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 <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
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 @@
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 @@
skb_entail(sk, skb);
copy = size_goal;
+ max = size_goal;
}
/* Try to append data to the end of skb. */
@@ -1028,7 +1033,7 @@
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)) {