From 3671c4ced7e0807937993f7a988c883afa4e41bb Mon Sep 17 00:00:00 2001 From: Akinobu Mita Date: Thu, 22 May 2014 10:42:46 +1000 Subject: [PATCH] arch/x86/kernel/pci-dma.c: avoid duplicated memset in dma_generic_alloc_coherent() Fix a duplicated memset that was introduced by the patch x86-make-dma_alloc_coherent-return-zeroed-memory-if-cma-is-enabled.patch in -mm tree, and this change should be folded into it. If dma_generic_alloc_coherent() is called with __GFP_ZERO, it does a duplicated memset to the memory area allocated by alloc_pages_node() with __GFP_ZERO. This change fixes that inefficiency by clearing __GFP_ZERO bit in gfp flages before calling alloc_pages_node(). Note that dma_generic_alloc_coherent() always returns zeroed memory. Signed-off-by: Akinobu Mita Cc: Marek Szyprowski Cc: Konrad Rzeszutek Wilk Cc: David Woodhouse Cc: Don Dutile Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Andi Kleen Signed-off-by: Andrew Morton --- arch/x86/kernel/pci-dma.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c index a0ffe44325bf..e5f4e9629e61 100644 --- a/arch/x86/kernel/pci-dma.c +++ b/arch/x86/kernel/pci-dma.c @@ -97,6 +97,7 @@ void *dma_generic_alloc_coherent(struct device *dev, size_t size, dma_mask = dma_alloc_coherent_mask(dev, flag); + flag &= ~__GFP_ZERO; again: page = NULL; /* CMA can be used only in the context which permits sleeping */ -- 2.39.5