From: Prarit Bhargava <prarit@redhat.com>
Subject: [RHEL5.1 PATCH] BZ 228564: memory-less node support
Date: Thu, 3 May 2007 12:02:22 -0400
Bugzilla: 228564
Message-Id: <20070503160222.8591.96821.sendpatchset@prarit.boston.redhat.com>
Changelog: [mm] memory-less node support


Backport of

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=8af5e2eb3cc4450ffba9496c875beac41bf4f4f8

Resolves 228564.

Compile & boot tested only.

I was unable to test this as I do not have access to a system with memoryless
nodes.  However, I was able to get a sign off on the patch by Christoph Lameter
and as noted, the patch is upstream.


diff -urNp -X linux-2.6.18.x86_64/Documentation/dontdiff linux-2.6.18.x86_64.orig/mm/mempolicy.c linux-2.6.18.x86_64/mm/mempolicy.c
--- linux-2.6.18.x86_64.orig/mm/mempolicy.c	2007-04-04 09:01:08.000000000 -0400
+++ linux-2.6.18.x86_64/mm/mempolicy.c	2007-04-04 09:37:44.000000000 -0400
@@ -142,7 +142,7 @@ static struct zonelist *bind_zonelist(no
 	max = 1 + MAX_NR_ZONES * nodes_weight(*nodes);
 	zl = kmalloc(sizeof(struct zone *) * max, GFP_KERNEL);
 	if (!zl)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 	num = 0;
 	/* First put in the highest zones from all nodes, then all the next 
 	   lower zones etc. Avoid empty zones because the memory allocator
@@ -155,6 +155,10 @@ static struct zonelist *bind_zonelist(no
 				zl->zones[num++] = z;
 		}
 	}
+	if (num == 0) {
+		kfree(zl);
+		return ERR_PTR(-EINVAL);
+	}
 	zl->zones[num] = NULL;
 	return zl;
 }
@@ -186,9 +190,10 @@ static struct mempolicy *mpol_new(int mo
 		break;
 	case MPOL_BIND:
 		policy->v.zonelist = bind_zonelist(nodes);
-		if (policy->v.zonelist == NULL) {
+		if (IS_ERR(policy->v.zonelist)) {
+			void *error_code = policy->v.zonelist;
 			kmem_cache_free(policy_cache, policy);
-			return ERR_PTR(-ENOMEM);
+			return error_code;
 		}
 		break;
 	}
@@ -1655,7 +1660,7 @@ void mpol_rebind_policy(struct mempolicy
 		 * then zonelist_policy() will "FALL THROUGH" to MPOL_DEFAULT.
 		 */
 
-		if (zonelist) {
+		if (!IS_ERR(zonelist)) {
 			/* Good - got mem - substitute new zonelist */
 			kfree(pol->v.zonelist);
 			pol->v.zonelist = zonelist;