gro: Use gso_size to store MSS

In order to allow GRO packets without frag_list at all, we need to
store the MSS in the packet itself.  The obvious place is gso_size.
The only thing to watch out for is if the packet ends up not being
GRO then we need to clear gso_size before pushing the packet into
the stack.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 4 deletions

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index f28acf11fc67..4d655e945413 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2519,9 +2519,7 @@ found:
         flush |= memcmp(th + 1, th2 + 1, thlen - sizeof(*th));
 
         total = p->len;
-        mss = total;
-        if (skb_shinfo(p)->frag_list)
-                mss = skb_shinfo(p)->frag_list->len;
+        mss = skb_shinfo(p)->gso_size;
 
         flush |= skb->len > mss || skb->len <= 0;
         flush |= ntohl(th2->seq) + total != ntohl(th->seq);
@@ -2557,7 +2555,6 @@ int tcp_gro_complete(struct sk_buff *skb)
         skb->csum_offset = offsetof(struct tcphdr, check);
         skb->ip_summed = CHECKSUM_PARTIAL;
 
-        skb_shinfo(skb)->gso_size = skb_shinfo(skb)->frag_list->len;
         skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
 
         if (th->cwr)