slub: separate out sysfs_slab_release() from sysfs_slab_remove()

Separate out slub sysfs removal and release, and call the former earlier
from __kmem_cache_shutdown().  There's no reason to defer sysfs removal
through RCU and this will later allow us to remove sysfs files way
earlier during memory cgroup offline instead of release.

Link: http://lkml.kernel.org/r/20170117235411.9408-3-tj@kernel.org
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 13 insertions, 5 deletions

diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 75f56c2ef2d4..07ef550c6627 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -113,9 +113,9 @@ struct kmem_cache {
 
 #ifdef CONFIG_SYSFS
 #define SLAB_SUPPORTS_SYSFS
-void sysfs_slab_remove(struct kmem_cache *);
+void sysfs_slab_release(struct kmem_cache *);
 #else
-static inline void sysfs_slab_remove(struct kmem_cache *s)
+static inline void sysfs_slab_release(struct kmem_cache *s)
 {
 }
 #endif
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 4a999d749d2b..e6311b2dbba6 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -483,7 +483,7 @@ static void release_caches(struct list_head *release, bool need_rcu_barrier)
 
         list_for_each_entry_safe(s, s2, release, list) {
 #ifdef SLAB_SUPPORTS_SYSFS
-                sysfs_slab_remove(s);
+                sysfs_slab_release(s);
 #else
                 slab_kmem_cache_release(s);
 #endif
diff --git a/mm/slub.c b/mm/slub.c
index 6de08005d9cd..caac5456f0ec 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -214,11 +214,13 @@ enum track_item { TRACK_ALLOC, TRACK_FREE };
 static int sysfs_slab_add(struct kmem_cache *);
 static int sysfs_slab_alias(struct kmem_cache *, const char *);
 static void memcg_propagate_slab_attrs(struct kmem_cache *s);
+static void sysfs_slab_remove(struct kmem_cache *s);
 #else
 static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
 static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
                                                         { return 0; }
 static inline void memcg_propagate_slab_attrs(struct kmem_cache *s) { }
+static inline void sysfs_slab_remove(struct kmem_cache *s) { }
 #endif
 
 static inline void stat(const struct kmem_cache *s, enum stat_item si)
@@ -3687,6 +3689,7 @@ int __kmem_cache_shutdown(struct kmem_cache *s)
                 if (n->nr_partial || slabs_node(s, node))
                         return 1;
         }
+        sysfs_slab_remove(s);
         return 0;
 }
 
@@ -5637,7 +5640,7 @@ out_del_kobj:
         goto out;
 }
 
-void sysfs_slab_remove(struct kmem_cache *s)
+static void sysfs_slab_remove(struct kmem_cache *s)
 {
         if (slab_state < FULL)
                 /*
@@ -5651,7 +5654,12 @@ void sysfs_slab_remove(struct kmem_cache *s)
 #endif
         kobject_uevent(&s->kobj, KOBJ_REMOVE);
         kobject_del(&s->kobj);
-        kobject_put(&s->kobj);
+}
+
+void sysfs_slab_release(struct kmem_cache *s)
+{
+        if (slab_state >= FULL)
+                kobject_put(&s->kobj);
 }
 
 /*