Merge branch 'stable/for-linus-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb

Pull swiotlb updates from Konrad Rzeszutek Wilk:

 - minor fixes (rate limiting), remove certain functions

 - support for DMA_ATTR_SKIP_CPU_SYNC which is an optimization
   in the DMA API

* 'stable/for-linus-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb:
  swiotlb: Minor fix-ups for DMA_ATTR_SKIP_CPU_SYNC support
  swiotlb: Add support for DMA_ATTR_SKIP_CPU_SYNC
  swiotlb-xen: Enforce return of DMA_ERROR_CODE in mapping function
  swiotlb: Drop unused functions swiotlb_map_sg and swiotlb_unmap_sg
  swiotlb: Rate-limit printing when running out of SW-IOMMU space

6 files changed, 57 insertions, 70 deletions

diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
index d062f08f5020..bd62d94f8ac5 100644
--- a/arch/arm/xen/mm.c
+++ b/arch/arm/xen/mm.c
@@ -186,7 +186,6 @@ struct dma_map_ops *xen_dma_ops;
 EXPORT_SYMBOL(xen_dma_ops);
 
 static struct dma_map_ops xen_swiotlb_dma_ops = {
-        .mapping_error = xen_swiotlb_dma_mapping_error,
         .alloc = xen_swiotlb_alloc_coherent,
         .free = xen_swiotlb_free_coherent,
         .sync_single_for_cpu = xen_swiotlb_sync_single_for_cpu,
diff --git a/arch/x86/xen/pci-swiotlb-xen.c b/arch/x86/xen/pci-swiotlb-xen.c
index 0e98e5d241d0..a9fafb5c8738 100644
--- a/arch/x86/xen/pci-swiotlb-xen.c
+++ b/arch/x86/xen/pci-swiotlb-xen.c
@@ -19,7 +19,6 @@
 int xen_swiotlb __read_mostly;
 
 static struct dma_map_ops xen_swiotlb_dma_ops = {
-        .mapping_error = xen_swiotlb_dma_mapping_error,
         .alloc = xen_swiotlb_alloc_coherent,
         .free = xen_swiotlb_free_coherent,
         .sync_single_for_cpu = xen_swiotlb_sync_single_for_cpu,
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 87e6035c9e81..478fb91e3df2 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -405,7 +405,8 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
          */
         trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force);
 
-        map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir);
+        map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir,
+                                     attrs);
         if (map == SWIOTLB_MAP_ERROR)
                 return DMA_ERROR_CODE;
 
@@ -416,11 +417,13 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
         /*
          * Ensure that the address returned is DMA'ble
          */
-        if (!dma_capable(dev, dev_addr, size)) {
-                swiotlb_tbl_unmap_single(dev, map, size, dir);
-                dev_addr = 0;
-        }
-        return dev_addr;
+        if (dma_capable(dev, dev_addr, size))
+                return dev_addr;
+
+        attrs |= DMA_ATTR_SKIP_CPU_SYNC;
+        swiotlb_tbl_unmap_single(dev, map, size, dir, attrs);
+
+        return DMA_ERROR_CODE;
 }
 EXPORT_SYMBOL_GPL(xen_swiotlb_map_page);
 
@@ -444,7 +447,7 @@ 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, paddr, size, dir);
+                swiotlb_tbl_unmap_single(hwdev, paddr, size, dir, attrs);
                 return;
         }
 
@@ -557,11 +560,12 @@ xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
                                                                  start_dma_addr,
                                                                  sg_phys(sg),
                                                                  sg->length,
-                                                                 dir);
+                                                                 dir, attrs);
                         if (map == SWIOTLB_MAP_ERROR) {
                                 dev_warn(hwdev, "swiotlb buffer is full\n");
                                 /* Don't panic here, we expect map_sg users
                                    to do proper error handling. */
+                                attrs |= DMA_ATTR_SKIP_CPU_SYNC;
                                 xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
                                                            attrs);
                                 sg_dma_len(sgl) = 0;
@@ -648,13 +652,6 @@ xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
 }
 EXPORT_SYMBOL_GPL(xen_swiotlb_sync_sg_for_device);
 
-int
-xen_swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
-{
-        return !dma_addr;
-}
-EXPORT_SYMBOL_GPL(xen_swiotlb_dma_mapping_error);
-
 /*
  * Return whether the given device DMA address mask can be supported
  * properly.  For example, if your device can only drive the low 24-bits
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 5f81f8a187f2..183f37c8a5e1 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -44,11 +44,13 @@ enum dma_sync_target {
 extern phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
                                           dma_addr_t tbl_dma_addr,
                                           phys_addr_t phys, size_t size,
-                                          enum dma_data_direction dir);
+                                          enum dma_data_direction dir,
+                                          unsigned long attrs);
 
 extern void swiotlb_tbl_unmap_single(struct device *hwdev,
                                      phys_addr_t tlb_addr,
-                                     size_t size, enum dma_data_direction dir);
+                                     size_t size, enum dma_data_direction dir,
+                                     unsigned long attrs);
 
 extern void swiotlb_tbl_sync_single(struct device *hwdev,
                                     phys_addr_t tlb_addr,
@@ -73,14 +75,6 @@ extern void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
                                unsigned long attrs);
 
 extern int
-swiotlb_map_sg(struct device *hwdev, struct scatterlist *sg, int nents,
-               enum dma_data_direction dir);
-
-extern void
-swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sg, int nents,
-                 enum dma_data_direction dir);
-
-extern int
 swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
                      enum dma_data_direction dir,
                      unsigned long attrs);
diff --git a/include/xen/swiotlb-xen.h b/include/xen/swiotlb-xen.h
index 7c35e279d1e3..a0083be5d529 100644
--- a/include/xen/swiotlb-xen.h
+++ b/include/xen/swiotlb-xen.h
@@ -51,9 +51,6 @@ xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
                                int nelems, enum dma_data_direction dir);
 
 extern int
-xen_swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr);
-
-extern int
 xen_swiotlb_dma_supported(struct device *hwdev, u64 mask);
 
 extern int
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 22e13a0e19d7..cb1b54ee8527 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -425,7 +425,8 @@ static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr,
 phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
                                    dma_addr_t tbl_dma_addr,
                                    phys_addr_t orig_addr, size_t size,
-                                   enum dma_data_direction dir)
+                                   enum dma_data_direction dir,
+                                   unsigned long attrs)
 {
         unsigned long flags;
         phys_addr_t tlb_addr;
@@ -526,7 +527,8 @@ found:
          */
         for (i = 0; i < nslots; i++)
                 io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT);
-        if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
+        if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
+            (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
                 swiotlb_bounce(orig_addr, tlb_addr, size, DMA_TO_DEVICE);
 
         return tlb_addr;
@@ -539,18 +541,20 @@ EXPORT_SYMBOL_GPL(swiotlb_tbl_map_single);
 
 static phys_addr_t
 map_single(struct device *hwdev, phys_addr_t phys, size_t size,
-           enum dma_data_direction dir)
+           enum dma_data_direction dir, unsigned long attrs)
 {
         dma_addr_t start_dma_addr = phys_to_dma(hwdev, io_tlb_start);