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[146.241.113.89]) by smtp.gmail.com with ESMTPSA id g12-20020ac842cc000000b002f39b99f678sm9342697qtm.18.2022.05.10.04.05.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 May 2022 04:05:27 -0700 (PDT) Message-ID: Subject: Re: [PATCH net 2/2] net/smc: align the connect behaviour with TCP From: Paolo Abeni To: Guangguan Wang , kgraul@linux.ibm.com, davem@davemloft.net, kuba@kernel.org Cc: linux-s390@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Date: Tue, 10 May 2022 13:05:24 +0200 In-Reply-To: <20220509115837.94911-3-guangguan.wang@linux.alibaba.com> References: <20220509115837.94911-1-guangguan.wang@linux.alibaba.com> <20220509115837.94911-3-guangguan.wang@linux.alibaba.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.42.4 (3.42.4-2.fc35) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-s390@vger.kernel.org On Mon, 2022-05-09 at 19:58 +0800, Guangguan Wang wrote: > Connect with O_NONBLOCK will not be completed immediately > and returns -EINPROGRESS. It is possible to use selector/poll > for completion by selecting the socket for writing. After select > indicates writability, a second connect function call will return > 0 to indicate connected successfully as TCP does, but smc returns > -EISCONN. Use socket state for smc to indicate connect state, which > can help smc aligning the connect behaviour with TCP. > > Signed-off-by: Guangguan Wang > --- > net/smc/af_smc.c | 53 ++++++++++++++++++++++++++++++++++++++++++++---- > 1 file changed, 49 insertions(+), 4 deletions(-) > > diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c > index fce16b9d6e1a..45f9f7c6e776 100644 > --- a/net/smc/af_smc.c > +++ b/net/smc/af_smc.c > @@ -1544,9 +1544,32 @@ static int smc_connect(struct socket *sock, struct sockaddr *addr, > goto out_err; > > lock_sock(sk); > + switch (sock->state) { > + default: > + rc = -EINVAL; > + goto out; > + case SS_CONNECTED: > + rc = sk->sk_state == SMC_ACTIVE ? -EISCONN : -EINVAL; > + goto out; > + case SS_CONNECTING: > + if (sk->sk_state == SMC_ACTIVE) { > + sock->state = SS_CONNECTED; > + rc = 0; > + goto out; > + } > + break; > + case SS_UNCONNECTED: > + sock->state = SS_CONNECTING; > + break; > + } > + > switch (sk->sk_state) { > default: > goto out; > + case SMC_CLOSED: > + rc = sock_error(sk) ? : -ECONNABORTED; > + sock->state = SS_UNCONNECTED; > + goto out; > case SMC_ACTIVE: > rc = -EISCONN; > goto out; > @@ -1565,18 +1588,22 @@ static int smc_connect(struct socket *sock, struct sockaddr *addr, > goto out; > > sock_hold(&smc->sk); /* sock put in passive closing */ > - if (smc->use_fallback) > + if (smc->use_fallback) { > + sock->state = SS_CONNECTED; > goto out; > + } > if (flags & O_NONBLOCK) { > if (queue_work(smc_hs_wq, &smc->connect_work)) > smc->connect_nonblock = 1; > rc = -EINPROGRESS; > } else { > rc = __smc_connect(smc); > - if (rc < 0) > + if (rc < 0) { > goto out; > - else > + } else { > rc = 0; /* success cases including fallback */ > + sock->state = SS_CONNECTED; 'else' is not needed here, you can keep the above 2 statements dropping an indentation level. > + } > } > You can avoid a little code duplication adding here the following: connected: sock->state = SS_CONNECTED; and using the new label where appropriate. > out: > @@ -1693,6 +1720,7 @@ struct sock *smc_accept_dequeue(struct sock *parent, > } > if (new_sock) { > sock_graft(new_sk, new_sock); > + new_sock->state = SS_CONNECTED; > if (isk->use_fallback) { > smc_sk(new_sk)->clcsock->file = new_sock->file; > isk->clcsock->file->private_data = isk->clcsock; > @@ -2424,7 +2452,7 @@ static int smc_listen(struct socket *sock, int backlog) > > rc = -EINVAL; > if ((sk->sk_state != SMC_INIT && sk->sk_state != SMC_LISTEN) || > - smc->connect_nonblock) > + smc->connect_nonblock || sock->state != SS_UNCONNECTED) > goto out; > > rc = 0; > @@ -2716,6 +2744,17 @@ static int smc_shutdown(struct socket *sock, int how) > > lock_sock(sk); > > + if (sock->state == SS_CONNECTING) { > + if (sk->sk_state == SMC_ACTIVE) > + sock->state = SS_CONNECTED; > + else if (sk->sk_state == SMC_PEERCLOSEWAIT1 || > + sk->sk_state == SMC_PEERCLOSEWAIT2 || > + sk->sk_state == SMC_APPCLOSEWAIT1 || > + sk->sk_state == SMC_APPCLOSEWAIT2 || > + sk->sk_state == SMC_APPFINCLOSEWAIT) > + sock->state = SS_DISCONNECTING; > + } > + > rc = -ENOTCONN; > if ((sk->sk_state != SMC_ACTIVE) && > (sk->sk_state != SMC_PEERCLOSEWAIT1) && > @@ -2729,6 +2768,7 @@ static int smc_shutdown(struct socket *sock, int how) > sk->sk_shutdown = smc->clcsock->sk->sk_shutdown; > if (sk->sk_shutdown == SHUTDOWN_MASK) { > sk->sk_state = SMC_CLOSED; > + sk->sk_socket->state = SS_UNCONNECTED; > sock_put(sk); > } > goto out; > @@ -2754,6 +2794,10 @@ static int smc_shutdown(struct socket *sock, int how) > /* map sock_shutdown_cmd constants to sk_shutdown value range */ > sk->sk_shutdown |= how + 1; > > + if (sk->sk_state == SMC_CLOSED) > + sock->state = SS_UNCONNECTED; > + else > + sock->state = SS_DISCONNECTING; > out: > release_sock(sk); > return rc ? rc : rc1; > @@ -3139,6 +3183,7 @@ static int __smc_create(struct net *net, struct socket *sock, int protocol, > > rc = -ENOBUFS; > sock->ops = &smc_sock_ops; > + sock->state = SS_UNCONNECTED; > sk = smc_sock_alloc(net, sock, protocol); > if (!sk) > goto out;