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authorChristoph Hellwig <hch@lst.de>2018-03-28 15:35:35 +0200
committerThomas Gleixner <tglx@linutronix.de>2018-03-28 17:34:23 +0200
commite89f5b37015309a8bdf0b21d08007580b92f92a4 (patch)
tree194c925657ddd394d26ccc1ae707ffdac31c8534 /lib
parentea2301b6220117398a1de4f4bc853fbe886d5e08 (diff)
dma-mapping: Don't clear GFP_ZERO in dma_alloc_attrs
Revert the clearing of __GFP_ZERO in dma_alloc_attrs and move it to dma_direct_alloc for now. While most common architectures always zero dma cohereny allocations (and x86 did so since day one) this is not documented and at least arc and s390 do not zero without the explicit __GFP_ZERO argument. Fixes: 57bf5a8963f8 ("dma-mapping: clear harmful GFP_* flags in common code") Reported-by: Evgeniy Didin <Evgeniy.Didin@synopsys.com> Reported-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Evgeniy Didin <Evgeniy.Didin@synopsys.com> Cc: iommu@lists.linux-foundation.org Link: https://lkml.kernel.org/r/20180328133535.17302-2-hch@lst.de
Diffstat (limited to 'lib')
-rw-r--r--lib/dma-direct.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/lib/dma-direct.c b/lib/dma-direct.c
index 1277d293d4da..c0bba30fef0a 100644
--- a/lib/dma-direct.c
+++ b/lib/dma-direct.c
@@ -59,6 +59,9 @@ void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
struct page *page = NULL;
void *ret;
+ /* we always manually zero the memory once we are done: */
+ gfp &= ~__GFP_ZERO;
+
/* GFP_DMA32 and GFP_DMA are no ops without the corresponding zones: */
if (dev->coherent_dma_mask <= DMA_BIT_MASK(ARCH_ZONE_DMA_BITS))
gfp |= GFP_DMA;