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authorChristoph Lameter <clameter@sgi.com>2007-07-17 04:03:25 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-17 10:23:01 -0700
commitdfce8648d64c07eade40d456d59cb4bfcbba008c (patch)
tree7141882bd03d9848ec6299a48bc08796a8382062
parent2e443fd003d76394a8ceb78f079260478aa10710 (diff)
downloadop-kernel-dev-dfce8648d64c07eade40d456d59cb4bfcbba008c.zip
op-kernel-dev-dfce8648d64c07eade40d456d59cb4bfcbba008c.tar.gz
SLUB: do proper locking during dma slab creation
We modify the kmalloc_cache_dma[] array without proper locking. Do the proper locking and undo the dma cache creation if another processor has already created it. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/slub.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/mm/slub.c b/mm/slub.c
index 2b50b97..f93adb9 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2301,8 +2301,15 @@ static noinline struct kmem_cache *dma_kmalloc_cache(int index, gfp_t flags)
text = kasprintf(flags & ~SLUB_DMA, "kmalloc_dma-%d",
(unsigned int)realsize);
s = create_kmalloc_cache(x, text, realsize, flags);
- kmalloc_caches_dma[index] = s;
- return s;
+ down_write(&slub_lock);
+ if (!kmalloc_caches_dma[index]) {
+ kmalloc_caches_dma[index] = s;
+ up_write(&slub_lock);
+ return s;
+ }
+ up_write(&slub_lock);
+ kmem_cache_destroy(s);
+ return kmalloc_caches_dma[index];
}
#endif
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