Thread (26 messages) 26 messages, 2 authors, 2021-06-30

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

From: Stefano Garzarella <sgarzare@redhat.com>
Date: 2021-06-30 12:12:20
Also in: kvm, lkml, virtualization

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 <redacted>
---
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
quoted hunk ↗ jump to hunk
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
  
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