From: Joerg Roedel <joro@8bytes.org>
To: iommu@lists.linux-foundation.org
Cc: linux-kernel@vger.kernel.org, Joerg Roedel <jroedel@suse.de>
Subject: [PATCH] Revert "iommu/amd: Don't allocate with __GFP_ZERO in alloc_coherent"
Date: Tue, 2 Jun 2015 08:45:16 +0200 [thread overview]
Message-ID: <1433227516-30207-1-git-send-email-joro@8bytes.org> (raw)
From: Joerg Roedel <jroedel@suse.de>
This reverts commit 5fc872c7323534e8f7dc21bab635e7a9b9659e07.
The DMA-API does not strictly require that the memory
returned by dma_alloc_coherent is zeroed out. For that
another function (dma_zalloc_coherent) should be used. But
all other x86 DMA-API implementation I checked zero out the
memory, so that some drivers rely on it and break when it is
not.
It seems the (driver-)world is not yet ready for this
change, so revert it.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
drivers/iommu/amd_iommu.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index e43d489..e1c7e9e 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -2930,6 +2930,7 @@ static void *alloc_coherent(struct device *dev, size_t size,
size = PAGE_ALIGN(size);
dma_mask = dev->coherent_dma_mask;
flag &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32);
+ flag |= __GFP_ZERO;
page = alloc_pages(flag | __GFP_NOWARN, get_order(size));
if (!page) {
--
1.8.4.5
reply other threads:[~2015-06-02 6:45 UTC|newest]
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