Slab allocators: Replace explicit zeroing with __GFP_ZERO

kmalloc_node() and kmem_cache_alloc_node() were not available in a zeroing
variant in the past.  But with __GFP_ZERO it is possible now to do zeroing
while allocating.

Use __GFP_ZERO to remove the explicit clearing of memory via memset whereever
we can.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/block/as-iosched.c b/block/as-iosched.c
index 109e91b..3e316dd 100644
--- a/block/as-iosched.c
+++ b/block/as-iosched.c
@@ -1322,10 +1322,9 @@
 {
 	struct as_data *ad;
 
-	ad = kmalloc_node(sizeof(*ad), GFP_KERNEL, q->node);
+	ad = kmalloc_node(sizeof(*ad), GFP_KERNEL | __GFP_ZERO, q->node);
 	if (!ad)
 		return NULL;
-	memset(ad, 0, sizeof(*ad));
 
 	ad->q = q; /* Identify what queue the data belongs to */