The patch titled
kmalloc: return NULL instead of link failure
has been added to the -mm tree. Its filename is
kmalloc-return-null-instead-of-link-failure.patch
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Subject: kmalloc: return NULL instead of link failure
From: Jeff Mahoney <jeffm@xxxxxxxx>
The SLAB kmalloc with a constant value isn't consistent with the other
implementations because it bails out with __you_cannot_kmalloc_that_much
rather than returning NULL and properly allowing the caller to fall back
to vmalloc or take other action. This doesn't happen with a non-constant
value or with SLOB or SLUB.
Starting with 2.6.28, I've been seeing build failures on s390x. This is
due to init_section_page_cgroup trying to allocate 2.5MB when the max size
for a kmalloc on s390x is 2MB.
It's failing because the value is constant. The workarounds at the call
size are ugly and the caller shouldn't have to change behavior depending
on what the backend of the API is.
So, this patch eliminates the link failure and returns NULL like the other
implementations.
Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxxxxxx>
Cc: Matt Mackall <mpm@xxxxxxxxxxx>
Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxx> [2.6.28.x]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/slab_def.h | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)
diff -puN include/linux/slab_def.h~kmalloc-return-null-instead-of-link-failure include/linux/slab_def.h
--- a/include/linux/slab_def.h~kmalloc-return-null-instead-of-link-failure
+++ a/include/linux/slab_def.h
@@ -143,10 +143,7 @@ static __always_inline void *kmalloc(siz
i++;
#include <linux/kmalloc_sizes.h>
#undef CACHE
- {
- extern void __you_cannot_kmalloc_that_much(void);
- __you_cannot_kmalloc_that_much();
- }
+ return NULL;
found:
#ifdef CONFIG_ZONE_DMA
if (flags & GFP_DMA)
@@ -201,10 +198,7 @@ static __always_inline void *kmalloc_nod
i++;
#include <linux/kmalloc_sizes.h>
#undef CACHE
- {
- extern void __you_cannot_kmalloc_that_much(void);
- __you_cannot_kmalloc_that_much();
- }
+ return NULL;
found:
#ifdef CONFIG_ZONE_DMA
if (flags & GFP_DMA)
_
Patches currently in -mm which might be from jeffm@xxxxxxxx are
origin.patch
x86-define-arch_want_frame_pointers.patch
x86-define-arch_want_frame_pointers-fix.patch
kmalloc-return-null-instead-of-link-failure.patch
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