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>

2 files changed, 0 insertions, 9 deletions

diff --git a/arch/mips/include/asm/dma-mapping.h b/arch/mips/include/asm/dma-mapping.h
index d724a15f0438..18fbf7af8e93 100644
--- a/arch/mips/include/asm/dma-mapping.h
+++ b/arch/mips/include/asm/dma-mapping.h
@@ -62,8 +62,6 @@ dma_set_mask(struct device *dev, u64 mask)
         return 0;
 }
 
-extern int dma_is_consistent(struct device *dev, dma_addr_t dma_addr);
-
 extern void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
                enum dma_data_direction direction);
 
diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c
index 9547bc0cf188..7ba890860d98 100644
--- a/arch/mips/mm/dma-default.c
+++ b/arch/mips/mm/dma-default.c
@@ -357,13 +357,6 @@ int dma_supported(struct device *dev, u64 mask)
 
 EXPORT_SYMBOL(dma_supported);
 
-int dma_is_consistent(struct device *dev, dma_addr_t dma_addr)
-{
-        return plat_device_is_coherent(dev);
-}
-
-EXPORT_SYMBOL(dma_is_consistent);
-
 void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
                enum dma_data_direction direction)
 {