This patch fixes duplicated memset that is 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 <[email protected]> Cc: Marek Szyprowski <[email protected]> Cc: Konrad Rzeszutek Wilk <[email protected]> Cc: David Woodhouse <[email protected]> Cc: Don Dutile <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Andi Kleen <[email protected]> Cc: [email protected] Cc: [email protected] --- 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 f15bf8d..a25e202 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 */ -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
