Thread (15 messages) 15 messages, 3 authors, 2017-08-31
STALE3243d

[PATCH 04/12] x86: make dma_cache_sync a no-op

From: Christoph Hellwig <hch@lst.de>
Date: 2017-08-27 16:13:40
Also in: linux-iommu, linux-mips, linux-sh, lkml
Subsystem: the rest, x86 architecture (32-bit and 64-bit) · Maintainers: Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen

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
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