diff options
| author | Eric Dumazet <edumazet@google.com> | 2019-12-12 21:55:30 +0100 |
|---|---|---|
| committer | Jakub Kicinski <jakub.kicinski@netronome.com> | 2019-12-14 06:58:40 +0100 |
| commit | ee2aabd3fc2eef4c1a0ebdadccc76fbff74b94fc (patch) | |
| tree | ff49c797d50165533687b248d7531010a9b24339 /net/ipv4/tcp_output.c | |
| parent | tcp: do not send empty skb from tcp_write_xmit() (diff) | |
| download | linux-ee2aabd3fc2eef4c1a0ebdadccc76fbff74b94fc.tar.xz linux-ee2aabd3fc2eef4c1a0ebdadccc76fbff74b94fc.zip | |
tcp: refine tcp_write_queue_empty() implementation
Due to how tcp_sendmsg() is implemented, we can have an empty
skb at the tail of the write queue.
Most [1] tcp_write_queue_empty() callers want to know if there is
anything to send (payload and/or FIN)
Instead of checking if the sk_write_queue is empty, we need
to test if tp->write_seq == tp->snd_nxt
[1] tcp_send_fin() was the only caller that expected to
see if an skb was in the write queue, I have changed the code
to reuse the tcp_write_queue_tail() result.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Diffstat (limited to 'net/ipv4/tcp_output.c')
| -rw-r--r-- | net/ipv4/tcp_output.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 57f434a8e41f..36902d08473e 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3129,7 +3129,7 @@ void sk_forced_mem_schedule(struct sock *sk, int size) */ void tcp_send_fin(struct sock *sk) { - struct sk_buff *skb, *tskb = tcp_write_queue_tail(sk); + struct sk_buff *skb, *tskb, *tail = tcp_write_queue_tail(sk); struct tcp_sock *tp = tcp_sk(sk); /* Optimization, tack on the FIN if we have one skb in write queue and @@ -3137,6 +3137,7 @@ void tcp_send_fin(struct sock *sk) * Note: in the latter case, FIN packet will be sent after a timeout, * as TCP stack thinks it has already been transmitted. */ + tskb = tail; if (!tskb && tcp_under_memory_pressure(sk)) tskb = skb_rb_last(&sk->tcp_rtx_queue); @@ -3144,7 +3145,7 @@ void tcp_send_fin(struct sock *sk) TCP_SKB_CB(tskb)->tcp_flags |= TCPHDR_FIN; TCP_SKB_CB(tskb)->end_seq++; tp->write_seq++; - if (tcp_write_queue_empty(sk)) { + if (!tail) { /* This means tskb was already sent. * Pretend we included the FIN on previous transmit. * We need to set tp->snd_nxt to the value it would have |