[PATCH] slab : allow SLAB_RED_ZONE and SLAB_STORE_USER to work on arm

From: Matthieu CASTET
Date: Tue Oct 16 2012 - 07:17:23 EST


From: Matthieu CASTET <castet.matthieu@xxxxxxx>

on cortexA8 (omap3) ralign is 64 and __alignof__(unsigned long long) is 8.
So we always disable debug.

This patch is based on 5c5e3b33b7cb959a401f823707bee006caadd76e, but fix
case were align < sizeof(unsigned long long).

Signed-off-by: Matthieu Castet <matthieu.castet@xxxxxxxxxx>
CC: Russell King <rmk@xxxxxxxxxxxxxxxx>
CC: Pekka Enberg <penberg@xxxxxxxxxxxxxx>
---
mm/slab.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index c685475..8427901 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2462,9 +2462,6 @@ __kmem_cache_create (const char *name, size_t size, size_t align,
if (ralign < align) {
ralign = align;
}
- /* disable debug if necessary */
- if (ralign > __alignof__(unsigned long long))
- flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
/*
* 4) Store it.
*/
@@ -2491,8 +2488,9 @@ __kmem_cache_create (const char *name, size_t size, size_t align,
*/
if (flags & SLAB_RED_ZONE) {
/* add space for red zone words */
- cachep->obj_offset += sizeof(unsigned long long);
- size += 2 * sizeof(unsigned long long);
+ int offset = max(align, sizeof(unsigned long long));
+ cachep->obj_offset += offset;
+ size += offset + sizeof(unsigned long long);
}
if (flags & SLAB_STORE_USER) {
/* user store requires one word storage behind the end of
--
1.7.10.4

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