x86: Kill bad_dma_address variable

This kills bad_dma_address variable, the old mechanism to enable
IOMMU drivers to make dma_mapping_error() work in IOMMU's
specific way.

bad_dma_address variable was introduced to enable IOMMU drivers
to make dma_mapping_error() work in IOMMU's specific way.
However, it can't handle systems that use both swiotlb and HW
IOMMU. SO we introduced dma_map_ops->mapping_error to solve that
case.

Intel VT-d, GART, and swiotlb already use
dma_map_ops->mapping_error. Calgary, AMD IOMMU, and nommu use
zero for an error dma address. This adds DMA_ERROR_CODE and
converts them to use it (as SPARC and POWER does).

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: muli@il.ibm.com
Cc: joerg.roedel@amd.com
LKML-Reference: <1258287594-8777-3-git-send-email-fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 2 deletions

diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
index 6a25d5d42836..0f6c02f3b7d4 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h
@@ -20,7 +20,8 @@
 # define ISA_DMA_BIT_MASK DMA_BIT_MASK(32)
 #endif
 
-extern dma_addr_t bad_dma_address;
+#define DMA_ERROR_CODE  0
+
 extern int iommu_merge;
 extern struct device x86_dma_fallback_dev;
 extern int panic_on_overflow;
@@ -48,7 +49,7 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
         if (ops->mapping_error)
                 return ops->mapping_error(dev, dma_addr);
 
-        return (dma_addr == bad_dma_address);
+        return (dma_addr == DMA_ERROR_CODE);
 }
 
 #define dma_alloc_noncoherent(d, s, h, f) dma_alloc_coherent(d, s, h, f)