[dpdk-dev] [PATCH v2 2/4] examples/vhost: remove unnecessary pseudo checksum calc

[Yuanhan Liu]

For checksum offloading only case, the TCP/IP stack would
have calculated the pseudo checksum. Therefore, we don't
need to re-calculate it again here; remove it.

Signed-off-by: Yuanhan Liu <yuanhan.liu at linux.intel.com>
---
 examples/vhost/main.c | 41 ++++++-----------------------------------
 1 file changed, 6 insertions(+), 35 deletions(-)

diff --git a/examples/vhost/main.c b/examples/vhost/main.c
index a45cddb..ceabbce 100644
--- a/examples/vhost/main.c
+++ b/examples/vhost/main.c
@@ -52,8 +52,6 @@
 #include <rte_virtio_net.h>
 #include <rte_ip.h>
 #include <rte_tcp.h>
-#include <rte_udp.h>
-#include <rte_sctp.h>

 #include "main.h"

@@ -1161,42 +1159,15 @@ static void virtio_tx_offload(struct rte_mbuf *m)
        void *l3_hdr;
        struct ipv4_hdr *ipv4_hdr = NULL;
        struct tcp_hdr *tcp_hdr = NULL;
-       struct udp_hdr *udp_hdr = NULL;
-       struct sctp_hdr *sctp_hdr = NULL;
        struct ether_hdr *eth_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *);

        l3_hdr = (char *)eth_hdr + m->l2_len;

-       if (m->tso_segsz != 0) {
-               ipv4_hdr = (struct ipv4_hdr *)l3_hdr;
-               tcp_hdr = (struct tcp_hdr *)((char *)l3_hdr + m->l3_len);
-               m->ol_flags |= PKT_TX_IP_CKSUM;
-               ipv4_hdr->hdr_checksum = 0;
-               tcp_hdr->cksum = get_psd_sum(l3_hdr, m->ol_flags);
-               return;
-       }
-
-       if (m->ol_flags & PKT_TX_L4_MASK) {
-               switch (m->ol_flags & PKT_TX_L4_MASK) {
-               case PKT_TX_TCP_CKSUM:
-                       tcp_hdr = (struct tcp_hdr *)
-                                       ((char *)l3_hdr + m->l3_len);
-                       tcp_hdr->cksum = get_psd_sum(l3_hdr, m->ol_flags);
-                       break;
-               case PKT_TX_UDP_CKSUM:
-                       udp_hdr = (struct udp_hdr *)
-                                       ((char *)l3_hdr + m->l3_len);
-                       udp_hdr->dgram_cksum = get_psd_sum(l3_hdr, m->ol_flags);
-                       break;
-               case PKT_TX_SCTP_CKSUM:
-                       sctp_hdr = (struct sctp_hdr *)
-                                       ((char *)l3_hdr + m->l3_len);
-                       sctp_hdr->cksum = 0;
-                       break;
-               default:
-                       break;
-               }
-       }
+       ipv4_hdr = (struct ipv4_hdr *)l3_hdr;
+       tcp_hdr = (struct tcp_hdr *)((char *)l3_hdr + m->l3_len);
+       m->ol_flags |= PKT_TX_IP_CKSUM;
+       ipv4_hdr->hdr_checksum = 0;
+       tcp_hdr->cksum = get_psd_sum(l3_hdr, m->ol_flags);
 }

 /*
@@ -1265,7 +1236,7 @@ virtio_tx_route(struct vhost_dev *vdev, struct rte_mbuf 
*m, uint16_t vlan_tag)
                m->vlan_tci = vlan_tag;
        }

-       if ((m->ol_flags & PKT_TX_L4_MASK) || (m->ol_flags & PKT_TX_TCP_SEG))
+       if (m->ol_flags & PKT_TX_TCP_SEG)
                virtio_tx_offload(m);

        tx_q->m_table[len] = m;
-- 
1.9.0