dma-mapping: add a kconfig symbol for arch_teardown_dma_ops availability

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Catalin Marinas <catalin.marinas@arm.com> # arm64

arch/arm/Kconfig

@@ -16,6 +16,7 @@ config ARM
 	select ARCH_HAS_SET_MEMORY
 	select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
 	select ARCH_HAS_STRICT_MODULE_RWX if MMU
+	select ARCH_HAS_TEARDOWN_DMA_OPS if MMU
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
 	select ARCH_HAVE_CUSTOM_GPIO_H
 	select ARCH_HAS_GCOV_PROFILE_ALL

arch/arm/include/asm/dma-mapping.h

@@ -96,11 +96,6 @@ static inline unsigned long dma_max_pfn(struct device *dev)
 }
 #define dma_max_pfn(dev) dma_max_pfn(dev)
 
-#ifdef CONFIG_MMU
-#define arch_teardown_dma_ops arch_teardown_dma_ops
-extern void arch_teardown_dma_ops(struct device *dev);
-#endif
-
 /* do not use this function in a driver */
 static inline bool is_device_dma_coherent(struct device *dev)
 {

arch/arm64/Kconfig

@@ -29,6 +29,7 @@ config ARM64
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
 	select ARCH_HAS_SYNC_DMA_FOR_CPU
 	select ARCH_HAS_SYSCALL_WRAPPER
+	select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select ARCH_INLINE_READ_LOCK if !PREEMPT

arch/arm64/include/asm/dma-mapping.h

@@ -29,11 +29,6 @@ static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
 	return NULL;
 }
 
-#ifdef CONFIG_IOMMU_DMA
-void arch_teardown_dma_ops(struct device *dev);
-#define arch_teardown_dma_ops	arch_teardown_dma_ops
-#endif
-
 /*
  * Do not use this function in a driver, it is only provided for
  * arch/arm/mm/xen.c, which is used by arm64 as well.

include/linux/dma-mapping.h

@@ -681,9 +681,13 @@ static inline void arch_setup_dma_ops(struct device *dev, u64 dma_base,
 }
 #endif /* CONFIG_ARCH_HAS_SETUP_DMA_OPS */
 
-#ifndef arch_teardown_dma_ops
-static inline void arch_teardown_dma_ops(struct device *dev) { }
-#endif
+#ifdef CONFIG_ARCH_HAS_TEARDOWN_DMA_OPS
+void arch_teardown_dma_ops(struct device *dev);
+#else
+static inline void arch_teardown_dma_ops(struct device *dev)
+{
+}
+#endif /* CONFIG_ARCH_HAS_TEARDOWN_DMA_OPS */
 
 static inline unsigned int dma_get_max_seg_size(struct device *dev)
 {

kernel/dma/Kconfig

@@ -22,6 +22,9 @@ config HAVE_GENERIC_DMA_COHERENT
 config ARCH_HAS_SETUP_DMA_OPS
 	bool
 
+config ARCH_HAS_TEARDOWN_DMA_OPS
+	bool
+
 config ARCH_HAS_SYNC_DMA_FOR_DEVICE
 	bool