Commit 367f7f2f authored by Joonsoo Kim's avatar Joonsoo Kim Committed by Linus Torvalds
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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: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: default avatarChristoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 833b706c

mm/slab.c

+0 −153
Original line number Diff line number Diff line
@@ -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;

}

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