vmxnet3: Provide required number of bytes in first SG buffer

This is a performance enhancement fix. vmxnet3 device performs better when
provided with at least 54 bytes (ethernet 14 + IP 20+ TCP 20) in the first SG
buffer. For UDP packets driver provides lesser than that in first sg. This
change fixes the same. Also avoid the redundant pskb_may_pull() call.

Signed-off-by: Shreyas N Bhatewara <sbhatewara@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
index f47db1c..a1632a9 100644 (file)
--- a/drivers/net/vmxnet3/vmxnet3_drv.c
+++ b/drivers/net/vmxnet3/vmxnet3_drv.c
@@ -807,30 +807,25 @@ vmxnet3_parse_and_copy_hdr(struct sk_buff *skb, struct vmxnet3_tx_queue *tq,
                                   skb_transport_header(skb))->doff * 4;
                ctx->copy_size = ctx->eth_ip_hdr_size + ctx->l4_hdr_size;
        } else {
-               unsigned int pull_size;
-
                if (skb->ip_summed == CHECKSUM_PARTIAL) {
                        ctx->eth_ip_hdr_size = skb_checksum_start_offset(skb);
 
                        if (ctx->ipv4) {
                                struct iphdr *iph = (struct iphdr *)
                                                    skb_network_header(skb);
-                               if (iph->protocol == IPPROTO_TCP) {
-                                       pull_size = ctx->eth_ip_hdr_size +
-                                                   sizeof(struct tcphdr);
-
-                                       if (unlikely(!pskb_may_pull(skb,
-                                                               pull_size))) {
-                                               goto err;
-                                       }
+                               if (iph->protocol == IPPROTO_TCP)
                                        ctx->l4_hdr_size = ((struct tcphdr *)
                                           skb_transport_header(skb))->doff * 4;
-                               } else if (iph->protocol == IPPROTO_UDP) {
+                               else if (iph->protocol == IPPROTO_UDP)
+                                       /*
+                                        * Use tcp header size so that bytes to
+                                        * be copied are more than required by
+                                        * the device.
+                                        */
                                        ctx->l4_hdr_size =
-                                                       sizeof(struct udphdr);
-                               } else {
+                                                       sizeof(struct tcphdr);
+                               else
                                        ctx->l4_hdr_size = 0;
-                               }
                        } else {
                                /* for simplicity, don't copy L4 headers */
                                ctx->l4_hdr_size = 0;