From dfce8648d64c07eade40d456d59cb4bfcbba008c Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Tue, 17 Jul 2007 04:03:25 -0700 Subject: 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/slub.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 2b50b97a0fc..f93adb915c0 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 -- cgit v1.2.3