ixgbevf: add support for DMA_ATTR_SKIP_CPU_SYNC/WEAK_ORDERING

Based on commit 5be5955425c2
("igb: update driver to make use of DMA_ATTR_SKIP_CPU_SYNC")
and
commit 7bd175928280 ("igb: Add support for DMA_ATTR_WEAK_ORDERING")

Convert the calls to dma_map/unmap_page() to the attributes version
and add DMA_ATTR_SKIP_CPU_SYNC/WEAK_ORDERING which should help
improve performance on some platforms.

Move sync_for_cpu call before we perform a prefetch to avoid
invalidating the first 128 bytes of the packet on architectures where
that call may invalidate the cache.

Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

2 files changed, 38 insertions, 22 deletions

diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
index 581f44bbd7b3..b1da9f41c1dc 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
@@ -260,6 +260,9 @@ static inline void ixgbevf_write_tail(struct ixgbevf_ring *ring, u32 value)
 #define MIN_MSIX_Q_VECTORS      1
 #define MIN_MSIX_COUNT          (MIN_MSIX_Q_VECTORS + NON_Q_VECTORS)
 
+#define IXGBEVF_RX_DMA_ATTR \
+        (DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_WEAK_ORDERING)
+
 /* board specific private data structure */
 struct ixgbevf_adapter {
         /* this field must be first, see ixgbevf_process_skb_fields */
diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index 725fe2dca868..fbd493efd14e 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -595,8 +595,8 @@ static bool ixgbevf_alloc_mapped_page(struct ixgbevf_ring *rx_ring,
         }
 
         /* map page for use */
-        dma = dma_map_page(rx_ring->dev, page, 0,
-                           PAGE_SIZE, DMA_FROM_DEVICE);
+        dma = dma_map_page_attrs(rx_ring->dev, page, 0, PAGE_SIZE,
+                                 DMA_FROM_DEVICE, IXGBEVF_RX_DMA_ATTR);
 
         /* if mapping failed free memory back to system since
          * there isn't much point in holding memory we can't use
@@ -639,6 +639,12 @@ static void ixgbevf_alloc_rx_buffers(struct ixgbevf_ring *rx_ring,
                 if (!ixgbevf_alloc_mapped_page(rx_ring, bi))
                         break;
 
+                /* sync the buffer for use by the device */
+                dma_sync_single_range_for_device(rx_ring->dev, bi->dma,
+                                                 bi->page_offset,
+                                                 IXGBEVF_RX_BUFSZ,
+                                                 DMA_FROM_DEVICE);
+
                 /* Refresh the desc even if pkt_addr didn't change
                  * because each write-back erases this info.
                  */
@@ -741,12 +747,6 @@ static void ixgbevf_reuse_rx_page(struct ixgbevf_ring *rx_ring,
         new_buff->page = old_buff->page;
         new_buff->dma = old_buff->dma;
         new_buff->page_offset = old_buff->page_offset;
-
-        /* sync the buffer for use by the device */
-        dma_sync_single_range_for_device(rx_ring->dev, new_buff->dma,
-                                         new_buff->page_offset,
-                                         IXGBEVF_RX_BUFSZ,
-                                         DMA_FROM_DEVICE);
 }
 
 static inline bool ixgbevf_page_is_reserved(struct page *page)
@@ -862,6 +862,13 @@ static struct sk_buff *ixgbevf_fetch_rx_buffer(struct ixgbevf_ring *rx_ring,
         page = rx_buffer->page;
         prefetchw(page);
 
+        /* we are reusing so sync this buffer for CPU use */
+        dma_sync_single_range_for_cpu(rx_ring->dev,
+                                      rx_buffer->dma,
+                                      rx_buffer->page_offset,
+                                      size,
+                                      DMA_FROM_DEVICE);
+
         if (likely(!skb)) {
                 void *page_addr = page_address(page) +
                                   rx_buffer->page_offset;
@@ -887,21 +894,15 @@ static struct sk_buff *ixgbevf_fetch_rx_buffer(struct ixgbevf_ring *rx_ring,
                 prefetchw(skb->data);
         }
 
-        /* we are reusing so sync this buffer for CPU use */
-        dma_sync_single_range_for_cpu(rx_ring->dev,
-                                      rx_buffer->dma,
-                                      rx_buffer->page_offset,
-                                      size,
-                                      DMA_FROM_DEVICE);
-
         /* pull page into skb */
         if (ixgbevf_add_rx_frag(rx_ring, rx_buffer, size, rx_desc, skb)) {
                 /* hand second half of page back to the ring */
                 ixgbevf_reuse_rx_page(rx_ring, rx_buffer);
         } else {
                 /* we are not reusing the buffer so unmap it */
-                dma_unmap_page(rx_ring->dev, rx_buffer->dma,
-                               PAGE_SIZE, DMA_FROM_DEVICE);
+                dma_unmap_page_attrs(rx_ring->dev, rx_buffer->dma,
+                                     PAGE_SIZE, DMA_FROM_DEVICE,
+                                     IXGBEVF_RX_DMA_ATTR);
         }
 
         /* clear contents of buffer_info */
@@ -2116,7 +2117,6 @@ void ixgbevf_up(struct ixgbevf_adapter *adapter)
  **/
 static void ixgbevf_clean_rx_ring(struct ixgbevf_ring *rx_ring)
 {
-        struct device *dev = rx_ring->dev;
         unsigned long size;
         unsigned int i;
 
@@ -2135,10 +2135,23 @@ static void ixgbevf_clean_rx_ring(struct ixgbevf_ring *rx_ring)
                 struct ixgbevf_rx_buffer *rx_buffer;
 
                 rx_buffer = &rx_ring->rx_buffer_info[i];
-                if (rx_buffer->dma)
-                        dma_unmap_page(dev, rx_buffer->dma,
-                                       PAGE_SIZE, DMA_FROM_DEVICE);
-                rx_buffer->dma = 0;
+
+                /* Invalidate cache lines that may have been written to by
+                 * device so that we avoid corrupting memory.
+                 */
+                dma_sync_single_range_for_cpu(rx_ring->dev,
+                                              rx_buffer->dma,
+                                              rx_buffer->page_offset,
+                                              IXGBEVF_RX_BUFSZ,
+                                              DMA_FROM_DEVICE);
+
+                /* free resources associated with mapping */
+                dma_unmap_page_attrs(rx_ring->dev,
+                                     rx_buffer->dma,
+                                     PAGE_SIZE,
+                                     DMA_FROM_DEVICE,
+                                     IXGBEVF_RX_DMA_ATTR);
+
                 if (rx_buffer->page)
                         __free_page(rx_buffer->page);
                 rx_buffer->page = NULL;