Re: [PATCH] mm: CONFIG_HAVE_MEMBLOCK_NODE -> CONFIG_HAVE_MEMBLOCK_NODE_MAP

[Rabin Vincent <rabin@rab.in>]

On Fri, Jun 29, 2012 at 01:21:39PM -0700, Tejun Heo wrote:
> This probably has been doing something weird to 32bit machines w/
> memory hotplug configured (which probably are extremely rare).  It
> would be nice if the patch description explained what behavior it
> actually fixes.  How did you find this?  From config check util or did
> you actually see something broken?

Neither, I just noticed it while debugging some unrelated problems.  The
arch I work on (ARM) doesn't even select this so I don't have any
observed behaviour to describe -- I'll just add a paraphrase of your
statement about who's affected to the patch description.

8<--------------------
>From 38c7a50331efa83e4d07cbd1d6364d62e4448482 Mon Sep 17 00:00:00 2001
From: Rabin Vincent <rabin@rab.in>
Date: Sat, 30 Jun 2012 01:17:45 +0530
Subject: [PATCHv2] mm: CONFIG_HAVE_MEMBLOCK_NODE -> CONFIG_HAVE_MEMBLOCK_NODE_MAP

0ee332c14518699 ("memblock: Kill early_node_map[]") wanted to replace
CONFIG_ARCH_POPULATES_NODE_MAP with CONFIG_HAVE_MEMBLOCK_NODE_MAP but
ended up replacing one occurence with a reference to the non-existent
symbol CONFIG_HAVE_MEMBLOCK_NODE.

The resulting omission of code would probably have been causing problems
to 32-bit machines with memory hotplug.

Cc: stable@vger.kernel.org
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Rabin Vincent <rabin@rab.in>
---
 include/linux/mmzone.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 2427706..1d0a9a3 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -773,7 +773,7 @@ extern int movable_zone;
 
 static inline int zone_movable_is_highmem(void)
 {
-#if defined(CONFIG_HIGHMEM) && defined(CONFIG_HAVE_MEMBLOCK_NODE)
+#if defined(CONFIG_HIGHMEM) && defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP)
 	return movable_zone == ZONE_HIGHMEM;
 #else
 	return 0;
-- 
1.7.9.5