X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=mm%2Fslab.c;h=b344e67071280c9df522ef77f56ffa62ed1b4d63;hb=0452a4e5d021900b07ebdeecb9ed03b49f164f3f;hp=2e71a328aa09540a75f83ab289a3da8931920914;hpb=0b662c64840fb281e5948ab6f9d60f84817277d0;p=linux-2.6

diff --git a/mm/slab.c b/mm/slab.c
index 2e71a328aa..b344e67071 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -137,6 +137,7 @@
 
 /* Shouldn't this be in a header file somewhere? */
 #define	BYTES_PER_WORD		sizeof(void *)
+#define	REDZONE_ALIGN		max(BYTES_PER_WORD, __alignof__(unsigned long long))
 
 #ifndef cache_line_size
 #define cache_line_size()	L1_CACHE_BYTES
@@ -547,7 +548,7 @@ static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
 	if (cachep->flags & SLAB_STORE_USER)
 		return (unsigned long long *)(objp + cachep->buffer_size -
 					      sizeof(unsigned long long) -
-					      BYTES_PER_WORD);
+					      REDZONE_ALIGN);
 	return (unsigned long long *) (objp + cachep->buffer_size -
 				       sizeof(unsigned long long));
 }
@@ -774,7 +775,6 @@ static inline struct kmem_cache *__find_general_cachep(size_t size,
 	 */
 	BUG_ON(malloc_sizes[INDEX_AC].cs_cachep == NULL);
 #endif
-	WARN_ON_ONCE(size == 0);
 	while (size > csizep->cs_size)
 		csizep++;
 
@@ -2179,7 +2179,8 @@ kmem_cache_create (const char *name, size_t size, size_t align,
 	 * above the next power of two: caches with object sizes just above a
 	 * power of two have a significant amount of internal fragmentation.
 	 */
-	if (size < 4096 || fls(size - 1) == fls(size-1 + 3 * BYTES_PER_WORD))
+	if (size < 4096 || fls(size - 1) == fls(size-1 + REDZONE_ALIGN +
+						2 * sizeof(unsigned long long)))
 		flags |= SLAB_RED_ZONE | SLAB_STORE_USER;
 	if (!(flags & SLAB_DESTROY_BY_RCU))
 		flags |= SLAB_POISON;
@@ -2220,12 +2221,20 @@ kmem_cache_create (const char *name, size_t size, size_t align,
 	}
 
 	/*
-	 * Redzoning and user store require word alignment. Note this will be
-	 * overridden by architecture or caller mandated alignment if either
-	 * is greater than BYTES_PER_WORD.
+	 * Redzoning and user store require word alignment or possibly larger.
+	 * Note this will be overridden by architecture or caller mandated
+	 * alignment if either is greater than BYTES_PER_WORD.
 	 */
-	if (flags & SLAB_RED_ZONE || flags & SLAB_STORE_USER)
-		ralign = __alignof__(unsigned long long);
+	if (flags & SLAB_STORE_USER)
+		ralign = BYTES_PER_WORD;
+
+	if (flags & SLAB_RED_ZONE) {
+		ralign = REDZONE_ALIGN;
+		/* If redzoning, ensure that the second redzone is suitably
+		 * aligned, by adjusting the object size accordingly. */
+		size += REDZONE_ALIGN - 1;
+		size &= ~(REDZONE_ALIGN - 1);
+	}
 
 	/* 2) arch mandated alignment */
 	if (ralign < ARCH_SLAB_MINALIGN) {
@@ -2262,9 +2271,13 @@ kmem_cache_create (const char *name, size_t size, size_t align,
 	}
 	if (flags & SLAB_STORE_USER) {
 		/* user store requires one word storage behind the end of
-		 * the real object.
+		 * the real object. But if the second red zone needs to be
+		 * aligned to 64 bits, we must allow that much space.
 		 */
-		size += BYTES_PER_WORD;
+		if (flags & SLAB_RED_ZONE)
+			size += REDZONE_ALIGN;
+		else
+			size += BYTES_PER_WORD;
 	}
 #if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC)
 	if (size >= malloc_sizes[INDEX_L3 + 1].cs_size
@@ -3539,7 +3552,7 @@ static inline void __cache_free(struct kmem_cache *cachep, void *objp)
 	check_irq_off();
 	objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0));
 
-	if (use_alien_caches && cache_free_alien(cachep, objp))
+	if (cache_free_alien(cachep, objp))
 		return;
 
 	if (likely(ac->avail < ac->limit)) {