2 files changed, 64 insertions, 138 deletions

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 877baf2a94f4..5dcb06fe9667 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -391,13 +391,8 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
         if (dma_capable(dev, dev_addr, size) &&
             !range_straddles_page_boundary(phys, size) &&
                 !xen_arch_need_swiotlb(dev, phys, dev_addr) &&
-                (swiotlb_force != SWIOTLB_FORCE)) {
-                /* we are not interested in the dma_addr returned by
-                 * xen_dma_map_page, only in the potential cache flushes executed
-                 * by the function. */
-                xen_dma_map_page(dev, page, dev_addr, offset, size, dir, attrs);
-                return dev_addr;
-        }
+                swiotlb_force != SWIOTLB_FORCE)
+                goto done;
 
         /*
          * Oh well, have to allocate and map a bounce buffer.
@@ -410,19 +405,25 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
                 return DMA_MAPPING_ERROR;
 
         dev_addr = xen_phys_to_bus(map);
-        xen_dma_map_page(dev, pfn_to_page(map >> PAGE_SHIFT),
-                                        dev_addr, map & ~PAGE_MASK, size, dir, attrs);
 
         /*
          * Ensure that the address returned is DMA'ble
          */
-        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);
+        if (unlikely(!dma_capable(dev, dev_addr, size))) {
+                swiotlb_tbl_unmap_single(dev, map, size, dir,
+                                attrs | DMA_ATTR_SKIP_CPU_SYNC);
+                return DMA_MAPPING_ERROR;
+        }
 
-        return DMA_MAPPING_ERROR;
+        page = pfn_to_page(map >> PAGE_SHIFT);
+        offset = map & ~PAGE_MASK;
+done:
+        /*
+         * we are not interested in the dma_addr returned by xen_dma_map_page,
+         * only in the potential cache flushes executed by the function.
+         */
+        xen_dma_map_page(dev, page, dev_addr, offset, size, dir, attrs);
+        return dev_addr;
 }
 
 /*
@@ -455,48 +456,28 @@ static void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
         xen_unmap_single(hwdev, dev_addr, size, dir, attrs);
 }
 
-/*
- * Make physical memory consistent for a single streaming mode DMA translation
- * after a transfer.
- *
- * If you perform a xen_swiotlb_map_page() but wish to interrogate the buffer
- * using the cpu, yet do not wish to teardown the dma mapping, you must
- * call this function before doing so.  At the next point you give the dma
- * address back to the card, you must first perform a
- * xen_swiotlb_dma_sync_for_device, and then the device again owns the buffer
- */
 static void
-xen_swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,
-                        size_t size, enum dma_data_direction dir,
-                        enum dma_sync_target target)
+xen_swiotlb_sync_single_for_cpu(struct device *dev, dma_addr_t dma_addr,
+                size_t size, enum dma_data_direction dir)
 {
-        phys_addr_t paddr = xen_bus_to_phys(dev_addr);
-
-        BUG_ON(dir == DMA_NONE);
-
-        if (target == SYNC_FOR_CPU)
-                xen_dma_sync_single_for_cpu(hwdev, dev_addr, size, dir);
+        phys_addr_t paddr = xen_bus_to_phys(dma_addr);
 
-        /* NOTE: We use dev_addr here, not paddr! */
-        if (is_xen_swiotlb_buffer(dev_addr))
-                swiotlb_tbl_sync_single(hwdev, paddr, size, dir, target);
+        xen_dma_sync_single_for_cpu(dev, dma_addr, size, dir);
 
-        if (target == SYNC_FOR_DEVICE)
-                xen_dma_sync_single_for_device(hwdev, dev_addr, size, dir);
+        if (is_xen_swiotlb_buffer(dma_addr))
+                swiotlb_tbl_sync_single(dev, paddr, size, dir, SYNC_FOR_CPU);
 }
 
-void
-xen_swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
-                                size_t size, enum dma_data_direction dir)
+static void
+xen_swiotlb_sync_single_for_device(struct device *dev, dma_addr_t dma_addr,
+                size_t size, enum dma_data_direction dir)
 {
-        xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU);
-}
+        phys_addr_t paddr = xen_bus_to_phys(dma_addr);
 
-void
-xen_swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
-                                   size_t size, enum dma_data_direction dir)
-{
-        xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE);
+        if (is_xen_swiotlb_buffer(dma_addr))
+                swiotlb_tbl_sync_single(dev, paddr, size, dir, SYNC_FOR_DEVICE);
+
+        xen_dma_sync_single_for_device(dev, dma_addr, size, dir);
 }
 
 /*
@@ -504,9 +485,8 @@ xen_swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
  * concerning calls here are the same as for swiotlb_unmap_page() above.
  */
 static void
-xen_swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
-                           int nelems, enum dma_data_direction dir,
-                           unsigned long attrs)
+xen_swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
+                enum dma_data_direction dir, unsigned long attrs)
 {
         struct scatterlist *sg;
         int i;
@@ -518,26 +498,9 @@ xen_swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
 
 }
 
-/*
- * Map a set of buffers described by scatterlist in streaming mode for DMA.
- * This is the scatter-gather version of the above xen_swiotlb_map_page
- * interface.  Here the scatter gather list elements are each tagged with the
- * appropriate dma address and length.  They are obtained via
- * sg_dma_{address,length}(SG).
- *
- * NOTE: An implementation may be able to use a smaller number of
- *       DMA address/length pairs than there are SG table elements.
- *       (for example via virtual mapping capabilities)
- *       The routine returns the number of addr/length pairs actually
- *       used, at most nents.
- *
- * Device ownership issues as mentioned above for xen_swiotlb_map_page are the
- * same here.
- */
 static int
-xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
-                         int nelems, enum dma_data_direction dir,
-                         unsigned long attrs)
+xen_swiotlb_map_sg(struct device *dev, struct scatterlist *sgl, int nelems,
+                enum dma_data_direction dir, unsigned long attrs)
 {
         struct scatterlist *sg;
         int i;
@@ -545,85 +508,44 @@ xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
         BUG_ON(dir == DMA_NONE);
 
         for_each_sg(sgl, sg, nelems, i) {
-                phys_addr_t paddr = sg_phys(sg);
-                dma_addr_t dev_addr = xen_phys_to_bus(paddr);
-
-                if (swiotlb_force == SWIOTLB_FORCE ||
-                    xen_arch_need_swiotlb(hwdev, paddr, dev_addr) ||
-                    !dma_capable(hwdev, dev_addr, sg->length) ||
-                    range_straddles_page_boundary(paddr, sg->length)) {
-                        phys_addr_t map = swiotlb_tbl_map_single(hwdev,
-                                                                 start_dma_addr,
-                                                                 sg_phys(sg),
-                                                                 sg->length,
-                                                                 dir, attrs);
-                        if (map == DMA_MAPPING_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;
-                                return 0;
-                        }
-                        dev_addr = xen_phys_to_bus(map);
-                        xen_dma_map_page(hwdev, pfn_to_page(map >> PAGE_SHIFT),
-                                                dev_addr,
-                                                map & ~PAGE_MASK,
-                                                sg->length,
-                                                dir,
-                                                attrs);
-                        sg->dma_address = dev_addr;
-                } else {
-                        /* we are not interested in the dma_addr returned by
-                         * xen_dma_map_page, only in the potential cache flushes executed
-                         * by the function. */
-                        xen_dma_map_page(hwdev, pfn_to_page(paddr >> PAGE_SHIFT),
-                                                dev_addr,
-                                                paddr & ~PAGE_MASK,
-                                                sg->length,
-                                                dir,
-                                                attrs);
-                        sg->dma_address = dev_addr;
-                }
+                sg->dma_address = xen_swiotlb_map_page(dev, sg_page(sg),
+                                sg->offset, sg->length, dir, attrs);
+                if (sg->dma_address == DMA_MAPPING_ERROR)
+                        goto out_unmap;
                 sg_dma_len(sg) = sg->length;
         }
+
         return nelems;
+out_unmap:
+        xen_swiotlb_unmap_sg(dev, sgl, i, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC);
+        sg_dma_len(sgl) = 0;
+        return 0;
 }
 
-/*
- * Make physical memory consistent for a set of streaming mode DMA translations
- * after a transfer.
- *
- * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules
- * and usage.
- */
 static void
-xen_swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
-                    int nelems, enum dma_data_direction dir,
-                    enum dma_sync_target target)
+xen_swiotlb_sync_sg_for_cpu(struct device *dev, struct scatterlist *sgl,
+                            int nelems, enum dma_data_direction dir)
 {
         struct scatterlist *sg;
         int i;
 
-        for_each_sg(sgl, sg, nelems, i)
-                xen_swiotlb_sync_single(hwdev, sg->dma_address,
-                                        sg_dma_len(sg), dir, target);
-}
-
-static void
-xen_swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
-                            int nelems, enum dma_data_direction dir)
-{
-        xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU);
+        for_each_sg(sgl, sg, nelems, i) {
+                xen_swiotlb_sync_single_for_cpu(dev, sg->dma_address,
+                                sg->length, dir);
+        }
 }
 
 static void
-xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
+xen_swiotlb_sync_sg_for_device(struct device *dev, struct scatterlist *sgl,
                                int nelems, enum dma_data_direction dir)
 {
-        xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE);
+        struct scatterlist *sg;
+        int i;
+
+        for_each_sg(sgl, sg, nelems, i) {
+                xen_swiotlb_sync_single_for_device(dev, sg->dma_address,
+                                sg->length, dir);
+        }
 }
 
 /*
@@ -690,8 +612,8 @@ const struct dma_map_ops xen_swiotlb_dma_ops = {
         .sync_single_for_device = xen_swiotlb_sync_single_for_device,
         .sync_sg_for_cpu = xen_swiotlb_sync_sg_for_cpu,
         .sync_sg_for_device = xen_swiotlb_sync_sg_for_device,
-        .map_sg = xen_swiotlb_map_sg_attrs,
-        .unmap_sg = xen_swiotlb_unmap_sg_attrs,
+        .map_sg = xen_swiotlb_map_sg,
+        .unmap_sg = xen_swiotlb_unmap_sg,
         .map_page = xen_swiotlb_map_page,
         .unmap_page = xen_swiotlb_unmap_page,
         .dma_supported = xen_swiotlb_dma_supported,
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 53012db1e53c..6f7619c1f877 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -452,6 +452,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
         unsigned long mask;
         unsigned long offset_slots;
         unsigned long max_slots;
+        unsigned long tmp_io_tlb_used;
 
         if (no_iotlb_memory)
                 panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
@@ -538,9 +539,12 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
         } while (index != wrap);
 
 not_found:
+        tmp_io_tlb_used = io_tlb_used;
+
         spin_unlock_irqrestore(&io_tlb_lock, flags);
         if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit())
-                dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes)\n", size);
+                dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n",
+                         size, io_tlb_nslabs, tmp_io_tlb_used);
         return DMA_MAPPING_ERROR;
 found:
         io_tlb_used += nslots;