SLUB: Do not use length parameter in slab_alloc()

We can get to the length of the object through the kmem_cache_structure.  The
additional parameter does no good and causes the compiler to generate bad
code.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/slub.c

@@ -1541,7 +1541,7 @@ static void *__slab_alloc(struct kmem_cache *s,
  * Otherwise we can simply pick the next object from the lockless free list.
  */
 static void __always_inline *slab_alloc(struct kmem_cache *s,
-		gfp_t gfpflags, int node, void *addr, int length)
+		gfp_t gfpflags, int node, void *addr)
 {
 	struct page *page;
 	void **object;
@@ -1561,23 +1561,21 @@ static void __always_inline *slab_alloc(struct kmem_cache *s,
 	local_irq_restore(flags);
 
 	if (unlikely((gfpflags & __GFP_ZERO) && object))
-		memset(object, 0, length);
+		memset(object, 0, s->objsize);
 
 	return object;
 }
 
 void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
 {
-	return slab_alloc(s, gfpflags, -1,
-			__builtin_return_address(0), s->objsize);
+	return slab_alloc(s, gfpflags, -1, __builtin_return_address(0));
 }
 EXPORT_SYMBOL(kmem_cache_alloc);
 
 #ifdef CONFIG_NUMA
 void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
 {
-	return slab_alloc(s, gfpflags, node,
-		__builtin_return_address(0), s->objsize);
+	return slab_alloc(s, gfpflags, node, __builtin_return_address(0));
 }
 EXPORT_SYMBOL(kmem_cache_alloc_node);
 #endif
@@ -2369,7 +2367,7 @@ void *__kmalloc(size_t size, gfp_t flags)
 	if (ZERO_OR_NULL_PTR(s))
 		return s;
 
-	return slab_alloc(s, flags, -1, __builtin_return_address(0), size);
+	return slab_alloc(s, flags, -1, __builtin_return_address(0));
 }
 EXPORT_SYMBOL(__kmalloc);
 
@@ -2381,7 +2379,7 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node)
 	if (ZERO_OR_NULL_PTR(s))
 		return s;
 
-	return slab_alloc(s, flags, node, __builtin_return_address(0), size);
+	return slab_alloc(s, flags, node, __builtin_return_address(0));
 }
 EXPORT_SYMBOL(__kmalloc_node);
 #endif
@@ -2712,7 +2710,7 @@ void *kmem_cache_zalloc(struct kmem_cache *s, gfp_t flags)
 {
 	void *x;
 
-	x = slab_alloc(s, flags, -1, __builtin_return_address(0), 0);
+	x = slab_alloc(s, flags, -1, __builtin_return_address(0));
 	if (x)
 		memset(x, 0, s->objsize);
 	return x;
@@ -2762,7 +2760,7 @@ void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, void *caller)
 	if (ZERO_OR_NULL_PTR(s))
 		return s;
 
-	return slab_alloc(s, gfpflags, -1, caller, size);
+	return slab_alloc(s, gfpflags, -1, caller);
 }
 
 void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
@@ -2773,7 +2771,7 @@ void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
 	if (ZERO_OR_NULL_PTR(s))
 		return s;
 
-	return slab_alloc(s, gfpflags, node, caller, size);
+	return slab_alloc(s, gfpflags, node, caller);
 }
 
 #if defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG)