev(bdev, BLKRRPART, 0); + mutex_unlock(&lo->lo_ctl_mutex); + /* + * Need not hold lo_ctl_mutex to fput backing file. + * Calling fput holding lo_ctl_mutex triggers a circular + * lock dependency possibility warning as fput can take + * bd_mutex which is usually taken before lo_ctl_mutex. + */ + fput(filp); return 0; } @@ -1191,7 +1198,7 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode, struct loop_device *lo = bdev->bd_disk->private_data; int err; - mutex_lock(&lo->lo_ctl_mutex); + mutex_lock_nested(&lo->lo_ctl_mutex, 1); switch (cmd) { case LOOP_SET_FD: err = loop_set_fd(lo, mode, bdev, arg); @@ -1200,7 +1207,10 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode, err = loop_change_fd(lo, bdev, arg); break; case LOOP_CLR_FD: + /* loop_clr_fd would have unlocked lo_ctl_mutex on success */ err = loop_clr_fd(lo, bdev); + if (!err) + goto out_unlocked; break; case LOOP_SET_STATUS: err = loop_set_status_old(lo, (struct loop_info __user *) arg); @@ -1218,6 +1228,8 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode, err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL; } mutex_unlock(&lo->lo_ctl_mutex); + +out_unlocked: return err; } |