dma, mm/pat: Rename dma_*_writecombine() to dma_*_wc()

Rename dma_*_writecombine() to dma_*_wc(), so that the naming
is coherent across the various write-combining APIs. Keep the
old names for compatibility for a while, these can be removed
at a later time. A guard is left to enable backporting of the
rename, and later remove of the old mapping defines seemlessly.

Build tested successfully with allmodconfig.

The following Coccinelle SmPL patch was used for this simple
transformation:

@ rename_dma_alloc_writecombine @
expression dev, size, dma_addr, gfp;
@@

-dma_alloc_writecombine(dev, size, dma_addr, gfp)
+dma_alloc_wc(dev, size, dma_addr, gfp)

@ rename_dma_free_writecombine @
expression dev, size, cpu_addr, dma_addr;
@@

-dma_free_writecombine(dev, size, cpu_addr, dma_addr)
+dma_free_wc(dev, size, cpu_addr, dma_addr)

@ rename_dma_mmap_writecombine @
expression dev, vma, cpu_addr, dma_addr, size;
@@

-dma_mmap_writecombine(dev, vma, cpu_addr, dma_addr, size)
+dma_mmap_wc(dev, vma, cpu_addr, dma_addr, size)

We also keep the old names as compatibility helpers, and
guard against their definition to make backporting easier.

Generated-by: Coccinelle SmPL
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: airlied@linux.ie
Cc: akpm@linux-foundation.org
Cc: benh@kernel.crashing.org
Cc: bhelgaas@google.com
Cc: bp@suse.de
Cc: dan.j.williams@intel.com
Cc: daniel.vetter@ffwll.ch
Cc: dhowells@redhat.com
Cc: julia.lawall@lip6.fr
Cc: konrad.wilk@oracle.com
Cc: linux-fbdev@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: luto@amacapital.net
Cc: mst@redhat.com
Cc: tomi.valkeinen@ti.com
Cc: toshi.kani@hp.com
Cc: vinod.koul@intel.com
Cc: xen-devel@lists.xensource.com
Link: http://lkml.kernel.org/r/1453516462-4844-1-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 75857cd..471e064 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -641,31 +641,40 @@
 }
 #endif /* CONFIG_HAVE_GENERIC_DMA_COHERENT */
 
-static inline void *dma_alloc_writecombine(struct device *dev, size_t size,
-					   dma_addr_t *dma_addr, gfp_t gfp)
+static inline void *dma_alloc_wc(struct device *dev, size_t size,
+				 dma_addr_t *dma_addr, gfp_t gfp)
 {
 	DEFINE_DMA_ATTRS(attrs);
 	dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
 	return dma_alloc_attrs(dev, size, dma_addr, gfp, &attrs);
 }
+#ifndef dma_alloc_writecombine
+#define dma_alloc_writecombine dma_alloc_wc
+#endif
 
-static inline void dma_free_writecombine(struct device *dev, size_t size,
-					 void *cpu_addr, dma_addr_t dma_addr)
+static inline void dma_free_wc(struct device *dev, size_t size,
+			       void *cpu_addr, dma_addr_t dma_addr)
 {
 	DEFINE_DMA_ATTRS(attrs);
 	dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
 	return dma_free_attrs(dev, size, cpu_addr, dma_addr, &attrs);
 }
+#ifndef dma_free_writecombine
+#define dma_free_writecombine dma_free_wc
+#endif
 
-static inline int dma_mmap_writecombine(struct device *dev,
-					struct vm_area_struct *vma,
-					void *cpu_addr, dma_addr_t dma_addr,
-					size_t size)
+static inline int dma_mmap_wc(struct device *dev,
+			      struct vm_area_struct *vma,
+			      void *cpu_addr, dma_addr_t dma_addr,
+			      size_t size)
 {
 	DEFINE_DMA_ATTRS(attrs);
 	dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
 	return dma_mmap_attrs(dev, vma, cpu_addr, dma_addr, size, &attrs);
 }
+#ifndef dma_mmap_writecombine
+#define dma_mmap_writecombine dma_mmap_wc
+#endif
 
 #ifdef CONFIG_NEED_DMA_MAP_STATE
 #define DEFINE_DMA_UNMAP_ADDR(ADDR_NAME)        dma_addr_t ADDR_NAME