[PATCH 02/11] x86: make dma_cache_sync a no-op

From: Christoph Hellwig
Date: Tue Oct 03 2017 - 06:47:12 EST


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@xxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
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 1387dafdba2d..c6d3367be916 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h
@@ -71,7 +71,6 @@ 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,
--
2.14.1