Stefano Garzarella
2021-Mar-12 15:17 UTC
[RFC PATCH v6 04/22] af_vsock: implement SEQPACKET receive loop
On Sun, Mar 07, 2021 at 08:59:45PM +0300, Arseny Krasnov wrote:>This adds receive loop for SEQPACKET. It looks like receive loop for >STREAM, but there is a little bit difference: >1) It doesn't call notify callbacks. >2) It doesn't care about 'SO_SNDLOWAT' and 'SO_RCVLOWAT' values, because > there is no sense for these values in SEQPACKET case. >3) It waits until whole record is received or error is found during > receiving. >4) It processes and sets 'MSG_TRUNC' flag. > >So to avoid extra conditions for two types of socket inside one loop, two >independent functions were created. > >Signed-off-by: Arseny Krasnov <arseny.krasnov at kaspersky.com> >--- > include/net/af_vsock.h | 5 +++ > net/vmw_vsock/af_vsock.c | 95 +++++++++++++++++++++++++++++++++++++++- > 2 files changed, 99 insertions(+), 1 deletion(-) > >diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h >index b1c717286993..5ad7ee7f78fd 100644 >--- a/include/net/af_vsock.h >+++ b/include/net/af_vsock.h >@@ -135,6 +135,11 @@ struct vsock_transport { > bool (*stream_is_active)(struct vsock_sock *); > bool (*stream_allow)(u32 cid, u32 port); > >+ /* SEQ_PACKET. */ >+ size_t (*seqpacket_seq_get_len)(struct vsock_sock *vsk); >+ int (*seqpacket_dequeue)(struct vsock_sock *vsk, struct msghdr *msg, >+ int flags, bool *msg_ready); >+ > /* Notification. */ > int (*notify_poll_in)(struct vsock_sock *, size_t, bool *); > int (*notify_poll_out)(struct vsock_sock *, size_t, bool *); >diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c >index 0bc661e54262..ac2f69362f2e 100644 >--- a/net/vmw_vsock/af_vsock.c >+++ b/net/vmw_vsock/af_vsock.c >@@ -1973,6 +1973,96 @@ static int __vsock_stream_recvmsg(struct sock *sk, struct msghdr *msg, > return err; > } > >+static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg, >+ size_t len, int flags) >+{ >+ const struct vsock_transport *transport; >+ const struct iovec *orig_iov; >+ unsigned long orig_nr_segs; >+ bool msg_ready; >+ struct vsock_sock *vsk; >+ size_t record_len; >+ long timeout; >+ int err = 0; >+ DEFINE_WAIT(wait); >+ >+ vsk = vsock_sk(sk); >+ transport = vsk->transport; >+ >+ timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); >+ orig_nr_segs = msg->msg_iter.nr_segs; >+ orig_iov = msg->msg_iter.iov; >+ msg_ready = false; >+ record_len = 0; >+ >+ while (1) { >+ err = vsock_wait_data(sk, &wait, timeout, NULL, 0); >+ >+ if (err <= 0) { >+ /* In case of any loop break(timeout, signal >+ * interrupt or shutdown), we report user that >+ * nothing was copied. >+ */ >+ err = 0; >+ break; >+ } >+ >+ if (record_len == 0) { >+ record_len >+ transport->seqpacket_seq_get_len(vsk); >+ >+ if (record_len == 0) >+ continue; >+ } >+ >+ err = transport->seqpacket_dequeue(vsk, msg, flags, &msg_ready);In order to simplify the transport interface, can we do the work of seqpacket_seq_get_len() at the beginning of seqpacket_dequeue()? So in this way seqpacket_dequeue() can return the 'record_len' or an error.