dma-mapping: remove dma_release_declared_memory

This function is entirely unused given that declared memory is
generally provided by platform setup code.
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Documentation/DMA-API.txt

@@ -603,17 +603,6 @@ For reasons of efficiency, most platforms choose to track the declared
 region only at the granularity of a page.  For smaller allocations,
 you should use the dma_pool() API.
 
-::
-
-	void
-	dma_release_declared_memory(struct device *dev)
-
-Remove the memory region previously declared from the system.  This
-API performs *no* in-use checking for this region and will return
-unconditionally having removed all the required structures.  It is the
-driver's job to ensure that no parts of this memory region are
-currently in use.
-
 Part III - Debug drivers use of the DMA-API
 -------------------------------------------
 

include/linux/dma-mapping.h

@@ -764,7 +764,6 @@ static inline int dma_get_cache_alignment(void)
 #ifdef CONFIG_DMA_DECLARE_COHERENT
 int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
 				dma_addr_t device_addr, size_t size);
-void dma_release_declared_memory(struct device *dev);
 #else
 static inline int
 dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
@@ -772,11 +771,6 @@ dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
 {
 	return -ENOSYS;
 }
-
-static inline void
-dma_release_declared_memory(struct device *dev)
-{
-}
 #endif /* CONFIG_DMA_DECLARE_COHERENT */
 
 static inline void *dmam_alloc_coherent(struct device *dev, size_t size,

kernel/dma/coherent.c

@@ -124,17 +124,6 @@ int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
 }
 EXPORT_SYMBOL(dma_declare_coherent_memory);
 
-void dma_release_declared_memory(struct device *dev)
-{
-	struct dma_coherent_mem *mem = dev->dma_mem;
-
-	if (!mem)
-		return;
-	dma_release_coherent_memory(mem);
-	dev->dma_mem = NULL;
-}
-EXPORT_SYMBOL(dma_release_declared_memory);
-
 static void *__dma_alloc_from_coherent(struct dma_coherent_mem *mem,
 		ssize_t size, dma_addr_t *dma_handle)
 {