dm writecache: fix smatch warning about invalid return from writecache_map

There's a smatch warning "inconsistent returns '&wc->lock'" in
dm-writecache. The reason for the warning is that writecache_map()
doesn't drop the lock on the impossible path.

Fix this warning by adding wc_unlock() after the BUG statement (so
that it will be compiled-away anyway).

Fixes: df699cc16ea5e ("dm writecache: report invalid return from writecache_map helpers")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index ead008ea38f2fc52c53b82685056a5e66302cb55..03fe2c5d5e32c08e9b0d6d9c8734d7542fc67848 100644 (file)
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -1598,7 +1598,8 @@ done:
 
        default:
                BUG();
-               return -1;
+               wc_unlock(wc);
+               return DM_MAPIO_KILL;
        }
 }