dma-mapping: provide a fallback dma_default_coherent

dma_default_coherent was decleared unconditionally at kernel/dma/mapping.c
but only decleared when any of non-coherent options is enabled in
dma-map-ops.h.

Guard the declaration in mapping.c with non-coherent options and provide
a fallback definition.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index 41bf4bdb117accace1d0d63b5680dd0c95dde61f..31f114f486c40f22c8ba65b55be3ff559ce8de0b 100644 (file)
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -269,6 +269,8 @@ static inline bool dev_is_dma_coherent(struct device *dev)
        return dev->dma_coherent;
 }
 #else
+#define dma_default_coherent true
+
 static inline bool dev_is_dma_coherent(struct device *dev)
 {
        return true;

diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 68106e3791f6c3e5da1725e719caf5337a4e72d7..80f9663ffe268fb9f64336945f4139c6b339ec5c 100644 (file)
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -17,7 +17,11 @@
 #include "debug.h"
 #include "direct.h"
 
+#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
+       defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
+       defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
 bool dma_default_coherent;
+#endif
 
 /*
  * Managed DMA API