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>

diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
index 581f44b..b1da9f4 100644 (file)
--- 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 725fe2d..fbd493e 100644 (file)
--- 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;