From 33f5f57eeb0c6386fdd85f9c690dc8d700ba7928 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Tue, 7 Oct 2008 14:43:06 -0700 Subject: tcp: kill pointless urg_mode MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit It all started from me noticing that this urgent check in tcp_clean_rtx_queue is unnecessarily inside the loop. Then I took a longer look to it and found out that the users of urg_mode can trivially do without, well almost, there was one gotcha. Bonus: those funny people who use urg with >= 2^31 write_seq - snd_una could now rejoice too (that's the only purpose for the between being there, otherwise a simple compare would have done the thing). Not that I assume that the rest of the tcp code happily lives with such mind-boggling numbers :-). Alas, it turned out to be impossible to set wmem to such numbers anyway, yes I really tried a big sendfile after setting some wmem but nothing happened :-). ...Tcp_wmem is int and so is sk_sndbuf... So I hacked a bit variable to long and found out that it seems to work... :-) Signed-off-by: Ilpo Järvinen Signed-off-by: David S. Miller --- net/ipv4/tcp_output.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) (limited to 'net/ipv4/tcp_output.c') diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 493553c71d32..990a58493235 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -345,6 +345,11 @@ static void tcp_init_nondata_skb(struct sk_buff *skb, u32 seq, u8 flags) TCP_SKB_CB(skb)->end_seq = seq; } +static inline int tcp_urg_mode(const struct tcp_sock *tp) +{ + return tp->snd_una != tp->snd_up; +} + #define OPTION_SACK_ADVERTISE (1 << 0) #define OPTION_TS (1 << 1) #define OPTION_MD5 (1 << 2) @@ -646,7 +651,8 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it, th->check = 0; th->urg_ptr = 0; - if (unlikely(tp->urg_mode && + /* The urg_mode check is necessary during a below snd_una win probe */ + if (unlikely(tcp_urg_mode(tp) && between(tp->snd_up, tcb->seq + 1, tcb->seq + 0xFFFF))) { th->urg_ptr = htons(tp->snd_up - tcb->seq); th->urg = 1; @@ -1012,7 +1018,7 @@ unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu) /* Compute the current effective MSS, taking SACKs and IP options, * and even PMTU discovery events into account. * - * LARGESEND note: !urg_mode is overkill, only frames up to snd_up + * LARGESEND note: !tcp_urg_mode is overkill, only frames up to snd_up * cannot be large. However, taking into account rare use of URG, this * is not a big flaw. */ @@ -1029,7 +1035,7 @@ unsigned int tcp_current_mss(struct sock *sk, int large_allowed) mss_now = tp->mss_cache; - if (large_allowed && sk_can_gso(sk) && !tp->urg_mode) + if (large_allowed && sk_can_gso(sk) && !tcp_urg_mode(tp)) doing_tso = 1; if (dst) { @@ -1193,7 +1199,7 @@ static inline int tcp_nagle_test(struct tcp_sock *tp, struct sk_buff *skb, /* Don't use the nagle rule for urgent data (or for the final FIN). * Nagle can be ignored during F-RTO too (see RFC4138). */ - if (tp->urg_mode || (tp->frto_counter == 2) || + if (tcp_urg_mode(tp) || (tp->frto_counter == 2) || (TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN)) return 1; @@ -2358,6 +2364,7 @@ static void tcp_connect_init(struct sock *sk) tcp_init_wl(tp, tp->write_seq, 0); tp->snd_una = tp->write_seq; tp->snd_sml = tp->write_seq; + tp->snd_up = tp->write_seq; tp->rcv_nxt = 0; tp->rcv_wup = 0; tp->copied_seq = 0; @@ -2567,8 +2574,7 @@ int tcp_write_wakeup(struct sock *sk) tcp_event_new_data_sent(sk, skb); return err; } else { - if (tp->urg_mode && - between(tp->snd_up, tp->snd_una + 1, tp->snd_una + 0xFFFF)) + if (between(tp->snd_up, tp->snd_una + 1, tp->snd_una + 0xFFFF)) tcp_xmit_probe_skb(sk, 1); return tcp_xmit_probe_skb(sk, 0); } -- cgit v1.2.2