slab: remove a useless lockdep annotation

Now, there is no code to hold two lock simultaneously, since we don't
call slab_destroy() with holding any lock.  So, lockdep annotation is
useless now.  Remove it.

v2: don't remove BAD_ALIEN_MAGIC in this patch. It will be removed
    in the following patch.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/slab.c b/mm/slab.c
index e4dc0896b891c07ed0063417533d80641fa95e5c..630c85469164dd341fc28af80cc37aabacc15cb6 100644 (file)
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -472,139 +472,6 @@ static struct kmem_cache kmem_cache_boot = {
 
 #define BAD_ALIEN_MAGIC 0x01020304ul
 
-#ifdef CONFIG_LOCKDEP
-
-/*
- * Slab sometimes uses the kmalloc slabs to store the slab headers
- * for other slabs "off slab".
- * The locking for this is tricky in that it nests within the locks
- * of all other slabs in a few places; to deal with this special
- * locking we put on-slab caches into a separate lock-class.
- *
- * We set lock class for alien array caches which are up during init.
- * The lock annotation will be lost if all cpus of a node goes down and
- * then comes back up during hotplug
- */
-static struct lock_class_key on_slab_l3_key;
-static struct lock_class_key on_slab_alc_key;
-
-static struct lock_class_key debugobj_l3_key;
-static struct lock_class_key debugobj_alc_key;
-
-static void slab_set_lock_classes(struct kmem_cache *cachep,
-               struct lock_class_key *l3_key, struct lock_class_key *alc_key,
-               struct kmem_cache_node *n)
-{
-       struct alien_cache **alc;
-       int r;
-
-       lockdep_set_class(&n->list_lock, l3_key);
-       alc = n->alien;
-       /*
-        * FIXME: This check for BAD_ALIEN_MAGIC
-        * should go away when common slab code is taught to
-        * work even without alien caches.
-        * Currently, non NUMA code returns BAD_ALIEN_MAGIC
-        * for alloc_alien_cache,
-        */
-       if (!alc || (unsigned long)alc == BAD_ALIEN_MAGIC)
-               return;
-       for_each_node(r) {
-               if (alc[r])
-                       lockdep_set_class(&(alc[r]->lock), alc_key);
-       }
-}
-
-static void slab_set_debugobj_lock_classes_node(struct kmem_cache *cachep,
-       struct kmem_cache_node *n)
-{
-       slab_set_lock_classes(cachep, &debugobj_l3_key, &debugobj_alc_key, n);
-}
-
-static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep)
-{
-       int node;
-       struct kmem_cache_node *n;
-
-       for_each_kmem_cache_node(cachep, node, n)
-               slab_set_debugobj_lock_classes_node(cachep, n);
-}
-
-static void init_node_lock_keys(int q)
-{
-       int i;
-
-       if (slab_state < UP)
-               return;
-
-       for (i = 1; i <= KMALLOC_SHIFT_HIGH; i++) {
-               struct kmem_cache_node *n;
-               struct kmem_cache *cache = kmalloc_caches[i];
-
-               if (!cache)
-                       continue;
-
-               n = get_node(cache, q);
-               if (!n || OFF_SLAB(cache))
-                       continue;
-
-               slab_set_lock_classes(cache, &on_slab_l3_key,
-                               &on_slab_alc_key, n);
-       }
-}
-
-static void on_slab_lock_classes_node(struct kmem_cache *cachep,
-       struct kmem_cache_node *n)
-{
-       slab_set_lock_classes(cachep, &on_slab_l3_key,
-                       &on_slab_alc_key, n);
-}
-
-static inline void on_slab_lock_classes(struct kmem_cache *cachep)
-{
-       int node;
-       struct kmem_cache_node *n;
-
-       VM_BUG_ON(OFF_SLAB(cachep));
-       for_each_kmem_cache_node(cachep, node, n)
-               on_slab_lock_classes_node(cachep, n);
-}
-
-static inline void __init init_lock_keys(void)
-{
-       int node;
-
-       for_each_node(node)
-               init_node_lock_keys(node);
-}
-#else
-static void __init init_node_lock_keys(int q)
-{
-}
-
-static inline void init_lock_keys(void)
-{
-}
-
-static inline void on_slab_lock_classes(struct kmem_cache *cachep)
-{
-}
-
-static inline void on_slab_lock_classes_node(struct kmem_cache *cachep,
-       struct kmem_cache_node *n)
-{
-}
-
-static void slab_set_debugobj_lock_classes_node(struct kmem_cache *cachep,
-       struct kmem_cache_node *n)
-{
-}
-
-static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep)
-{
-}
-#endif
-
 static DEFINE_PER_CPU(struct delayed_work, slab_reap_work);
 
 static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
@@ -1348,13 +1215,7 @@ static int cpuup_prepare(long cpu)
                spin_unlock_irq(&n->list_lock);
                kfree(shared);
                free_alien_cache(alien);
-               if (cachep->flags & SLAB_DEBUG_OBJECTS)
-                       slab_set_debugobj_lock_classes_node(cachep, n);
-               else if (!OFF_SLAB(cachep) &&
-                        !(cachep->flags & SLAB_DESTROY_BY_RCU))
-                       on_slab_lock_classes_node(cachep, n);
        }
-       init_node_lock_keys(node);
 
        return 0;
 bad:
@@ -1663,9 +1524,6 @@ void __init kmem_cache_init_late(void)
                        BUG();
        mutex_unlock(&slab_mutex);
 
-       /* Annotate slab for lockdep -- annotate the malloc caches */
-       init_lock_keys();
-
        /* Done! */
        slab_state = FULL;
 
@@ -2446,17 +2304,6 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
                return err;
        }
 
-       if (flags & SLAB_DEBUG_OBJECTS) {
-               /*
-                * Would deadlock through slab_destroy()->call_rcu()->
-                * debug_object_activate()->kmem_cache_alloc().
-                */
-               WARN_ON_ONCE(flags & SLAB_DESTROY_BY_RCU);
-
-               slab_set_debugobj_lock_classes(cachep);
-       } else if (!OFF_SLAB(cachep) && !(flags & SLAB_DESTROY_BY_RCU))
-               on_slab_lock_classes(cachep);
-
        return 0;
 }