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From: Christoph Hellwig <hch@lst.de>
To: iommu@lists.linux-foundation.org
Cc: Marek Szyprowski <m.szyprowski@samsung.com>,
        Robin Murphy <robin.murphy@arm.com>, Michal Simek <monstr@monstr.eu>,
        David Howells <dhowells@redhat.com>, Guan Xuetao <gxt@mprc.pku.edu.cn>,
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        x86@kernel.org, linux-mips@linux-mips.org, linux-ia64@vger.kernel.org,
        linuxppc-dev@lists.ozlabs.org, linux-xtensa@linux-xtensa.org,
        linux-sh@vger.kernel.org, linux-kernel@vger.kernel.org,
        Christoph Hellwig <hch@lst.de>
Subject: [PATCH 04/12] x86: make dma_cache_sync a no-op
Date: Sun, 27 Aug 2017 18:10:24 +0200
Message-Id: <20170827161032.22772-5-hch@lst.de>
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x86 does not implement DMA_ATTR_NON_CONSISTENT allocations, so it doesn't
make any sense to do any work in dma_cache_sync given that it must be a
no-op when dma_alloc_attrs returns coherent memory.

Signed-off-by: Christoph Hellwig <hch@lst.de
---
 arch/x86/include/asm/dma-mapping.h | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
index 398c79889f5c..04877267ad18 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h
@@ -70,7 +70,6 @@ static inline void
 dma_cache_sync(struct device *dev, void *vaddr, size_t size,
 	enum dma_data_direction dir)
 {
-	flush_write_buffers();
 }
 
 static inline unsigned long dma_alloc_coherent_mask(struct device *dev,
-- 
2.11.0