ARM: dma-mapping: clean up coherent arch dma allocation

IXP23xx added support for dma_alloc_coherent() for DMA arches with an
exception in dma_alloc_coherent().  This is a subset of what goes on
in __dma_alloc(), and there is no reason why dma_alloc_writecombine()
should not be given the same treatment (except, maybe, that IXP23xx
doesn't use it.)

We can better deal with this by moving the arch_is_coherent() test
inside __dma_alloc() and killing the code duplication.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Greg Ungerer <gerg@uclinux.org>

1 files changed, 12 insertions, 19 deletions

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 19357f76ce89..3a8e527c774c 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -189,18 +189,24 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
         struct page *page;
         struct arm_vmregion *c;
 
-        if (!consistent_pte[0]) {
-                printk(KERN_ERR "%s: not initialised\n", __func__);
-                dump_stack();
-                return NULL;
-        }
-
         size = PAGE_ALIGN(size);
 
         page = __dma_alloc_buffer(dev, size, gfp);
         if (!page)
                 goto no_page;
 
+        if (arch_is_coherent()) {
+                *handle = page_to_dma(dev, page);
+                return page_address(page);
+        }
+
+        if (!consistent_pte[0]) {
+                printk(KERN_ERR "%s: not initialised\n", __func__);
+                dump_stack();
+                __dma_free_buffer(page, size);
+                return NULL;
+        }
+
         /*
          * Allocate a virtual address in the consistent mapping region.
          */
@@ -342,19 +348,6 @@ dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gf
         if (dma_alloc_from_coherent(dev, size, handle, &memory))
                 return memory;
 
-        if (arch_is_coherent()) {
-                struct page *page;
-
-                page = __dma_alloc_buffer(dev, PAGE_ALIGN(size), gfp);
-                if (!page) {
-                        *handle = ~0;
-                        return NULL;
-                }
-
-                *handle = page_to_dma(dev, page);
-                return page_address(page);
-        }
-
         return __dma_alloc(dev, size, handle, gfp,
                            pgprot_noncached(pgprot_kernel));
 }