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Date: Fri, 24 Aug 2012 16:17:29 +0000
From: Christoph Lameter <cl@linux.com>
Subject: C13 [10/14] Do slab aliasing call from common code
References: <20120824160903.168122683@linux.com>
Sender: owner-linux-mm@kvack.org
List-ID: <linux-mm.kvack.org>
To: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <js1304@gmail.com>, Glauber Costa <glommer@parallels.com>, linux-mm@kvack.org, David Rientjes <rientjes@google.com>

The slab aliasing logic causes some strange contortions in
slub. So add a call to deal with aliases to slab_common.c
but disable it for other slab allocators by providng stubs
that fail to create aliases.

Full general support for aliases will require additional
cleanup passes and more standardization of fields in
kmem_cache.

V1->V2:
	- Move kstrdup before kmem_cache_alias invocation.
	(JoonSoo Kim)

Signed-off-by: Christoph Lameter <cl@linux.com>
---
 mm/slab.h        |   10 ++++++++++
 mm/slab_common.c |    4 ++++
 mm/slub.c        |   15 +++++++++++----
 3 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/mm/slab.h b/mm/slab.h
index c4f9a36..84c28f4 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -36,6 +36,16 @@ extern struct kmem_cache *kmem_cache;
 struct kmem_cache *__kmem_cache_create(const char *name, size_t size,
 	size_t align, unsigned long flags, void (*ctor)(void *));
 
+#ifdef CONFIG_SLUB
+struct kmem_cache *__kmem_cache_alias(const char *name, size_t size,
+	size_t align, unsigned long flags, void (*ctor)(void *));
+#else
+static inline struct kmem_cache *__kmem_cache_alias(const char *name, size_t size,
+	size_t align, unsigned long flags, void (*ctor)(void *))
+{ return NULL; }
+#endif
+
+
 int __kmem_cache_shutdown(struct kmem_cache *);
 
 #endif
diff --git a/mm/slab_common.c b/mm/slab_common.c
index cb3b2c1..e5cd47f 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -115,6 +115,10 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size, size_t align
 		goto out_locked;
 	}
 
+	s = __kmem_cache_alias(name, size, align, flags, ctor);
+	if (s)
+		goto out_locked;
+
 	s = __kmem_cache_create(n, size, align, flags, ctor);
 
 	if (s) {
diff --git a/mm/slub.c b/mm/slub.c
index 09ea157..5751f30 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3708,7 +3708,7 @@ void __init kmem_cache_init(void)
 		slub_max_order = 0;
 
 	kmem_size = offsetof(struct kmem_cache, node) +
-				nr_node_ids * sizeof(struct kmem_cache_node *);
+			nr_node_ids * sizeof(struct kmem_cache_node *);
 
 	/* Allocate two kmem_caches from the page allocator */
 	kmalloc_size = ALIGN(kmem_size, cache_line_size());
@@ -3922,7 +3922,7 @@ static struct kmem_cache *find_mergeable(size_t size,
 	return NULL;
 }
 
-struct kmem_cache *__kmem_cache_create(const char *name, size_t size,
+struct kmem_cache *__kmem_cache_alias(const char *name, size_t size,
 		size_t align, unsigned long flags, void (*ctor)(void *))
 {
 	struct kmem_cache *s;
@@ -3939,11 +3939,18 @@ struct kmem_cache *__kmem_cache_create(const char *name, size_t size,
 
 		if (sysfs_slab_alias(s, name)) {
 			s->refcount--;
-			return NULL;
+			s = NULL;
 		}
-		return s;
 	}
 
+	return s;
+}
+
+struct kmem_cache *__kmem_cache_create(const char *name, size_t size,
+		size_t align, unsigned long flags, void (*ctor)(void *))
+{
+	struct kmem_cache *s;
+
 	s = kmem_cache_alloc(kmem_cache, GFP_KERNEL);
 	if (s) {
 		if (kmem_cache_open(s, name,
-- 
1.7.9.5


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