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[79.34.249.199]) by smtp.gmail.com with ESMTPSA id x25sm1728972wmk.20.2021.01.18.06.52.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Jan 2021 06:52:01 -0800 (PST) Date: Mon, 18 Jan 2021 15:51:58 +0100 From: Stefano Garzarella To: Arseny Krasnov Cc: Stefan Hajnoczi , "Michael S. Tsirkin" , Jason Wang , "David S. Miller" , Jakub Kicinski , Colin Ian King , Andra Paraschiv , Jeff Vander Stoep , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stsp2@yandex.ru, oxffffaa@gmail.com Subject: Re: [RFC PATCH v2 01/13] af_vsock: implement 'vsock_wait_data()'. Message-ID: <20210118145158.ufakay5mbezjex4v@steredhat> References: <20210115053553.1454517-1-arseny.krasnov@kaspersky.com> <20210115054028.1455574-1-arseny.krasnov@kaspersky.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20210115054028.1455574-1-arseny.krasnov@kaspersky.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 15, 2021 at 08:40:25AM +0300, Arseny Krasnov wrote: >This adds 'vsock_wait_data()' function which is called from user's read >syscall and waits until new socket data is arrived. It was based on code >from stream dequeue logic and moved to separate function because it will >be called both from SOCK_STREAM and SOCK_SEQPACKET receive loops. > >Signed-off-by: Arseny Krasnov >--- > net/vmw_vsock/af_vsock.c | 47 ++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 47 insertions(+) > >diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c >index b12d3a322242..af716f5a93a4 100644 >--- a/net/vmw_vsock/af_vsock.c >+++ b/net/vmw_vsock/af_vsock.c >@@ -1822,6 +1822,53 @@ static int vsock_stream_sendmsg(struct socket *sock, struct msghdr *msg, > return err; > } > >+static int vsock_wait_data(struct sock *sk, struct wait_queue_entry *wait, >+ long timeout, >+ struct vsock_transport_recv_notify_data *recv_data, >+ size_t target) >+{ >+ int err = 0; >+ struct vsock_sock *vsk; >+ const struct vsock_transport *transport; Please be sure that here and in all of the next patches, you follow the "Reverse Christmas tree" rule followed in net/ for the local variable declarations (order variable declaration lines longest to shortest). >+ >+ vsk = vsock_sk(sk); >+ transport = vsk->transport; >+ >+ if (sk->sk_err != 0 || >+ (sk->sk_shutdown & RCV_SHUTDOWN) || >+ (vsk->peer_shutdown & SEND_SHUTDOWN)) { >+ finish_wait(sk_sleep(sk), wait); >+ return -1; >+ } >+ /* Don't wait for non-blocking sockets. */ >+ if (timeout == 0) { >+ err = -EAGAIN; >+ finish_wait(sk_sleep(sk), wait); >+ return err; >+ } >+ >+ if (recv_data) { >+ err = transport->notify_recv_pre_block(vsk, target, recv_data); >+ if (err < 0) { >+ finish_wait(sk_sleep(sk), wait); >+ return err; >+ } >+ } >+ >+ release_sock(sk); >+ timeout = schedule_timeout(timeout); >+ lock_sock(sk); >+ >+ if (signal_pending(current)) { >+ err = sock_intr_errno(timeout); >+ finish_wait(sk_sleep(sk), wait); >+ } else if (timeout == 0) { >+ err = -EAGAIN; >+ finish_wait(sk_sleep(sk), wait); >+ } >+ Since we are calling finish_wait() before return in all path, why not doing somethig like this: out: finish_wait(sk_sleep(sk), wait); >+ return err; >+} Then in the error paths you can do: err = XXX; goto out; Thanks, Stefano > > static int > vsock_stream_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, >-- >2.25.1 >