[PATCH] NUMA API updates

This patch three issues in NUMA API

- When 1 was passed to set_mempolicy or mbind as maxnodes argument
  get_nodes could corrupt the stack and cause a crash.  Fix that.

- Remove the restriction to do interleaving only for order 0.  Together
  with the patch that went in previously to use interleaving policy at boot
  time this should give back the original behaviour of distributing the big
  hash tables.

- Fix some bad white space in comments
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

mm/mempolicy.c

@@ -135,6 +135,10 @@ static int get_nodes(unsigned long *nodes, unsigned long __user *nmask,
 	unsigned long endmask;
 
 	--maxnode;
+	bitmap_zero(nodes, MAX_NUMNODES);
+	if (maxnode == 0 || !nmask)
+		return 0;
+
 	nlongs = BITS_TO_LONGS(maxnode);
 	if ((maxnode % BITS_PER_LONG) == 0)
 		endmask = ~0UL;
@@ -143,7 +147,7 @@ static int get_nodes(unsigned long *nodes, unsigned long __user *nmask,
 
 	/* When the user specified more nodes than supported just check
 	   if the non supported part is all zero. */
-	if (nmask && nlongs > BITS_TO_LONGS(MAX_NUMNODES)) {
+	if (nlongs > BITS_TO_LONGS(MAX_NUMNODES)) {
 		for (k = BITS_TO_LONGS(MAX_NUMNODES); k < nlongs; k++) {
 			unsigned long t;
 			if (get_user(t,  nmask + k))
@@ -158,8 +162,7 @@ static int get_nodes(unsigned long *nodes, unsigned long __user *nmask,
 		endmask = ~0UL;
 	}
 
-	bitmap_zero(nodes, MAX_NUMNODES);
-	if (nmask && copy_from_user(nodes, nmask, nlongs*sizeof(unsigned long)))
+	if (copy_from_user(nodes, nmask, nlongs*sizeof(unsigned long)))
 		return -EFAULT;
 	nodes[nlongs-1] &= endmask;
 	return mpol_check_policy(mode, nodes);
@@ -622,14 +625,14 @@ static unsigned offset_il_node(struct mempolicy *pol,
 
 /* Allocate a page in interleaved policy.
    Own path because it needs to do special accounting. */
-static struct page *alloc_page_interleave(unsigned gfp, unsigned nid)
+static struct page *alloc_page_interleave(unsigned gfp, unsigned order, unsigned nid)
 {
 	struct zonelist *zl;
 	struct page *page;
 
 	BUG_ON(!test_bit(nid, node_online_map));
 	zl = NODE_DATA(nid)->node_zonelists + (gfp & GFP_ZONEMASK);
-	page = __alloc_pages(gfp, 0, zl);
+	page = __alloc_pages(gfp, order, zl);
 	if (page && page_zone(page) == zl->zones[0]) {
 		zl->zones[0]->pageset[get_cpu()].interleave_hit++;
 		put_cpu();
@@ -677,7 +680,7 @@ alloc_page_vma(unsigned gfp, struct vm_area_struct *vma, unsigned long addr)
 			/* fall back to process interleaving */
 			nid = interleave_nodes(pol);
 		}
-		return alloc_page_interleave(gfp, nid);
+		return alloc_page_interleave(gfp, 0, nid);
 	}
 	return __alloc_pages(gfp, 0, zonelist_policy(gfp, pol));
 }
@@ -703,8 +706,8 @@ struct page *alloc_pages_current(unsigned gfp, unsigned order)
 
 	if (!pol || in_interrupt())
 		pol = &default_policy;
-	if (pol->policy == MPOL_INTERLEAVE && order == 0)
-		return alloc_page_interleave(gfp, interleave_nodes(pol));
+	if (pol->policy == MPOL_INTERLEAVE)
+		return alloc_page_interleave(gfp, order, interleave_nodes(pol));
 	return __alloc_pages(gfp, order, zonelist_policy(gfp, pol));
 }
 EXPORT_SYMBOL(alloc_pages_current);