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>
---
 include/linux/dma-map-ops.h | 1 +
 kernel/dma/mapping.c        | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index 41bf4bdb117a..0a1aaf7163b3 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -269,6 +269,7 @@ 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 68106e3791f6..80f9663ffe26 100644
--- 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
-- 
2.37.1 (Apple Git-137.1)

On Thu, Feb 23, 2023 at 11:36:41AM +0000, Jiaxun Yang wrote:
> 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.

Overly lone line here.

>  }
>  #else
> +#define dma_default_coherent true
>  static inline bool dev_is_dma_coherent(struct device *dev)

Please keep an empty line before the function declaration.