ixgbe: Have the CPU take ownership of the buffers sooner

This patch makes it so that we will always have ownership of the buffers by
the time we get to ixgbe_add_rx_frag. This is necessary as I am planning to
add a copy-break to ixgbe_add_rx_frag and in order for that to function
correctly we need the CPU to have ownership of the buffer.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 9305e9a..b0020fc 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -1458,6 +1458,36 @@ static bool ixgbe_is_non_eop(struct ixgbe_ring *rx_ring,
 }
 
 /**
+ * ixgbe_dma_sync_frag - perform DMA sync for first frag of SKB
+ * @rx_ring: rx descriptor ring packet is being transacted on
+ * @skb: pointer to current skb being updated
+ *
+ * This function provides a basic DMA sync up for the first fragment of an
+ * skb.  The reason for doing this is that the first fragment cannot be
+ * unmapped until we have reached the end of packet descriptor for a buffer
+ * chain.
+ */
+static void ixgbe_dma_sync_frag(struct ixgbe_ring *rx_ring,
+                               struct sk_buff *skb)
+{
+       /* if the page was released unmap it, else just sync our portion */
+       if (unlikely(IXGBE_CB(skb)->page_released)) {
+               dma_unmap_page(rx_ring->dev, IXGBE_CB(skb)->dma,
+                              ixgbe_rx_pg_size(rx_ring), DMA_FROM_DEVICE);
+               IXGBE_CB(skb)->page_released = false;
+       } else {
+               struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[0];
+
+               dma_sync_single_range_for_cpu(rx_ring->dev,
+                                             IXGBE_CB(skb)->dma,
+                                             frag->page_offset,
+                                             ixgbe_rx_bufsz(rx_ring),
+                                             DMA_FROM_DEVICE);
+       }
+       IXGBE_CB(skb)->dma = 0;
+}
+
+/**
  * ixgbe_cleanup_headers - Correct corrupted or empty headers
  * @rx_ring: rx descriptor ring packet is being transacted on
  * @rx_desc: pointer to the EOP Rx descriptor
@@ -1484,20 +1514,6 @@ static bool ixgbe_cleanup_headers(struct ixgbe_ring *rx_ring,
        unsigned char *va;
        unsigned int pull_len;
 
-       /* if the page was released unmap it, else just sync our portion */
-       if (unlikely(IXGBE_CB(skb)->page_released)) {
-               dma_unmap_page(rx_ring->dev, IXGBE_CB(skb)->dma,
-                              ixgbe_rx_pg_size(rx_ring), DMA_FROM_DEVICE);
-               IXGBE_CB(skb)->page_released = false;
-       } else {
-               dma_sync_single_range_for_cpu(rx_ring->dev,
-                                             IXGBE_CB(skb)->dma,
-                                             frag->page_offset,
-                                             ixgbe_rx_bufsz(rx_ring),
-                                             DMA_FROM_DEVICE);
-       }
-       IXGBE_CB(skb)->dma = 0;
-
        /* verify that the packet does not have any known errors */
        if (unlikely(ixgbe_test_staterr(rx_desc,
                                        IXGBE_RXDADV_ERR_FRAME_ERR_MASK) &&
@@ -1742,8 +1758,16 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
                         * after the writeback.  Only unmap it when EOP is
                         * reached
                         */
+                       if (likely(ixgbe_test_staterr(rx_desc,
+                                                     IXGBE_RXD_STAT_EOP)))
+                               goto dma_sync;
+
                        IXGBE_CB(skb)->dma = rx_buffer->dma;
                } else {
+                       if (ixgbe_test_staterr(rx_desc, IXGBE_RXD_STAT_EOP))
+                               ixgbe_dma_sync_frag(rx_ring, skb);
+
+dma_sync:
                        /* we are reusing so sync this buffer for CPU use */
                        dma_sync_single_range_for_cpu(rx_ring->dev,
                                                      rx_buffer->dma,