x86: isolate coherent mapping functions

i386 implements the declare coherent memory API, and x86_64 does not
it is reflected in pieces of dma_alloc_coherent and dma_free_coherent.
Those pieces are isolated in separate functions, that are declared
as empty macros in x86_64. This way we can make the code the same.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 45 insertions, 17 deletions

diff --git a/arch/x86/kernel/pci-dma_32.c b/arch/x86/kernel/pci-dma_32.c
index 818d95efc3cb..78c7640252a4 100644
--- a/arch/x86/kernel/pci-dma_32.c
+++ b/arch/x86/kernel/pci-dma_32.c
@@ -18,27 +18,50 @@
 dma_addr_t bad_dma_address __read_mostly = 0x0;
 EXPORT_SYMBOL(bad_dma_address);
 
-void *dma_alloc_coherent(struct device *dev, size_t size,
-                           dma_addr_t *dma_handle, gfp_t gfp)
+static int dma_alloc_from_coherent_mem(struct device *dev, ssize_t size,
+                                       dma_addr_t *dma_handle, void **ret)
 {
-        void *ret;
         struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
         int order = get_order(size);
-        /* ignore region specifiers */
-        gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
 
         if (mem) {
                 int page = bitmap_find_free_region(mem->bitmap, mem->size,
                                                      order);
                 if (page >= 0) {
                         *dma_handle = mem->device_base + (page << PAGE_SHIFT);
-                        ret = mem->virt_base + (page << PAGE_SHIFT);
-                        memset(ret, 0, size);
-                        return ret;
+                        *ret = mem->virt_base + (page << PAGE_SHIFT);
+                        memset(*ret, 0, size);
                 }
                 if (mem->flags & DMA_MEMORY_EXCLUSIVE)
-                        return NULL;
+                        *ret = NULL;
+        }
+        return (mem != NULL);
+}
+
+static int dma_release_coherent(struct device *dev, int order, void *vaddr)
+{
+        struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
+
+        if (mem && vaddr >= mem->virt_base && vaddr <
+                   (mem->virt_base + (mem->size << PAGE_SHIFT))) {
+                int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
+
+                bitmap_release_region(mem->bitmap, page, order);
+                return 1;
         }
+        return 0;
+}
+
+void *dma_alloc_coherent(struct device *dev, size_t size,
+                           dma_addr_t *dma_handle, gfp_t gfp)
+{
+        void *ret = NULL;
+        int order = get_order(size);
+        /* ignore region specifiers */
+        gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
+
+        if (dma_alloc_from_coherent_mem(dev, size, dma_handle, &ret))
+                return ret;
 
         if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
                 gfp |= GFP_DMA;
@@ -56,15 +79,11 @@ EXPORT_SYMBOL(dma_alloc_coherent);
 void dma_free_coherent(struct device *dev, size_t size,
                          void *vaddr, dma_addr_t dma_handle)
 {
-        struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
         int order = get_order(size);
 
         WARN_ON(irqs_disabled());       /* for portability */
-        if (mem && vaddr >= mem->virt_base && vaddr < (mem->virt_base + (mem->size << PAGE_SHIFT))) {
-                int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
-
-                bitmap_release_region(mem->bitmap, page, order);
-        } else
-                free_pages((unsigned long)vaddr, order);
+        if (dma_release_coherent(dev, order, vaddr))
+                return;
+        free_pages((unsigned long)vaddr, order);
 }
 EXPORT_SYMBOL(dma_free_coherent);
diff --git a/arch/x86/kernel/pci-dma_64.c b/arch/x86/kernel/pci-dma_64.c
index e7d45cf82251..6eacd58e451b 100644
--- a/arch/x86/kernel/pci-dma_64.c
+++ b/arch/x86/kernel/pci-dma_64.c
@@ -39,6 +39,8 @@ dma_alloc_pages(struct device *dev, gfp_t gfp, unsigned order)
         return page ? page_address(page) : NULL;
 }
 
+#define dma_alloc_from_coherent_mem(dev, size, handle, ret) (0)
+#define dma_release_coherent(dev, order, vaddr) (0)
 /*
  * Allocate memory for a coherent mapping.
  */
@@ -50,6 +52,10 @@ dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle,
         unsigned long dma_mask = 0;
         u64 bus;
 
+
+        if (dma_alloc_from_coherent_mem(dev, size, dma_handle, &memory))
+                return memory;
+
         if (!dev)
                 dev = &fallback_dev;
         dma_mask = dev->coherent_dma_mask;
@@ -141,9 +147,12 @@ EXPORT_SYMBOL(dma_alloc_coherent);
 void dma_free_coherent(struct device *dev, size_t size,
                          void *vaddr, dma_addr_t bus)
 {
+        int order = get_order(size);
         WARN_ON(irqs_disabled());       /* for portability */
+        if (dma_release_coherent(dev, order, vaddr))
+                return;
         if (dma_ops->unmap_single)
                 dma_ops->unmap_single(dev, bus, size, 0);
-        free_pages((unsigned long)vaddr, get_order(size));
+        free_pages((unsigned long)vaddr, order);
 }
 EXPORT_SYMBOL(dma_free_coherent);