loop: mutex already unlocked in loop_clr_fd()

mount/1865 is trying to release lock (&lo->lo_ctl_mutex) at:
but there are no more locks to release!

mutex is already unlocked in loop_clr_fd(), we should not
try to unlock it in lo_release() again.

Signed-off-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 40b17d3b55a1..ddae80825899 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1431,6 +1431,7 @@ static int lo_open(struct block_device *bdev, fmode_t mode)
 static int lo_release(struct gendisk *disk, fmode_t mode)
 {
         struct loop_device *lo = disk->private_data;
+        int err;
 
         mutex_lock(&lo->lo_ctl_mutex);
 
@@ -1442,7 +1443,9 @@ static int lo_release(struct gendisk *disk, fmode_t mode)
                  * In autoclear mode, stop the loop thread
                  * and remove configuration after last close.
                  */
-                loop_clr_fd(lo, NULL);
+                err = loop_clr_fd(lo, NULL);
+                if (!err)
+                        goto out_unlocked;
         } else {
                 /*
                  * Otherwise keep thread (if running) and config,
@@ -1453,7 +1456,7 @@ static int lo_release(struct gendisk *disk, fmode_t mode)
 
 out:
         mutex_unlock(&lo->lo_ctl_mutex);
-
+out_unlocked:
         return 0;
 }