backing-dev: Handle class_create() failure

I hit this when we had a bug in IDR for a few days. Basically sysfs would
fail to create new inodes since it uses an IDR and therefore class_create would
fail.

While we are unlikely to see this fail we may as well handle it instead of
oopsing.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 0e8ca034770..f13e067e146 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -227,6 +227,9 @@ static struct device_attribute bdi_dev_attrs[] = {
 static __init int bdi_class_init(void)
 {
         bdi_class = class_create(THIS_MODULE, "bdi");
+        if (IS_ERR(bdi_class))
+                return PTR_ERR(bdi_class);
+
         bdi_class->dev_attrs = bdi_dev_attrs;
         bdi_debug_init();
         return 0;