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Commit 6828b92b authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller
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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: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8e5b9dda

net/ipv4/tcp.c

+10 −5
Original line number Diff line number Diff line
@@ -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 @@ int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, 


				skb_entail(sk, skb);

				copy = size_goal;

				max = size_goal;

			}



			/* Try to append data to the end of skb. */
@@ -1028,7 +1033,7 @@ int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, 
			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)) {