[PATCH 3.16 306/328] dm cache: destroy migration_cache if cache target registration failed

[Ben Hutchings]

3.16.62-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Shenghui Wang <shh...@foxmail.com>

commit c7cd55504a5b0fc826a2cd9540845979d24ae542 upstream.

Commit 7e6358d244e47 ("dm: fix various targets to dm_register_target
after module __init resources created") inadvertently introduced this
bug when it moved dm_register_target() after the call to KMEM_CACHE().

Fixes: 7e6358d244e47 ("dm: fix various targets to dm_register_target after 
module __init resources created")
Signed-off-by: Shenghui Wang <shh...@foxmail.com>
Signed-off-by: Mike Snitzer <snit...@redhat.com>
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
 drivers/md/dm-cache-target.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -3109,14 +3109,13 @@ static int __init dm_cache_init(void)
        int r;
 
        migration_cache = KMEM_CACHE(dm_cache_migration, 0);
-       if (!migration_cache) {
-               dm_unregister_target(&cache_target);
+       if (!migration_cache)
                return -ENOMEM;
-       }
 
        r = dm_register_target(&cache_target);
        if (r) {
                DMERR("cache target registration failed: %d", r);
+               kmem_cache_destroy(migration_cache);
                return r;
        }