From 6828b92bd21acd65113dfe0541f19f5df0d9668f Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sun, 28 Jun 2009 18:06:41 +0000 Subject: [PATCH] tcp: Do not tack on TSO data to non-TSO packet If a socket starts out on a non-TSO route, and then switches to a TSO route, then we will tack on data to the tail of the tx queue even if it started out life as non-TSO. This is suboptimal because all of it will then be copied and checksummed unnecessarily. This patch fixes this by ensuring that skb->ip_summed is set to CHECKSUM_PARTIAL before appending extra data beyond the MSS. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- net/ipv4/tcp.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 17b89c5..7870a53 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -903,13 +903,17 @@ int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, iov++; while (seglen > 0) { - int copy; + int copy = 0; + int max = size_goal; skb = tcp_write_queue_tail(sk); + if (tcp_send_head(sk)) { + if (skb->ip_summed == CHECKSUM_NONE) + max = mss_now; + copy = max - skb->len; + } - if (!tcp_send_head(sk) || - (copy = size_goal - skb->len) <= 0) { - + if (copy <= 0) { new_segment: /* Allocate new segment. If the interface is SG, * allocate skb fitting to single page. @@ -930,6 +934,7 @@ new_segment: skb_entail(sk, skb); copy = size_goal; + max = size_goal; } /* Try to append data to the end of skb. */ @@ -1028,7 +1033,7 @@ new_segment: if ((seglen -= copy) == 0 && iovlen == 0) goto out; - if (skb->len < size_goal || (flags & MSG_OOB)) + if (skb->len < max || (flags & MSG_OOB)) continue; if (forced_push(tp)) { -- 2.7.4