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Commit dfce8648 authored by Christoph Lameter's avatar Christoph Lameter Committed by Linus Torvalds
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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: default avatarChristoph Lameter <clameter@sgi.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2e443fd0

mm/slub.c

+9 −2
Original line number Diff line number Diff line
@@ -2301,9 +2301,16 @@ 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);

	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



static struct kmem_cache *get_slab(size_t size, gfp_t flags)