Merge tag 'stable/for-linus-3.8-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb

Pull swiotlb update from Konrad Rzeszutek Wilk:
 "Feature:
   - Use dma addresses instead of the virt_to_phys and vice versa
     functions.

  Remove the multitude of phys_to_virt/virt_to_phys calls and instead
  operate on the physical addresses instead of virtual in many of the
  internal functions.  This does provide a speed up in interrupt
  handlers that do DMA operations and use SWIOTLB."

* tag 'stable/for-linus-3.8-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb:
  swiotlb: Do not export swiotlb_bounce since there are no external consumers
  swiotlb: Use physical addresses instead of virtual in swiotlb_tbl_sync_single
  swiotlb: Use physical addresses for swiotlb_tbl_unmap_single
  swiotlb: Return physical addresses when calling swiotlb_tbl_map_single
  swiotlb: Make io_tlb_overflow_buffer a physical address
  swiotlb: Make io_tlb_start a physical address instead of a virtual one
  swiotlb: Make io_tlb_end a physical address instead of a virtual one

1 files changed, 12 insertions, 13 deletions

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 58db6df866ef..af47e7594460 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -338,9 +338,8 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
                                 enum dma_data_direction dir,
                                 struct dma_attrs *attrs)
 {
-        phys_addr_t phys = page_to_phys(page) + offset;
+        phys_addr_t map, phys = page_to_phys(page) + offset;
         dma_addr_t dev_addr = xen_phys_to_bus(phys);
-        void *map;
 
         BUG_ON(dir == DMA_NONE);
         /*
@@ -356,10 +355,10 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
          * Oh well, have to allocate and map a bounce buffer.
          */
         map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir);
-        if (!map)
+        if (map == SWIOTLB_MAP_ERROR)
                 return DMA_ERROR_CODE;
 
-        dev_addr = xen_virt_to_bus(map);
+        dev_addr = xen_phys_to_bus(map);
 
         /*
          * Ensure that the address returned is DMA'ble
@@ -389,7 +388,7 @@ static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr,
 
         /* NOTE: We use dev_addr here, not paddr! */
         if (is_xen_swiotlb_buffer(dev_addr)) {
-                swiotlb_tbl_unmap_single(hwdev, phys_to_virt(paddr), size, dir);
+                swiotlb_tbl_unmap_single(hwdev, paddr, size, dir);
                 return;
         }
 
@@ -434,8 +433,7 @@ xen_swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,
 
         /* NOTE: We use dev_addr here, not paddr! */
         if (is_xen_swiotlb_buffer(dev_addr)) {
-                swiotlb_tbl_sync_single(hwdev, phys_to_virt(paddr), size, dir,
-                                       target);
+                swiotlb_tbl_sync_single(hwdev, paddr, size, dir, target);
                 return;
         }
 
@@ -494,11 +492,12 @@ xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
                 if (swiotlb_force ||
                     !dma_capable(hwdev, dev_addr, sg->length) ||
                     range_straddles_page_boundary(paddr, sg->length)) {
-                        void *map = swiotlb_tbl_map_single(hwdev,
-                                                           start_dma_addr,
-                                                           sg_phys(sg),
-                                                           sg->length, dir);
-                        if (!map) {
+                        phys_addr_t map = swiotlb_tbl_map_single(hwdev,
+                                                                 start_dma_addr,
+                                                                 sg_phys(sg),
+                                                                 sg->length,
+                                                                 dir);
+                        if (map == SWIOTLB_MAP_ERROR) {
                                 /* Don't panic here, we expect map_sg users
                                    to do proper error handling. */
                                 xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
@@ -506,7 +505,7 @@ xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
                                 sgl[0].dma_length = 0;
                                 return DMA_ERROR_CODE;
                         }
-                        sg->dma_address = xen_virt_to_bus(map);
+                        sg->dma_address = xen_phys_to_bus(map);
                 } else
                         sg->dma_address = dev_addr;
                 sg->dma_length = sg->length;