Imported Upstream version 16.11.1

[deb_dpdk.git] / drivers / net / virtio / virtio_rxtx.c

diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index 22d97a4..a33ef1a 100644 (file)
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -258,6 +258,12 @@ tx_offload_enabled(struct virtio_hw *hw)
                vtpci_with_feature(hw, VIRTIO_NET_F_HOST_TSO6);
 }
 
+/* avoid write operation when necessary, to lessen cache issues */
+#define ASSIGN_UNLESS_EQUAL(var, val) do {     \
+       if ((var) != (val))                     \
+               (var) = (val);                  \
+} while (0)
+
 static inline void
 virtqueue_enqueue_xmit(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
                       uint16_t needed, int use_indirect, int can_push)
@@ -286,8 +292,14 @@ virtqueue_enqueue_xmit(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
                hdr = (struct virtio_net_hdr *)
                        rte_pktmbuf_prepend(cookie, head_size);
                /* if offload disabled, it is not zeroed below, do it now */
-               if (offload == 0)
-                       memset(hdr, 0, head_size);
+               if (offload == 0) {
+                       ASSIGN_UNLESS_EQUAL(hdr->csum_start, 0);
+                       ASSIGN_UNLESS_EQUAL(hdr->csum_offset, 0);
+                       ASSIGN_UNLESS_EQUAL(hdr->flags, 0);
+                       ASSIGN_UNLESS_EQUAL(hdr->gso_type, 0);
+                       ASSIGN_UNLESS_EQUAL(hdr->gso_size, 0);
+                       ASSIGN_UNLESS_EQUAL(hdr->hdr_len, 0);
+               }
        } else if (use_indirect) {
                /* setup tx ring slot to point to indirect
                 * descriptor list stored in reserved region.
@@ -337,9 +349,9 @@ virtqueue_enqueue_xmit(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
                        break;
 
                default:
-                       hdr->csum_start = 0;
-                       hdr->csum_offset = 0;
-                       hdr->flags = 0;
+                       ASSIGN_UNLESS_EQUAL(hdr->csum_start, 0);
+                       ASSIGN_UNLESS_EQUAL(hdr->csum_offset, 0);
+                       ASSIGN_UNLESS_EQUAL(hdr->flags, 0);
                        break;
                }
 
@@ -355,9 +367,9 @@ virtqueue_enqueue_xmit(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
                                cookie->l3_len +
                                cookie->l4_len;
                } else {
-                       hdr->gso_type = 0;
-                       hdr->gso_size = 0;
-                       hdr->hdr_len = 0;
+                       ASSIGN_UNLESS_EQUAL(hdr->gso_type, 0);
+                       ASSIGN_UNLESS_EQUAL(hdr->gso_size, 0);
+                       ASSIGN_UNLESS_EQUAL(hdr->hdr_len, 0);
                }
        }