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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 /include/linux
parentea2301b6220117398a1de4f4bc853fbe886d5e08 (diff)
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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 'include/linux')
-rw-r--r--include/linux/dma-mapping.h8
1 files changed, 2 insertions, 6 deletions
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index eb9eab4ecd6d..12fedcba9a9a 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -518,12 +518,8 @@ static inline void *dma_alloc_attrs(struct device *dev, size_t size,
if (dma_alloc_from_dev_coherent(dev, size, dma_handle, &cpu_addr))
return cpu_addr;
- /*
- * Let the implementation decide on the zone to allocate from, and
- * decide on the way of zeroing the memory given that the memory
- * returned should always be zeroed.
- */
- flag &= ~(__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM | __GFP_ZERO);
+ /* let the implementation decide on the zone to allocate from: */
+ flag &= ~(__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM);
if (!arch_dma_alloc_attrs(&dev, &flag))
return NULL;