From 33f5f57eeb0c6386fdd85f9c690dc8d700ba7928 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ilpo=20J=C3=A4rvinen?= Date: Tue, 7 Oct 2008 14:43:06 -0700 Subject: [PATCH] tcp: kill pointless urg_mode MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 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 --- include/linux/tcp.h | 9 ++++----- net/ipv4/tcp.c | 4 +--- net/ipv4/tcp_input.c | 11 ++++++----- net/ipv4/tcp_minisocks.c | 1 + net/ipv4/tcp_output.c | 18 ++++++++++++------ 5 files changed, 24 insertions(+), 19 deletions(-) diff --git a/include/linux/tcp.h b/include/linux/tcp.h index 767290628292..fe77e1499ab7 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -312,8 +312,11 @@ struct tcp_sock { u32 retrans_out; /* Retransmitted packets out */ u16 urg_data; /* Saved octet of OOB data and control flags */ - u8 urg_mode; /* In urgent mode */ u8 ecn_flags; /* ECN status bits. */ + u8 reordering; /* Packet reordering metric. */ + u32 snd_up; /* Urgent pointer */ + + u8 keepalive_probes; /* num of allowed keep alive probes */ /* * Options received (usually on last packet, some only on SYN packets). */ @@ -361,8 +364,6 @@ struct tcp_sock { u32 lost_retrans_low; /* Sent seq after any rxmit (lowest) */ - u8 reordering; /* Packet reordering metric. */ - u8 keepalive_probes; /* num of allowed keep alive probes */ u32 prior_ssthresh; /* ssthresh saved at recovery start */ u32 high_seq; /* snd_nxt at onset of congestion */ @@ -374,8 +375,6 @@ struct tcp_sock { u32 total_retrans; /* Total retransmits for entire connection */ u32 urg_seq; /* Seq of received urgent pointer */ - u32 snd_up; /* Urgent pointer */ - unsigned int keepalive_time; /* time before keep alive takes place */ unsigned int keepalive_intvl; /* time interval between keep alive probes */ diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 7d3fe571d15f..eccb7165a80c 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -497,10 +497,8 @@ static inline void skb_entail(struct sock *sk, struct sk_buff *skb) static inline void tcp_mark_urg(struct tcp_sock *tp, int flags, struct sk_buff *skb) { - if (flags & MSG_OOB) { - tp->urg_mode = 1; + if (flags & MSG_OOB) tp->snd_up = tp->write_seq; - } } static inline void tcp_push(struct sock *sk, int flags, int mss_now, diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 3b76bce769dd..c19f429dc443 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2836,7 +2836,8 @@ static u32 tcp_tso_acked(struct sock *sk, struct sk_buff *skb) * is before the ack sequence we can discard it as it's confirmed to have * arrived at the other end. */ -static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets) +static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets, + u32 prior_snd_una) { struct tcp_sock *tp = tcp_sk(sk); const struct inet_connection_sock *icsk = inet_csk(sk); @@ -2903,9 +2904,6 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets) if (sacked & TCPCB_LOST) tp->lost_out -= acked_pcount; - if (unlikely(tp->urg_mode && !before(end_seq, tp->snd_up))) - tp->urg_mode = 0; - tp->packets_out -= acked_pcount; pkts_acked += acked_pcount; @@ -2935,6 +2933,9 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets) tp->lost_skb_hint = NULL; } + if (likely(between(tp->snd_up, prior_snd_una, tp->snd_una))) + tp->snd_up = tp->snd_una; + if (skb && (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)) flag |= FLAG_SACK_RENEGING; @@ -3311,7 +3312,7 @@ static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag) goto no_queue; /* See if we can take anything off of the retransmit queue. */ - flag |= tcp_clean_rtx_queue(sk, prior_fackets); + flag |= tcp_clean_rtx_queue(sk, prior_fackets, prior_snd_una); if (tp->frto_counter) frto_cwnd = tcp_process_frto(sk, flag); diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index f976fc57892c..779f2e9d0689 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -395,6 +395,7 @@ struct sock *tcp_create_openreq_child(struct sock *sk, struct request_sock *req, newtp->pred_flags = 0; newtp->rcv_wup = newtp->copied_seq = newtp->rcv_nxt = treq->rcv_isn + 1; newtp->snd_sml = newtp->snd_una = newtp->snd_nxt = treq->snt_isn + 1; + newtp->snd_up = treq->snt_isn + 1; tcp_prequeue_init(newtp); 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); } -- 2.20.1