unregister_blkdev(): do WARN_ON on failure

When unregister_blkdev() has failed, something wrong happened.  This patch
adds WARN_ON to notify of such badness.

Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/block/genhd.c b/block/genhd.c
index b321cadd6e65..7f71b2c472b8 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -120,9 +120,10 @@ int unregister_blkdev(unsigned int major, const char *name)
         for (n = &major_names[index]; *n; n = &(*n)->next)
                 if ((*n)->major == major)
                         break;
-        if (!*n || strcmp((*n)->name, name))
+        if (!*n || strcmp((*n)->name, name)) {
+                WARN_ON(1);
                 ret = -EINVAL;
-        else {
+        } else {
                 p = *n;
                 *n = p->next;
         }