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tcp: factorize logic into tcp_epollin_ready()

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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 <edumazet@google.com>
Cc: Arjun Roy <arjunroy@google.com>
Cc: Wei Wang <weiwan@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2021-02-12 15:22:14 -08:00 committed by David S. Miller
parent f969dc5a88
commit 05dc72aba3
3 changed files with 18 additions and 21 deletions
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12
include/net/tcp.h
View File

@ -1442,6 +1442,18 @@ static inline bool tcp_rmem_pressure(const struct sock *sk)
return atomic_read(&sk->sk_rmem_alloc) > threshold; 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, extern void tcp_openreq_init_rwin(struct request_sock *req,
const struct sock *sk_listener, const struct sock *sk_listener,
const struct dst_entry *dst); const struct dst_entry *dst);

16
net/ipv4/tcp.c
View File

@ -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, static bool tcp_stream_is_readable(struct sock *sk, int target)
int target, struct sock *sk)
{ {
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) if (sk->sk_prot->stream_memory_read)
return sk->sk_prot->stream_memory_read(sk); return sk->sk_prot->stream_memory_read(sk);
return false; return false;
@ -568,7 +560,7 @@ __poll_t tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
tp->urg_data) tp->urg_data)
target++; target++;
if (tcp_stream_is_readable(tp, target, sk)) if (tcp_stream_is_readable(sk, target))
mask |= EPOLLIN | EPOLLRDNORM; mask |= EPOLLIN | EPOLLRDNORM;
if (!(sk->sk_shutdown & SEND_SHUTDOWN)) { if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {

11
net/ipv4/tcp_input.c
View File

@ -4924,15 +4924,8 @@ err:
void tcp_data_ready(struct sock *sk) void tcp_data_ready(struct sock *sk)
{ {
const struct tcp_sock *tp = tcp_sk(sk); if (tcp_epollin_ready(sk, sk->sk_rcvlowat))
int avail = tp->rcv_nxt - tp->copied_seq; sk->sk_data_ready(sk);
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);
} }
static void tcp_data_queue(struct sock *sk, struct sk_buff *skb) static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)