[PATCH] bootmem: Make ___alloc_bootmem_node_nopanic() to be real nopanic

From: Yinghai Lu
Date: Thu Jul 12 2012 - 01:57:13 EST


after
| From 99ab7b19440a72ebdf225f99b20f8ef40decee86 Mon Sep 17 00:00:00 2001
| Date: Wed, 11 Jul 2012 14:02:53 -0700
| Subject: [PATCH] mm: sparse: fix usemap allocation above node descriptor
section

Johannes said:
| while backporting the below patch, I realised that your fix busted
| f5bf18fa22f8 again. The problem was not a panicking version on
| allocation failure but when the usemap size was too large such that
| goal + size > limit triggers the BUG_ON in the bootmem allocator. So
| we need a version that passes limit ONLY if the usemap is smaller than
| the section.

after checking the code, the name of ___alloc_bootmem_node_nopanic() does not
reflect the fact.

Make bootmem really not panic.

Hope will kill bootmem sooner.

Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx

---
mm/bootmem.c | 4 ++++
1 file changed, 4 insertions(+)

Index: linux-2.6/mm/bootmem.c
===================================================================
--- linux-2.6.orig/mm/bootmem.c
+++ linux-2.6/mm/bootmem.c
@@ -710,6 +710,10 @@ again:
if (ptr)
return ptr;

+ /* do not panic in alloc_bootmem_bdata() */
+ if (limit && goal + size > limit)
+ limit = 0;
+
ptr = alloc_bootmem_bdata(pgdat->bdata, size, align, goal, limit);
if (ptr)
return ptr;
--
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