Jorgen Hansen
2021-Feb-11 15:11 UTC
[RFC PATCH v4 02/17] af_vsock: separate wait data loop
> On 7 Feb 2021, at 16:14, Arseny Krasnov <arseny.krasnov at kaspersky.com> wrote: > > This moves wait loop for data to dedicated function, because later > it will be used by SEQPACKET data receive loop. > > Signed-off-by: Arseny Krasnov <arseny.krasnov at kaspersky.com> > --- > net/vmw_vsock/af_vsock.c | 158 +++++++++++++++++++++------------------ > 1 file changed, 86 insertions(+), 72 deletions(-) > > diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c > index f4fabec50650..38927695786f 100644 > --- a/net/vmw_vsock/af_vsock.c > +++ b/net/vmw_vsock/af_vsock.c > @@ -1833,6 +1833,71 @@ static int vsock_connectible_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) > +{ > + const struct vsock_transport *transport; > + struct vsock_sock *vsk; > + s64 data; > + int err; > + > + vsk = vsock_sk(sk); > + err = 0; > + transport = vsk->transport; > + prepare_to_wait(sk_sleep(sk), wait, TASK_INTERRUPTIBLE); > + > + while ((data = vsock_stream_has_data(vsk)) == 0) { > + if (sk->sk_err != 0 || > + (sk->sk_shutdown & RCV_SHUTDOWN) || > + (vsk->peer_shutdown & SEND_SHUTDOWN)) { > + goto out; > + } > + > + /* Don't wait for non-blocking sockets. */ > + if (timeout == 0) { > + err = -EAGAIN; > + goto out; > + } > + > + if (recv_data) { > + err = transport->notify_recv_pre_block(vsk, target, recv_data); > + if (err < 0) > + goto out; > + } > + > + release_sock(sk); > + timeout = schedule_timeout(timeout); > + lock_sock(sk); > + > + if (signal_pending(current)) { > + err = sock_intr_errno(timeout); > + goto out; > + } else if (timeout == 0) { > + err = -EAGAIN; > + goto out; > + } > + } > + > + finish_wait(sk_sleep(sk), wait); > + > + /* Invalid queue pair content. XXX This should > + * be changed to a connection reset in a later > + * change. > + */Since you are here, could you update this comment to something like: /* Internal transport error when checking for available * data. XXX This should be changed to a connection * reset in a later change. */> + if (data < 0) > + return -ENOMEM; > + > + /* Have some data, return. */ > + if (data) > + return data; > + > +out: > + finish_wait(sk_sleep(sk), wait); > + return err; > +}I agree with Stefanos suggestion to get rid of the out: part and just have the single finish_wait().> + > static int > vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, > int flags) > @@ -1912,85 +1977,34 @@ vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, > > > while (1) { > - s64 ready; > + ssize_t read; > > - prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); > - ready = vsock_stream_has_data(vsk); > - > - if (ready == 0) { > - if (sk->sk_err != 0 || > - (sk->sk_shutdown & RCV_SHUTDOWN) || > - (vsk->peer_shutdown & SEND_SHUTDOWN)) { > - finish_wait(sk_sleep(sk), &wait); > - break; > - } > - /* Don't wait for non-blocking sockets. */ > - if (timeout == 0) { > - err = -EAGAIN; > - finish_wait(sk_sleep(sk), &wait); > - break; > - } > - > - err = transport->notify_recv_pre_block( > - vsk, target, &recv_data); > - if (err < 0) { > - finish_wait(sk_sleep(sk), &wait); > - break; > - } > - 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); > - break; > - } else if (timeout == 0) { > - err = -EAGAIN; > - finish_wait(sk_sleep(sk), &wait); > - break; > - } > - } else { > - ssize_t read; > + err = vsock_wait_data(sk, &wait, timeout, &recv_data, target); > + if (err <= 0) > + break;There is a small change in the behaviour here if vsock_stream_has_data(vsk) returned something < 0. Since you just do a break, the err value can be updated if there is an sk->sk_err, a receive shutdown has been performed or data has already been copied. That should be ok, though.> - finish_wait(sk_sleep(sk), &wait); > - > - if (ready < 0) { > - /* Invalid queue pair content. XXX This should > - * be changed to a connection reset in a later > - * change. > - */ > - > - err = -ENOMEM; > - goto out; > - } > - > - err = transport->notify_recv_pre_dequeue( > - vsk, target, &recv_data); > - if (err < 0) > - break; > + err = transport->notify_recv_pre_dequeue(vsk, target, > + &recv_data); > + if (err < 0) > + break; > > - read = transport->stream_dequeue( > - vsk, msg, > - len - copied, flags); > - if (read < 0) { > - err = -ENOMEM; > - break; > - } > + read = transport->stream_dequeue(vsk, msg, len - copied, flags); > + if (read < 0) { > + err = -ENOMEM; > + break; > + } > > - copied += read; > + copied += read; > > - err = transport->notify_recv_post_dequeue( > - vsk, target, read, > - !(flags & MSG_PEEK), &recv_data); > - if (err < 0) > - goto out; > + err = transport->notify_recv_post_dequeue(vsk, target, read, > + !(flags & MSG_PEEK), &recv_data); > + if (err < 0) > + goto out; > > - if (read >= target || flags & MSG_PEEK) > - break; > + if (read >= target || flags & MSG_PEEK) > + break; > > - target -= read; > - } > + target -= read; > } > > if (sk->sk_err) > -- > 2.25.1 >