Re: [RFC PATCH v4 02/17] af_vsock: separate wait data loop
From: Jorgen Hansen <hidden>
Date: 2021-02-11 15:35:58
Also in:
kvm, lkml, virtualization
quoted hunk ↗ jump to hunk
On 7 Feb 2021, at 16:14, Arseny Krasnov [off-list ref] 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 <redacted> --- 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().
quoted hunk ↗ jump to hunk
+ 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