From 05dc72aba364d374a27de567fac58c199ff5ee97 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 12 Feb 2021 15:22:14 -0800 Subject: [PATCH] tcp: factorize logic into tcp_epollin_ready() Both tcp_data_ready() and tcp_stream_is_readable() share the same logic. Add tcp_epollin_ready() helper to avoid duplication. Signed-off-by: Eric Dumazet Cc: Arjun Roy Cc: Wei Wang Signed-off-by: David S. Miller --- include/net/tcp.h | 12 ++++++++++++ net/ipv4/tcp.c | 16 ++++------------ net/ipv4/tcp_input.c | 11 ++--------- 3 files changed, 18 insertions(+), 21 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 244208f6f6c2..484eb2362645 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1442,6 +1442,18 @@ static inline bool tcp_rmem_pressure(const struct sock *sk) return atomic_read(&sk->sk_rmem_alloc) > threshold; } +static inline bool tcp_epollin_ready(const struct sock *sk, int target) +{ + const struct tcp_sock *tp = tcp_sk(sk); + int avail = READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->copied_seq); + + if (avail <= 0) + return false; + + return (avail >= target) || tcp_rmem_pressure(sk) || + (tcp_receive_window(tp) <= inet_csk(sk)->icsk_ack.rcv_mss); +} + extern void tcp_openreq_init_rwin(struct request_sock *req, const struct sock *sk_listener, const struct dst_entry *dst); diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 9896ca10bb34..7a6b58ae408d 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -481,19 +481,11 @@ static void tcp_tx_timestamp(struct sock *sk, u16 tsflags) } } -static inline bool tcp_stream_is_readable(const struct tcp_sock *tp, - int target, struct sock *sk) +static bool tcp_stream_is_readable(struct sock *sk, int target) { - int avail = READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->copied_seq); + if (tcp_epollin_ready(sk, target)) + return true; - if (avail > 0) { - if (avail >= target) - return true; - if (tcp_rmem_pressure(sk)) - return true; - if (tcp_receive_window(tp) <= inet_csk(sk)->icsk_ack.rcv_mss) - return true; - } if (sk->sk_prot->stream_memory_read) return sk->sk_prot->stream_memory_read(sk); return false; @@ -568,7 +560,7 @@ __poll_t tcp_poll(struct file *file, struct socket *sock, poll_table *wait) tp->urg_data) target++; - if (tcp_stream_is_readable(tp, target, sk)) + if (tcp_stream_is_readable(sk, target)) mask |= EPOLLIN | EPOLLRDNORM; if (!(sk->sk_shutdown & SEND_SHUTDOWN)) { diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index a8f8f9815953..e32a7056cb76 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4924,15 +4924,8 @@ err: void tcp_data_ready(struct sock *sk) { - const struct tcp_sock *tp = tcp_sk(sk); - int avail = tp->rcv_nxt - tp->copied_seq; - - if (avail < sk->sk_rcvlowat && !tcp_rmem_pressure(sk) && - !sock_flag(sk, SOCK_DONE) && - tcp_receive_window(tp) > inet_csk(sk)->icsk_ack.rcv_mss) - return; - - sk->sk_data_ready(sk); + if (tcp_epollin_ready(sk, sk->sk_rcvlowat)) + sk->sk_data_ready(sk); } static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)