[PATCH] backing-dev: Handle class_create() failure

[Anton Blanchard <anton@samba.org>]

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>
---

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 0e8ca03..f13e067 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;