From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: [PATCH v2 net-next 2/7] tcp: do not block bh during prequeue processing Date: Thu, 28 Apr 2016 20:10:44 -0700 Message-ID: <1461899449-8096-3-git-send-email-edumazet@google.com> References: <1461899449-8096-1-git-send-email-edumazet@google.com> Cc: netdev , Eric Dumazet , Soheil Hassas Yeganeh , Alexei Starovoitov , Marcelo Ricardo Leitner , Eric Dumazet To: "David S . Miller" Return-path: Received: from mail-pa0-f51.google.com ([209.85.220.51]:34066 "EHLO mail-pa0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752788AbcD2DK7 (ORCPT ); Thu, 28 Apr 2016 23:10:59 -0400 Received: by mail-pa0-f51.google.com with SMTP id r5so40568500pag.1 for ; Thu, 28 Apr 2016 20:10:59 -0700 (PDT) In-Reply-To: <1461899449-8096-1-git-send-email-edumazet@google.com> Sender: netdev-owner@vger.kernel.org List-ID: AFAIK, nothing in current TCP stack absolutely wants BH being disabled once socket is owned by a thread running in process context. As mentioned in my prior patch ("tcp: give prequeue mode some care"), processing a batch of packets might take time, better not block BH at all. Signed-off-by: Eric Dumazet --- net/ipv4/tcp.c | 4 ---- net/ipv4/tcp_input.c | 30 ++---------------------------- 2 files changed, 2 insertions(+), 32 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index b24c6ed4a04f..4787f86ae64c 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1449,12 +1449,8 @@ static void tcp_prequeue_process(struct sock *sk) NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPPREQUEUED); - /* RX process wants to run with disabled BHs, though it is not - * necessary */ - local_bh_disable(); while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) sk_backlog_rcv(sk, skb); - local_bh_enable(); /* Clear memory counter. */ tp->ucopy.memory = 0; diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index ac85fb42a5a2..6171f92be090 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4611,14 +4611,12 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb) __set_current_state(TASK_RUNNING); - local_bh_enable(); if (!skb_copy_datagram_msg(skb, 0, tp->ucopy.msg, chunk)) { tp->ucopy.len -= chunk; tp->copied_seq += chunk; eaten = (chunk == skb->len); tcp_rcv_space_adjust(sk); } - local_bh_disable(); } if (eaten <= 0) { @@ -5134,7 +5132,6 @@ static int tcp_copy_to_iovec(struct sock *sk, struct sk_buff *skb, int hlen) int chunk = skb->len - hlen; int err; - local_bh_enable(); if (skb_csum_unnecessary(skb)) err = skb_copy_datagram_msg(skb, hlen, tp->ucopy.msg, chunk); else @@ -5146,32 +5143,9 @@ static int tcp_copy_to_iovec(struct sock *sk, struct sk_buff *skb, int hlen) tcp_rcv_space_adjust(sk); } - local_bh_disable(); return err; } -static __sum16 __tcp_checksum_complete_user(struct sock *sk, - struct sk_buff *skb) -{ - __sum16 result; - - if (sock_owned_by_user(sk)) { - local_bh_enable(); - result = __tcp_checksum_complete(skb); - local_bh_disable(); - } else { - result = __tcp_checksum_complete(skb); - } - return result; -} - -static inline bool tcp_checksum_complete_user(struct sock *sk, - struct sk_buff *skb) -{ - return !skb_csum_unnecessary(skb) && - __tcp_checksum_complete_user(sk, skb); -} - /* Does PAWS and seqno based validation of an incoming segment, flags will * play significant role here. */ @@ -5386,7 +5360,7 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb, } } if (!eaten) { - if (tcp_checksum_complete_user(sk, skb)) + if (tcp_checksum_complete(skb)) goto csum_error; if ((int)skb->truesize > sk->sk_forward_alloc) @@ -5430,7 +5404,7 @@ no_ack: } slow_path: - if (len < (th->doff << 2) || tcp_checksum_complete_user(sk, skb)) + if (len < (th->doff << 2) || tcp_checksum_complete(skb)) goto csum_error; if (!th->ack && !th->rst && !th->syn) -- 2.8.0.rc3.226.g39d4020