Stefano Garzarella
2021-Feb-11 11:47 UTC
[RFC PATCH v4 04/17] af_vsock: implement SEQPACKET receive loop
On Sun, Feb 07, 2021 at 06:15:22PM +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 | 96 +++++++++++++++++++++++++++++++++++++++- > 2 files changed, 100 insertions(+), 1 deletion(-) > >diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h >index b1c717286993..bb6a0e52be86 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 *); >+ int (*seqpacket_dequeue)(struct vsock_sock *, struct msghdr *, >+ int flags, bool *msg_ready);CHECK: Alignment should match open parenthesis #35: FILE: include/net/af_vsock.h:141: + int (*seqpacket_dequeue)(struct vsock_sock *, struct msghdr *, + int flags, bool *msg_ready); And to make checkpatch.pl happy please use the identifier name also for the others parameter. I know we haven't done this before, but for new code I think we can do it.>+ > /* 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 66c8a932f49b..3d8af987216a 100644 >--- a/net/vmw_vsock/af_vsock.c >+++ b/net/vmw_vsock/af_vsock.c >@@ -1977,6 +1977,97 @@ 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);A single line here should be okay.>+ if (err < 0) { >+ if (err == -EAGAIN) { >+ iov_iter_init(&msg->msg_iter, READ, >+ orig_iov, orig_nr_segs, >+ len); >+ /* Clear 'MSG_EOR' here, because dequeue >+ * callback above set it again if it was >+ * set by sender. This 'MSG_EOR' is from >+ * dropped record. >+ */ >+ msg->msg_flags &= ~MSG_EOR; >+ record_len = 0; >+ continue; >+ } >+ >+ err = -ENOMEM; >+ break; >+ } >+ >+ if (msg_ready) >+ break; >+ } >+ >+ if (sk->sk_err) >+ err = -sk->sk_err; >+ else if (sk->sk_shutdown & RCV_SHUTDOWN) >+ err = 0; >+ >+ if (msg_ready) { >+ /* User sets MSG_TRUNC, so return real length of >+ * packet. >+ */ >+ if (flags & MSG_TRUNC) >+ err = record_len; >+ else >+ err = len - msg->msg_iter.count; >+ >+ /* Always set MSG_TRUNC if real length of packet is >+ * bigger than user's buffer. >+ */ >+ if (record_len > len) >+ msg->msg_flags |= MSG_TRUNC; >+ } >+ >+ return err; >+} >+ > static int > vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, > int flags) >@@ -2032,7 +2123,10 @@ vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, > goto out; > } > >- err = __vsock_stream_recvmsg(sk, msg, len, flags); >+ if (sk->sk_type == SOCK_STREAM) >+ err = __vsock_stream_recvmsg(sk, msg, len, flags); >+ else >+ err = __vsock_seqpacket_recvmsg(sk, msg, len, flags); > > out: > release_sock(sk);The rest seems ok to me, but I need to get more familiar with SEQPACKET before giving my R-b. Thanks, Stefano