Commit e063af97 authored by Neil Brown's avatar Neil Brown Committed by Linus Torvalds

[PATCH] Avoid copying unfragmented udp NFS requests.

If an NFS request arrives in a linear skb,
we don't need to copy it, particularly if the
network card has already done the DUB checksum.

This patch only copies a request if it is
already non-linear.
parent f4c4c4ae
......@@ -564,16 +564,39 @@ svc_udp_recvfrom(struct svc_rqst *rqstp)
set_bit(SK_DATA, &svsk->sk_flags); /* there may be more data... */
len = skb->len - sizeof(struct udphdr);
rqstp->rq_arg.len = len;
if (csum_partial_copy_to_xdr(&rqstp->rq_arg, skb)) {
/* checksum error */
skb_free_datagram(svsk->sk_sk, skb);
svc_sock_received(svsk);
return 0;
}
rqstp->rq_prot = IPPROTO_UDP;
/* Get sender address */
rqstp->rq_addr.sin_family = AF_INET;
rqstp->rq_addr.sin_port = skb->h.uh->source;
rqstp->rq_addr.sin_addr.s_addr = skb->nh.iph->saddr;
if (skb_is_nonlinear(skb)) {
/* we have to copy */
if (csum_partial_copy_to_xdr(&rqstp->rq_arg, skb)) {
/* checksum error */
skb_free_datagram(svsk->sk_sk, skb);
svc_sock_received(svsk);
return 0;
}
skb_free_datagram(svsk->sk_sk, skb);
} else {
/* we can use it in-place */
rqstp->rq_arg.head[0].iov_base = skb->data + sizeof(struct udphdr);
rqstp->rq_arg.head[0].iov_len = len;
if (skb->ip_summed != CHECKSUM_UNNECESSARY) {
if ((unsigned short)csum_fold(skb_checksum(skb, 0, skb->len, skb->csum))) {
skb_free_datagram(svsk->sk_sk, skb);
svc_sock_received(svsk);
return 0;
}
skb->ip_summed = CHECKSUM_UNNECESSARY;
}
rqstp->rq_skbuff = skb;
}
rqstp->rq_arg.len = len;
rqstp->rq_arg.page_base = 0;
if (len <= rqstp->rq_arg.head[0].iov_len) {
rqstp->rq_arg.head[0].iov_len = len;
......@@ -582,14 +605,6 @@ svc_udp_recvfrom(struct svc_rqst *rqstp)
rqstp->rq_arg.page_len = len - rqstp->rq_arg.head[0].iov_len;
rqstp->rq_argused += (rqstp->rq_arg.page_len + PAGE_SIZE - 1)/ PAGE_SIZE;
}
rqstp->rq_prot = IPPROTO_UDP;
/* Get sender address */
rqstp->rq_addr.sin_family = AF_INET;
rqstp->rq_addr.sin_port = skb->h.uh->source;
rqstp->rq_addr.sin_addr.s_addr = skb->nh.iph->saddr;
skb_free_datagram(svsk->sk_sk, skb);
if (serv->sv_stats)
serv->sv_stats->netudpcnt++;
......
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