Revert "loop: Fix double mutex_unlock(&loop_ctl_mutex) in loop_control_ioctl()"

This reverts commit d2762edcb6af99fc9322bab0b1d4e71a427760e8 which is
commit 628bd85947091830a8c4872adfd5ed1d515a9cf2 upstream.

It does not work properly in the 4.14.y tree and causes more problems
than it fixes, so revert it.

Reported-by: Thomas Lindroth <thomas.lindroth@gmail.com>
Reported-by: Jan Kara <jack@suse.cz>
Cc: syzbot <syzbot+c0138741c2290fc5e63f@syzkaller.appspotmail.com>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 7910dd8b1d3a5abb12d7c63f1c4d2d1bc5b2d11c..ceb62579eb21e695f70615f7c4ace1336f71d2e8 100644 (file)
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1996,10 +1996,12 @@ static long loop_control_ioctl(struct file *file, unsigned int cmd,
                        break;
                if (lo->lo_state != Lo_unbound) {
                        ret = -EBUSY;
+                       mutex_unlock(&loop_ctl_mutex);
                        break;
                }
                if (atomic_read(&lo->lo_refcnt) > 0) {
                        ret = -EBUSY;
+                       mutex_unlock(&loop_ctl_mutex);
                        break;
                }
                lo->lo_disk->private_data = NULL;