Re: [RFC PATCH v1 08/16] af_vsock: change SEQPACKET receive loop

From: Stefano Garzarella
Date: Wed Jun 30 2021 - 08:12:20 EST


On Mon, Jun 28, 2021 at 01:03:28PM +0300, Arseny Krasnov wrote:
>Receive "loop" now really loop: it reads fragments one by
>one, sleeping if queue is empty.
>
>NOTE: 'msg_ready' pointer is not passed to 'seqpacket_dequeue()'
>here - it change callback interface, so it is moved to next patch.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@xxxxxxxxxxxxx>
>---
> net/vmw_vsock/af_vsock.c | 31 ++++++++++++++++++++++---------
> 1 file changed, 22 insertions(+), 9 deletions(-)

I think you can merge patches 8, 9, and 10 together since we
are touching the seqpacket_dequeue() behaviour.

Then you can remove in separate patches the unneeded parts (e.g.
seqpacket_has_data, msg_count, etc.).

Thanks,
Stefano

>
>diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>index 59ce35da2e5b..9552f05119f2 100644
>--- a/net/vmw_vsock/af_vsock.c
>+++ b/net/vmw_vsock/af_vsock.c
>@@ -2003,6 +2003,7 @@ static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,
> size_t len, int flags)
> {
> const struct vsock_transport *transport;
>+ bool msg_ready;
> struct vsock_sock *vsk;
> ssize_t record_len;
> long timeout;
>@@ -2013,23 +2014,36 @@ static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,
> transport = vsk->transport;
>
> timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
>+ msg_ready = false;
>+ record_len = 0;
>
>- err = vsock_connectible_wait_data(sk, &wait, timeout, NULL, 0);
>- if (err <= 0)
>- goto out;
>+ while (!msg_ready) {
>+ ssize_t fragment_len;
>+ int intr_err;
>
>- record_len = transport->seqpacket_dequeue(vsk, msg, flags);
>+ intr_err = vsock_connectible_wait_data(sk, &wait, timeout, NULL, 0);
>+ if (intr_err <= 0) {
>+ err = intr_err;
>+ break;
>+ }
>
>- if (record_len < 0) {
>- err = -ENOMEM;
>- goto out;
>+ fragment_len = transport->seqpacket_dequeue(vsk, msg, flags);
>+
>+ if (fragment_len < 0) {
>+ err = -ENOMEM;
>+ break;
>+ }
>+
>+ record_len += fragment_len;
> }
>
> if (sk->sk_err) {
> err = -sk->sk_err;
> } else if (sk->sk_shutdown & RCV_SHUTDOWN) {
> err = 0;
>- } else {
>+ }
>+
>+ if (msg_ready && !err) {
> /* User sets MSG_TRUNC, so return real length of
> * packet.
> */
>@@ -2045,7 +2059,6 @@ static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,
> msg->msg_flags |= MSG_TRUNC;
> }
>
>-out:
> return err;
> }
>
>--
>2.25.1
>