swiotlb: rename unmap_single to do_unmap_single

Previously, swiotlb_unmap_page and swiotlb_unmap_sg were
duplicating very similar code.  Refactor that code into a
new unmap_single and unmap_single use do_unmap_single.

Note that the swiotlb_unmap_sg code was previously doing
a complicated comparison to determine if an addresses needed
to be unmapped where a simple is_swiotlb_buffer() call
would have sufficed.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Cc: jeremy@goop.org
Cc: ian.campbell@citrix.com
LKML-Reference: <1239199761-22886-6-git-send-email-galak@kernel.crashing.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 25 insertions, 17 deletions

diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index d81afab85167..2bde54a40d86 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -482,7 +482,7 @@ found:
  * dma_addr is the kernel virtual address of the bounce buffer to unmap.
  */
 static void
-unmap_single(struct device *hwdev, char *dma_addr, size_t size, int dir)
+do_unmap_single(struct device *hwdev, char *dma_addr, size_t size, int dir)
 {
         unsigned long flags;
         int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
@@ -591,7 +591,7 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
                        (unsigned long long)dev_addr);
 
                 /* DMA_TO_DEVICE to avoid memcpy in unmap_single */
-                unmap_single(hwdev, ret, size, DMA_TO_DEVICE);
+                do_unmap_single(hwdev, ret, size, DMA_TO_DEVICE);
                 return NULL;
         }
         *dma_handle = dev_addr;
@@ -608,7 +608,7 @@ swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
                 free_pages((unsigned long) vaddr, get_order(size));
         else
                 /* DMA_TO_DEVICE to avoid memcpy in unmap_single */
-                unmap_single(hwdev, vaddr, size, DMA_TO_DEVICE);
+                do_unmap_single(hwdev, vaddr, size, DMA_TO_DEVICE);
 }
 EXPORT_SYMBOL(swiotlb_free_coherent);
 
@@ -688,17 +688,29 @@ EXPORT_SYMBOL_GPL(swiotlb_map_page);
  * After this call, reads by the cpu to the buffer are guaranteed to see
  * whatever the device wrote there.
  */
-void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
-                        size_t size, enum dma_data_direction dir,
-                        struct dma_attrs *attrs)
+static void unmap_single(struct device *hwdev, dma_addr_t dev_addr,
+                         size_t size, int dir)
 {
         char *dma_addr = swiotlb_bus_to_virt(dev_addr);
 
         BUG_ON(dir == DMA_NONE);
-        if (is_swiotlb_buffer(dma_addr))
-                unmap_single(hwdev, dma_addr, size, dir);
-        else if (dir == DMA_FROM_DEVICE)
-                dma_mark_clean(dma_addr, size);
+
+        if (is_swiotlb_buffer(dma_addr)) {
+                do_unmap_single(hwdev, dma_addr, size, dir);
+                return;
+        }
+
+        if (dir != DMA_FROM_DEVICE)
+                return;
+
+        dma_mark_clean(dma_addr, size);
+}
+
+void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
+                        size_t size, enum dma_data_direction dir,
+                        struct dma_attrs *attrs)
+{
+        unmap_single(hwdev, dev_addr, size, dir);
 }
 EXPORT_SYMBOL_GPL(swiotlb_unmap_page);
 
@@ -850,13 +862,9 @@ swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
 
         BUG_ON(dir == DMA_NONE);
 
-        for_each_sg(sgl, sg, nelems, i) {
-                if (sg->dma_address != swiotlb_phys_to_bus(hwdev, sg_phys(sg)))
-                        unmap_single(hwdev, swiotlb_bus_to_virt(sg->dma_address),
-                                     sg->dma_length, dir);
-                else if (dir == DMA_FROM_DEVICE)
-                        dma_mark_clean(swiotlb_bus_to_virt(sg->dma_address), sg->dma_length);
-        }
+        for_each_sg(sgl, sg, nelems, i)
+                unmap_single(hwdev, sg->dma_address, sg->dma_length, dir);
+
 }
 EXPORT_SYMBOL(swiotlb_unmap_sg_attrs);