dma-mapping: remove dma_is_consistent API

Architectures implement dma_is_consistent() in different ways (some
misinterpret the definition of API in DMA-API.txt).  So it hasn't been so
useful for drivers.  We have only one user of the API in tree.  Unlikely
out-of-tree drivers use the API.

Even if we fix dma_is_consistent() in some architectures, it doesn't look
useful at all.  It was invented long ago for some old systems that can't
allocate coherent memory at all.  It's better to export only APIs that are
definitely necessary for drivers.

Let's remove this API.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 1 deletions

diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
index f9c67e8..d4c419f 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h
@@ -54,7 +54,6 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 
 #define dma_alloc_noncoherent(d, s, h, f) dma_alloc_coherent(d, s, h, f)
 #define dma_free_noncoherent(d, s, v, h) dma_free_coherent(d, s, v, h)
-#define dma_is_consistent(d, h)	(1)
 
 extern int dma_supported(struct device *hwdev, u64 mask);
 extern int dma_set_mask(struct device *dev, u64 mask);