mm/sl[aou]b: Move sysfs_slab_add to common

Simplify locking by moving the slab_add_sysfs after all locks have been
dropped. Eases the upcoming move to provide sysfs support for all
allocators.

Reviewed-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
diff --git a/mm/slab_common.c b/mm/slab_common.c
index adc42b0..4f72208 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -152,6 +152,14 @@
 		return NULL;
 	}
 
+	if (s->refcount == 1) {
+		err = sysfs_slab_add(s);
+		if (err)
+			printk(KERN_WARNING "kmem_cache_create(%s) failed to"
+				" create sysfs entry. Error %d\n",
+					name, err);
+	}
+
 	return s;
 }
 EXPORT_SYMBOL(kmem_cache_create);