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| author | Eric Dumazet <edumazet@google.com> | 2012-07-23 09:48:52 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-07-23 09:58:46 +0200 |
| commit | 563d34d05786263893ba4a1042eb9b9374127cf5 (patch) | |
| tree | e9ce502c1f32bea966c81d5597d0a29eb4b9d244 /net/ipv4/tcp_output.c | |
| parent | bnx2x: Add new 57840 device IDs (diff) | |
| download | linux-563d34d05786263893ba4a1042eb9b9374127cf5.tar.xz linux-563d34d05786263893ba4a1042eb9b9374127cf5.zip | |
tcp: dont drop MTU reduction indications
ICMP messages generated in output path if frame length is bigger than
mtu are actually lost because socket is owned by user (doing the xmit)
One example is the ipgre_tunnel_xmit() calling
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
We had a similar case fixed in commit a34a101e1e6 (ipv6: disable GSO on
sockets hitting dst_allfrag).
Problem of such fix is that it relied on retransmit timers, so short tcp
sessions paid a too big latency increase price.
This patch uses the tcp_release_cb() infrastructure so that MTU
reduction messages (ICMP messages) are not lost, and no extra delay
is added in TCP transmits.
Reported-by: Maciej Żenczykowski <maze@google.com>
Diagnosed-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Nandita Dukkipati <nanditad@google.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Tore Anderson <tore@fud.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_output.c')
| -rw-r--r-- | net/ipv4/tcp_output.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 950aebfd9967..33cd065cfbd8 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -885,7 +885,8 @@ static void tcp_tasklet_func(unsigned long data) #define TCP_DEFERRED_ALL ((1UL << TCP_TSQ_DEFERRED) | \ (1UL << TCP_WRITE_TIMER_DEFERRED) | \ - (1UL << TCP_DELACK_TIMER_DEFERRED)) + (1UL << TCP_DELACK_TIMER_DEFERRED) | \ + (1UL << TCP_MTU_REDUCED_DEFERRED)) /** * tcp_release_cb - tcp release_sock() callback * @sk: socket @@ -914,6 +915,9 @@ void tcp_release_cb(struct sock *sk) if (flags & (1UL << TCP_DELACK_TIMER_DEFERRED)) tcp_delack_timer_handler(sk); + + if (flags & (1UL << TCP_MTU_REDUCED_DEFERRED)) + sk->sk_prot->mtu_reduced(sk); } EXPORT_SYMBOL(tcp_release_cb); |