Re: [RFC PATCH v2 01/13] af_vsock: implement 'vsock_wait_data()'.

Re: [RFC PATCH v2 01/13] af_vsock: implement 'vsock_wait_data()'.

[Stefano Garzarella]

On Fri, Jan 15, 2021 at 08:40:25AM +0300, Arseny Krasnov wrote:
>This adds 'vsock_wait_data()' function which is called from user's read
>syscall and waits until new socket data is arrived. It was based on code
>from stream dequeue logic and moved to separate function because it will
>be called both from SOCK_STREAM and SOCK_SEQPACKET receive loops.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> net/vmw_vsock/af_vsock.c | 47 ++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 47 insertions(+)
>
>diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>index b12d3a322242..af716f5a93a4 100644
>--- a/net/vmw_vsock/af_vsock.c
>+++ b/net/vmw_vsock/af_vsock.c
>@@ -1822,6 +1822,53 @@ static int vsock_stream_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)
>+{
>+	int err = 0;
>+	struct vsock_sock *vsk;
>+	const struct vsock_transport *transport;

Please be sure that here and in all of the next patches, you follow the 
"Reverse Christmas tree" rule followed in net/ for the local variable 
declarations (order variable declaration lines longest to shortest).

>+
>+	vsk = vsock_sk(sk);
>+	transport = vsk->transport;
>+
>+	if (sk->sk_err != 0 ||
>+	    (sk->sk_shutdown & RCV_SHUTDOWN) ||
>+	    (vsk->peer_shutdown & SEND_SHUTDOWN)) {
>+		finish_wait(sk_sleep(sk), wait);
>+		return -1;
>+	}
>+	/* Don't wait for non-blocking sockets. */
>+	if (timeout == 0) {
>+		err = -EAGAIN;
>+		finish_wait(sk_sleep(sk), wait);
>+		return err;
>+	}
>+
>+	if (recv_data) {
>+		err = transport->notify_recv_pre_block(vsk, target, recv_data);
>+		if (err < 0) {
>+			finish_wait(sk_sleep(sk), wait);
>+			return err;
>+		}
>+	}
>+
>+	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);
>+	} else if (timeout == 0) {
>+		err = -EAGAIN;
>+		finish_wait(sk_sleep(sk), wait);
>+	}
>+

Since we are calling finish_wait() before return in all path, why not 
doing somethig like this:

out:
	finish_wait(sk_sleep(sk), wait);
>+	return err;
>+}

Then in the error paths you can do:

	err = XXX;
	goto out;

Thanks,
Stefano

>
> static int
> vsock_stream_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
>-- 
>2.25.1
>

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Re: [RFC PATCH v2 02/13] af_vsock: separate rx loops for STREAM/SEQPACKET.

[Stefano Garzarella]

On Fri, Jan 15, 2021 at 08:40:50AM +0300, Arseny Krasnov wrote:
>This adds two receive loops: for SOCK_STREAM and SOCK_SEQPACKET. Both are
>look like twins, but SEQPACKET is a little bit different from STREAM:
>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 on loop, two
>independent functions were created.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> include/net/af_vsock.h   |   5 +
> net/vmw_vsock/af_vsock.c | 202 +++++++++++++++++++++++++++++++++++++++
> 2 files changed, 207 insertions(+)
>
>diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
>index b1c717286993..46073842d489 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 *);
>+	ssize_t (*seqpacket_dequeue)(struct vsock_sock *, struct msghdr *,
>+				     size_t len, int flags);
>+
> 	/* 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 af716f5a93a4..afacbe9f4231 100644
>--- a/net/vmw_vsock/af_vsock.c
>+++ b/net/vmw_vsock/af_vsock.c
>@@ -1870,6 +1870,208 @@ static int vsock_wait_data(struct sock *sk, struct wait_queue_entry *wait,
> 	return err;
> }
>
>+static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,
>+				     size_t len, int flags)
>+{
>+	int err = 0;
>+	size_t record_len;
>+	struct vsock_sock *vsk;
>+	const struct vsock_transport *transport;
>+	long timeout;
>+	ssize_t dequeued_total = 0;
>+	unsigned long orig_nr_segs;
>+	const struct iovec *orig_iov;
>+	DEFINE_WAIT(wait);
>+
>+	vsk = vsock_sk(sk);
>+	transport = vsk->transport;
>+
>+	timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
>+	msg->msg_flags &= ~MSG_EOR;
>+	orig_nr_segs = msg->msg_iter.nr_segs;
>+	orig_iov = msg->msg_iter.iov;
>+
>+	while (1) {
>+		s64 ready;
>+
>+		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
>+		ready = vsock_stream_has_data(vsk);
>+
>+		if (ready == 0) {
>+			if (vsock_wait_data(sk, &wait, timeout, NULL, 0)) {
>+				/* In case of any loop break(timeout, signal
>+				 * interrupt or shutdown), we report user that
>+				 * nothing was copied.
>+				 */
>+				dequeued_total = 0;
>+				break;
>+			}

Maybe here we can do 'continue', remove the next line, and reduce the 
indentation on the next block.

>+		} else {
>+			ssize_t dequeued;
>+
>+			finish_wait(sk_sleep(sk), &wait);
>+
>+			if (ready < 0) {
>+				err = -ENOMEM;
>+				goto out;
>+			}
>+
>+			if (dequeued_total == 0) {
>+				record_len =
>+					transport->seqpacket_seq_get_len(vsk);
>+
>+				if (record_len == 0)
>+					continue;
>+			}
>+
>+			/* 'msg_iter.count' is number of unused bytes in iov.
>+			 * On every copy to iov iterator it is decremented at
>+			 * size of data.
>+			 */
>+			dequeued = transport->seqpacket_dequeue(vsk, msg,
>+						msg->msg_iter.count, flags);
>+
>+			if (dequeued < 0) {
>+				dequeued_total = 0;
>+
>+				if (dequeued == -EAGAIN) {
>+					iov_iter_init(&msg->msg_iter, READ,
>+						      orig_iov, orig_nr_segs,
>+						      len);
>+					msg->msg_flags &= ~MSG_EOR;
>+					continue;
>+				}
>+
>+				err = -ENOMEM;
>+				break;
>+			}
>+
>+			dequeued_total += dequeued;
>+
>+			if (dequeued_total >= record_len)
>+				break;
>+		}
>+	}
>+	if (sk->sk_err)
>+		err = -sk->sk_err;
>+	else if (sk->sk_shutdown & RCV_SHUTDOWN)
>+		err = 0;
>+
>+	if (dequeued_total > 0) {
>+		/* 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 that user buffer.
>+		 */
>+		if (record_len > len)
>+			msg->msg_flags |= MSG_TRUNC;
>+	}
>+out:
>+	return err;
>+}
>+
>+static int __vsock_stream_recvmsg(struct sock *sk, struct msghdr *msg,
>+				  size_t len, int flags)
>+{
>+	int err;
>+	const struct vsock_transport *transport;
>+	struct vsock_sock *vsk;
>+	size_t target;
>+	struct vsock_transport_recv_notify_data recv_data;
>+	long timeout;
>+	ssize_t copied;
>+
>+	DEFINE_WAIT(wait);
>+
>+	vsk = vsock_sk(sk);
>+	transport = vsk->transport;
>+
>+	/* We must not copy less than target bytes into the user's buffer
>+	 * before returning successfully, so we wait for the consume queue to
>+	 * have that much data to consume before dequeueing.  Note that this
>+	 * makes it impossible to handle cases where target is greater than the
>+	 * queue size.
>+	 */
>+	target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
>+	if (target >= transport->stream_rcvhiwat(vsk)) {
>+		err = -ENOMEM;
>+		goto out;
>+	}
>+	timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
>+	copied = 0;
>+
>+	err = transport->notify_recv_init(vsk, target, &recv_data);
>+	if (err < 0)
>+		goto out;
>+
>+	while (1) {
>+		s64 ready;
>+
>+		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
>+		ready = vsock_stream_has_data(vsk);
>+
>+		if (ready == 0) {
>+			if (vsock_wait_data(sk, &wait, timeout, 
>&recv_data, target))
>+				break;

The same also here.

>+		} else {
>+			ssize_t read;
>+
>+			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;
>+			read = transport->stream_dequeue(vsk, msg, len - copied, flags);
>+
>+			if (read < 0) {
>+				err = -ENOMEM;
>+				break;
>+			}
>+
>+			copied += read;
>+
>+			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;
>+
>+			target -= read;
>+		}
>+	}
>+
>+	if (sk->sk_err)
>+		err = -sk->sk_err;
>+	else if (sk->sk_shutdown & RCV_SHUTDOWN)
>+		err = 0;
>+	if (copied > 0)
>+		err = copied;
>+
>+out:
>+	release_sock(sk);
>+	return err;
>+}
>+
> static int
> vsock_stream_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
> 		     int flags)
>-- 
>2.25.1
>

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Re: [RFC PATCH v2 06/13] af_vsock: general support of SOCK_SEQPACKET type.

[Stefano Garzarella]

On Fri, Jan 15, 2021 at 08:42:43AM +0300, Arseny Krasnov wrote:
>This adds socket operations for SOCK_SEQPACKET and adds this type of
>socket for conditions where SOCK_STREAM is involved because both type of
>sockets are connect oriented.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> net/vmw_vsock/af_vsock.c | 108 +++++++++++++++++++++++++++++++++------
> 1 file changed, 92 insertions(+), 16 deletions(-)
>
>diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>index 4a7cdf7756c0..d0ef066e9352 100644
>--- a/net/vmw_vsock/af_vsock.c
>+++ b/net/vmw_vsock/af_vsock.c
>@@ -452,6 +452,7 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk)
> 		new_transport = transport_dgram;
> 		break;
> 	case SOCK_STREAM:
>+	case SOCK_SEQPACKET:
> 		if (vsock_use_local_transport(remote_cid))
> 			new_transport = transport_local;
> 		else if (remote_cid <= VMADDR_CID_HOST || !transport_h2g ||
>@@ -459,6 +460,13 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk)
> 			new_transport = transport_g2h;
> 		else
> 			new_transport = transport_h2g;
>+
>+		if (sk->sk_type == SOCK_SEQPACKET) {
>+			if (!new_transport->seqpacket_seq_send_len ||
>+			    !new_transport->seqpacket_seq_get_len ||
>+			    !new_transport->seqpacket_dequeue)
>+				return -ENODEV;
>+		}
> 		break;
> 	default:
> 		return -ESOCKTNOSUPPORT;
>@@ -604,8 +612,8 @@ static void vsock_pending_work(struct work_struct *work)
>
> /**** SOCKET OPERATIONS ****/
>
>-static int __vsock_bind_stream(struct vsock_sock *vsk,
>-			       struct sockaddr_vm *addr)
>+static int __vsock_bind_connectible(struct vsock_sock *vsk,
>+				    struct sockaddr_vm *addr)
> {
> 	static u32 port;
> 	struct sockaddr_vm new_addr;
>@@ -684,8 +692,9 @@ static int __vsock_bind(struct sock *sk, struct sockaddr_vm *addr)
>
> 	switch (sk->sk_socket->type) {
> 	case SOCK_STREAM:
>+	case SOCK_SEQPACKET:
> 		spin_lock_bh(&vsock_table_lock);
>-		retval = __vsock_bind_stream(vsk, addr);
>+		retval = __vsock_bind_connectible(vsk, addr);
> 		spin_unlock_bh(&vsock_table_lock);
> 		break;
>
>@@ -767,6 +776,11 @@ static struct sock *__vsock_create(struct net *net,
> 	return sk;
> }
>
>+static bool sock_type_connectible(u16 type)
>+{
>+	return (type == SOCK_STREAM || type == SOCK_SEQPACKET);
>+}
>+
> static void __vsock_release(struct sock *sk, int level)
> {
> 	if (sk) {
>@@ -785,7 +799,7 @@ static void __vsock_release(struct sock *sk, int level)
>
> 		if (vsk->transport)
> 			vsk->transport->release(vsk);
>-		else if (sk->sk_type == SOCK_STREAM)
>+		else if (sock_type_connectible(sk->sk_type))
> 			vsock_remove_sock(vsk);
>
> 		sock_orphan(sk);
>@@ -945,7 +959,7 @@ static int vsock_shutdown(struct socket *sock, int mode)
> 	sk = sock->sk;
> 	if (sock->state == SS_UNCONNECTED) {
> 		err = -ENOTCONN;
>-		if (sk->sk_type == SOCK_STREAM)
>+		if (sock_type_connectible(sk->sk_type))
> 			return err;
> 	} else {
> 		sock->state = SS_DISCONNECTING;
>@@ -960,7 +974,7 @@ static int vsock_shutdown(struct socket *sock, int mode)
> 		sk->sk_state_change(sk);
> 		release_sock(sk);
>
>-		if (sk->sk_type == SOCK_STREAM) {
>+		if (sock_type_connectible(sk->sk_type)) {
> 			sock_reset_flag(sk, SOCK_DONE);
> 			vsock_send_shutdown(sk, mode);
> 		}
>@@ -1013,7 +1027,7 @@ static __poll_t vsock_poll(struct file *file, struct socket *sock,
> 		if (!(sk->sk_shutdown & SEND_SHUTDOWN))
> 			mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
>
>-	} else if (sock->type == SOCK_STREAM) {
>+	} else if (sock_type_connectible(sk->sk_type)) {
> 		const struct vsock_transport *transport = vsk->transport;
> 		lock_sock(sk);
>
>@@ -1259,8 +1273,8 @@ static void vsock_connect_timeout(struct work_struct *work)
> 	sock_put(sk);
> }
>
>-static int vsock_stream_connect(struct socket *sock, struct sockaddr *addr,
>-				int addr_len, int flags)
>+static int vsock_connect(struct socket *sock, struct sockaddr *addr,
>+			 int addr_len, int flags)
> {
> 	int err;
> 	struct sock *sk;
>@@ -1410,7 +1424,7 @@ static int vsock_accept(struct socket *sock, struct socket *newsock, int flags,
>
> 	lock_sock(listener);
>
>-	if (sock->type != SOCK_STREAM) {
>+	if (!sock_type_connectible(sock->type)) {
> 		err = -EOPNOTSUPP;
> 		goto out;
> 	}
>@@ -1477,6 +1491,18 @@ static int vsock_accept(struct socket *sock, struct socket *newsock, int flags,
> 	return err;
> }
>
>+static int vsock_stream_connect(struct socket *sock, struct sockaddr *addr,
>+				int addr_len, int flags)
>+{
>+	return vsock_connect(sock, addr, addr_len, flags);
>+}
>+
>+static int vsock_seqpacket_connect(struct socket *sock, struct sockaddr *addr,
>+				   int addr_len, int flags)
>+{
>+	return vsock_connect(sock, addr, addr_len, flags);
>+}
>+
> static int vsock_listen(struct socket *sock, int backlog)
> {
> 	int err;
>@@ -1487,7 +1513,7 @@ static int vsock_listen(struct socket *sock, int backlog)
>
> 	lock_sock(sk);
>
>-	if (sock->type != SOCK_STREAM) {
>+	if (!sock_type_connectible(sk->sk_type)) {
> 		err = -EOPNOTSUPP;
> 		goto out;
> 	}
>@@ -1531,11 +1557,11 @@ static void vsock_update_buffer_size(struct vsock_sock *vsk,
> 	vsk->buffer_size = val;
> }
>
>-static int vsock_stream_setsockopt(struct socket *sock,
>-				   int level,
>-				   int optname,
>-				   sockptr_t optval,
>-				   unsigned int optlen)
>+static int vsock_setsockopt(struct socket *sock,
>+			    int level,
>+			    int optname,
>+			    sockptr_t optval,
>+			    unsigned int optlen)
> {
> 	int err;
> 	struct sock *sk;
>@@ -1612,6 +1638,24 @@ static int vsock_stream_setsockopt(struct socket *sock,
> 	return err;
> }
>
>+static int vsock_seqpacket_setsockopt(struct socket *sock,
>+				      int level,
>+				      int optname,
>+				      sockptr_t optval,
>+				      unsigned int optlen)
>+{
>+	return vsock_setsockopt(sock, level, optname, optval, optlen);
>+}
>+
>+static int vsock_stream_setsockopt(struct socket *sock,
>+				   int level,
>+				   int optname,
>+				   sockptr_t optval,
>+				   unsigned int optlen)
>+{
>+	return vsock_setsockopt(sock, level, optname, optval, optlen);
>+}
>+
> static int vsock_stream_getsockopt(struct socket *sock,
> 				   int level, int optname,
> 				   char __user *optval,
>@@ -1683,6 +1727,14 @@ static int vsock_stream_getsockopt(struct socket *sock,
> 	return 0;
> }
>
>+static int vsock_seqpacket_getsockopt(struct socket *sock,
>+				      int level, int optname,
>+				      char __user *optval,
>+				      int __user *optlen)
>+{
>+	return vsock_stream_getsockopt(sock, level, optname, optval, optlen);
>+}
>+

Why didn't you do the same thing you did with setsockopt?

Both are fine for me, but I'd like to do the same thing for getsockopt 
and setsockopt.

If you opt to create new functions, maybe it's better to call them 
vsock_connectible_*sockopt()

> static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,
> 				     size_t len)
> {
>@@ -2184,6 +2236,27 @@ static const struct proto_ops vsock_stream_ops = {
> 	.sendpage = sock_no_sendpage,
> };
>
>+static const struct proto_ops vsock_seqpacket_ops = {
>+	.family = PF_VSOCK,
>+	.owner = THIS_MODULE,
>+	.release = vsock_release,
>+	.bind = vsock_bind,
>+	.connect = vsock_seqpacket_connect,
>+	.socketpair = sock_no_socketpair,
>+	.accept = vsock_accept,
>+	.getname = vsock_getname,
>+	.poll = vsock_poll,
>+	.ioctl = sock_no_ioctl,
>+	.listen = vsock_listen,
>+	.shutdown = vsock_shutdown,
>+	.setsockopt = vsock_seqpacket_setsockopt,
>+	.getsockopt = vsock_seqpacket_getsockopt,
>+	.sendmsg = vsock_seqpacket_sendmsg,
>+	.recvmsg = vsock_seqpacket_recvmsg,
>+	.mmap = sock_no_mmap,
>+	.sendpage = sock_no_sendpage,
>+};
>+
> static int vsock_create(struct net *net, struct socket *sock,
> 			int protocol, int kern)
> {
>@@ -2204,6 +2277,9 @@ static int vsock_create(struct net *net, struct socket *sock,
> 	case SOCK_STREAM:
> 		sock->ops = &vsock_stream_ops;
> 		break;
>+	case SOCK_SEQPACKET:
>+		sock->ops = &vsock_seqpacket_ops;
>+		break;
> 	default:
> 		return -ESOCKTNOSUPPORT;
> 	}
>-- 
>2.25.1
>

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Re: [RFC PATCH v2 08/13] virtio/vsock: dequeue callback for SOCK_SEQPACKET.

[Stefano Garzarella]

On Fri, Jan 15, 2021 at 08:43:24AM +0300, Arseny Krasnov wrote:
>This adds transport callback and it's logic for SEQPACKET dequeue.
>Callback fetches RW packets from rx queue of socket until whole record
>is copied(if user's buffer is full, user is not woken up). This is done
>to not stall sender, because if we wake up user and it leaves syscall,
>nobody will send credit update for rest of record, and sender will wait
>for next enter of read syscall at receiver's side. So if user buffer is
>full, we just send credit update and drop data. If during copy SEQ_BEGIN
>was found(and not all data was copied), copying is restarted by reset
>user's iov iterator(previous unfinished data is dropped).
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> include/linux/virtio_vsock.h            |   4 +
> include/uapi/linux/virtio_vsock.h       |   9 ++
> net/vmw_vsock/virtio_transport_common.c | 128 ++++++++++++++++++++++++
> 3 files changed, 141 insertions(+)
>
>diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>index dc636b727179..7f0ef5204e33 100644
>--- a/include/linux/virtio_vsock.h
>+++ b/include/linux/virtio_vsock.h
>@@ -36,6 +36,10 @@ struct virtio_vsock_sock {
> 	u32 rx_bytes;
> 	u32 buf_alloc;
> 	struct list_head rx_queue;
>+
>+	/* For SOCK_SEQPACKET */
>+	u32 user_read_seq_len;
>+	u32 user_read_copied;
> };
>
> struct virtio_vsock_pkt {
>diff --git a/include/uapi/linux/virtio_vsock.h b/include/uapi/linux/virtio_vsock.h
>index 1d57ed3d84d2..058908bc19fc 100644
>--- a/include/uapi/linux/virtio_vsock.h
>+++ b/include/uapi/linux/virtio_vsock.h
>@@ -65,6 +65,7 @@ struct virtio_vsock_hdr {
>
> enum virtio_vsock_type {
> 	VIRTIO_VSOCK_TYPE_STREAM = 1,
>+	VIRTIO_VSOCK_TYPE_SEQPACKET = 2,
> };
>
> enum virtio_vsock_op {
>@@ -83,6 +84,9 @@ enum virtio_vsock_op {
> 	VIRTIO_VSOCK_OP_CREDIT_UPDATE = 6,
> 	/* Request the peer to send the credit info to us */
> 	VIRTIO_VSOCK_OP_CREDIT_REQUEST = 7,
>+
>+	/* Record begin for SOCK_SEQPACKET */
>+	VIRTIO_VSOCK_OP_SEQ_BEGIN = 8,
> };
>
> /* VIRTIO_VSOCK_OP_SHUTDOWN flags values */
>@@ -91,4 +95,9 @@ enum virtio_vsock_shutdown {
> 	VIRTIO_VSOCK_SHUTDOWN_SEND = 2,
> };
>
>+/* VIRTIO_VSOCK_OP_RW flags values for SOCK_SEQPACKET type */
>+enum virtio_vsock_rw_seqpacket {
>+	VIRTIO_VSOCK_RW_EOR = 1,
>+};
>+
> #endif /* _UAPI_LINUX_VIRTIO_VSOCK_H */
>diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>index 5956939eebb7..4328f653a477 100644
>--- a/net/vmw_vsock/virtio_transport_common.c
>+++ b/net/vmw_vsock/virtio_transport_common.c
>@@ -397,6 +397,132 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
> 	return err;
> }
>
>+static inline void virtio_transport_del_n_free_pkt(struct virtio_vsock_pkt *pkt)
>+{
>+	list_del(&pkt->list);
>+	virtio_transport_free_pkt(pkt);
>+}
>+
>+static size_t virtio_transport_drop_until_seq_begin(struct virtio_vsock_sock *vvs)
>+{
>+	struct virtio_vsock_pkt *pkt, *n;
>+	size_t bytes_dropped = 0;
>+
>+	list_for_each_entry_safe(pkt, n, &vvs->rx_queue, list) {
>+		if (le16_to_cpu(pkt->hdr.op) == VIRTIO_VSOCK_OP_SEQ_BEGIN)
>+			break;
>+
>+		bytes_dropped += le32_to_cpu(pkt->hdr.len);
>+		virtio_transport_dec_rx_pkt(vvs, pkt);
>+		virtio_transport_del_n_free_pkt(pkt);
>+	}
>+
>+	return bytes_dropped;
>+}
>+
>+static ssize_t virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
>+						     struct msghdr *msg,
>+						     size_t user_buf_len)
>+{
>+	struct virtio_vsock_sock *vvs = vsk->trans;
>+	struct virtio_vsock_pkt *pkt;
>+	size_t bytes_handled = 0;
>+	int err = 0;
>+
>+	spin_lock_bh(&vvs->rx_lock);
>+
>+	if (user_buf_len == 0) {
>+		/* User's buffer is full, we processing rest of
>+		 * record and drop it. If 'SEQ_BEGIN' is found
>+		 * while iterating, user will be woken up,
>+		 * because record is already copied, and we
>+		 * don't care about absent of some tail RW packets
>+		 * of it. Return number of bytes(rest of record),
>+		 * but ignore credit update for such absent bytes.
>+		 */
>+		bytes_handled = virtio_transport_drop_until_seq_begin(vvs);
>+		vvs->user_read_copied += bytes_handled;
>+
>+		if (!list_empty(&vvs->rx_queue) &&
>+		    vvs->user_read_copied < vvs->user_read_seq_len) {
>+			/* 'SEQ_BEGIN' found, but record isn't complete.
>+			 * Set number of copied bytes to fit record size
>+			 * and force counters to finish receiving.
>+			 */
>+			bytes_handled += (vvs->user_read_seq_len - vvs->user_read_copied);
>+			vvs->user_read_copied = vvs->user_read_seq_len;
>+		}
>+	}
>+
>+	/* Now start copying. */
>+	while (vvs->user_read_copied < vvs->user_read_seq_len &&
>+	       vvs->rx_bytes &&
>+	       user_buf_len &&
>+	       !err) {
>+		pkt = list_first_entry(&vvs->rx_queue, struct virtio_vsock_pkt, list);
>+
>+		switch (le16_to_cpu(pkt->hdr.op)) {
>+		case VIRTIO_VSOCK_OP_SEQ_BEGIN: {
>+			/* Unexpected 'SEQ_BEGIN' during record copy:
>+			 * Leave receive loop, 'EAGAIN' will restart it from
>+			 * outer receive loop, packet is still in queue and
>+			 * counters are cleared. So in next loop enter,
>+			 * 'SEQ_BEGIN' will be dequeued first. User's iov
>+			 * iterator will be reset in outer loop. Also
>+			 * send credit update, because some bytes could be
>+			 * copied. User will never see unfinished record.
>+			 */
>+			err = -EAGAIN;
>+			break;
>+		}
>+		case VIRTIO_VSOCK_OP_RW: {
>+			size_t bytes_to_copy;
>+			size_t pkt_len;
>+
>+			pkt_len = (size_t)le32_to_cpu(pkt->hdr.len);
>+			bytes_to_copy = min(user_buf_len, pkt_len);
>+
>+			/* sk_lock is held by caller so no one else can dequeue.
>+			 * Unlock rx_lock since memcpy_to_msg() may sleep.
>+			 */
>+			spin_unlock_bh(&vvs->rx_lock);
>+
>+			if (memcpy_to_msg(msg, pkt->buf, bytes_to_copy)) {
>+				spin_lock_bh(&vvs->rx_lock);
>+				err = -EINVAL;
>+				break;
>+			}
>+
>+			spin_lock_bh(&vvs->rx_lock);
>+			user_buf_len -= bytes_to_copy;
>+			bytes_handled += pkt->len;
>+			vvs->user_read_copied += bytes_to_copy;
>+
>+			if (le16_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_RW_EOR)
                             ^
hdr.flags is __le32, so please use le32_to_cpu()

>+				msg->msg_flags |= MSG_EOR;
>+			break;
>+		}
>+		default:
>+			;
>+		}
>+
>+		/* For unexpected 'SEQ_BEGIN', keep such packet in queue,
>+		 * but drop any other type of packet.
>+		 */
>+		if (le16_to_cpu(pkt->hdr.op) != VIRTIO_VSOCK_OP_SEQ_BEGIN) {
>+			virtio_transport_dec_rx_pkt(vvs, pkt);
>+			virtio_transport_del_n_free_pkt(pkt);
>+		}
>+	}
>+
>+	spin_unlock_bh(&vvs->rx_lock);
>+
>+	virtio_transport_send_credit_update(vsk, VIRTIO_VSOCK_TYPE_SEQPACKET,
>+					    NULL);
>+
>+	return err ?: bytes_handled;
>+}
>+
> ssize_t
> virtio_transport_stream_dequeue(struct vsock_sock *vsk,
> 				struct msghdr *msg,
>@@ -481,6 +607,8 @@ int virtio_transport_do_socket_init(struct vsock_sock *vsk,
> 	spin_lock_init(&vvs->rx_lock);
> 	spin_lock_init(&vvs->tx_lock);
> 	INIT_LIST_HEAD(&vvs->rx_queue);
>+	vvs->user_read_copied = 0;
>+	vvs->user_read_seq_len = 0;
>
> 	return 0;
> }
>-- 
>2.25.1
>

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Re: [RFC PATCH v2 10/13] virtio/vsock: update receive logic

[Stefano Garzarella]

On Fri, Jan 15, 2021 at 08:44:07AM +0300, Arseny Krasnov wrote:
>This modifies current receive logic for SEQPACKET support:
>1) Add 'SEQ_BEGIN' packet to socket's rx queue.
>2) Add 'RW' packet to rx queue, but without merging inside buffer of last
>   packet in queue.
>3) Perform check for packet type and socket type on receive(if mismatch,
>   then reset connection).
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> net/vmw_vsock/virtio_transport_common.c | 79 ++++++++++++++++++-------
> 1 file changed, 58 insertions(+), 21 deletions(-)
>
>diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>index fe1272e74517..c3e07eb1c666 100644
>--- a/net/vmw_vsock/virtio_transport_common.c
>+++ b/net/vmw_vsock/virtio_transport_common.c
>@@ -397,6 +397,14 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
> 	return err;
> }
>
>+static u16 virtio_transport_get_type(struct sock *sk)
>+{
>+	if (sk->sk_type == SOCK_STREAM)
>+		return VIRTIO_VSOCK_TYPE_STREAM;
>+	else
>+		return VIRTIO_VSOCK_TYPE_SEQPACKET;
>+}
>+
> static inline void virtio_transport_del_n_free_pkt(struct virtio_vsock_pkt *pkt)
> {
> 	list_del(&pkt->list);
>@@ -1050,39 +1058,49 @@ virtio_transport_recv_enqueue(struct vsock_sock *vsk,
> 			      struct virtio_vsock_pkt *pkt)
> {
> 	struct virtio_vsock_sock *vvs = vsk->trans;
>-	bool can_enqueue, free_pkt = false;
>+	bool free_pkt = false;
>
> 	pkt->len = le32_to_cpu(pkt->hdr.len);
> 	pkt->off = 0;
>
> 	spin_lock_bh(&vvs->rx_lock);
>
>-	can_enqueue = virtio_transport_inc_rx_pkt(vvs, pkt);
>-	if (!can_enqueue) {
>+	if (!virtio_transport_inc_rx_pkt(vvs, pkt)) {
> 		free_pkt = true;
> 		goto out;
> 	}
>
>-	/* Try to copy small packets into the buffer of last packet queued,
>-	 * to avoid wasting memory queueing the entire buffer with a small
>-	 * payload.
>-	 */
>-	if (pkt->len <= GOOD_COPY_LEN && !list_empty(&vvs->rx_queue)) {
>-		struct virtio_vsock_pkt *last_pkt;
>+	switch (le32_to_cpu(pkt->hdr.type)) {
                 ^
hdr.type is __le16, so please use le16_to_cpu()

>+	case VIRTIO_VSOCK_TYPE_STREAM: {
>+		/* Try to copy small packets into the buffer of last 
>packet queued,
>+		 * to avoid wasting memory queueing the entire buffer with a small
>+		 * payload.
>+		 */
>+		if (pkt->len <= GOOD_COPY_LEN && !list_empty(&vvs->rx_queue)) {
>+			struct virtio_vsock_pkt *last_pkt;
>
>-		last_pkt = list_last_entry(&vvs->rx_queue,
>-					   struct virtio_vsock_pkt, list);
>+			last_pkt = list_last_entry(&vvs->rx_queue,
>+						   struct virtio_vsock_pkt, list);
>
>-		/* If there is space in the last packet queued, we copy the
>-		 * new packet in its buffer.
>-		 */
>-		if (pkt->len <= last_pkt->buf_len - last_pkt->len) {
>-			memcpy(last_pkt->buf + last_pkt->len, pkt->buf,
>-			       pkt->len);
>-			last_pkt->len += pkt->len;
>-			free_pkt = true;
>-			goto out;
>+			/* If there is space in the last packet queued, we copy the
>+			 * new packet in its buffer.
>+			 */
>+			if (pkt->len <= last_pkt->buf_len - last_pkt->len) {
>+				memcpy(last_pkt->buf + last_pkt->len, pkt->buf,
>+				       pkt->len);
>+				last_pkt->len += pkt->len;
>+				free_pkt = true;
>+				goto out;
>+			}
> 		}
>+
>+		break;
>+	}
>+	case VIRTIO_VSOCK_TYPE_SEQPACKET: {
>+		break;
>+	}
>+	default:
>+		goto out;
> 	}
>
> 	list_add_tail(&pkt->list, &vvs->rx_queue);
>@@ -1101,6 +1119,14 @@ virtio_transport_recv_connected(struct sock *sk,
> 	int err = 0;
>
> 	switch (le16_to_cpu(pkt->hdr.op)) {
>+	case VIRTIO_VSOCK_OP_SEQ_BEGIN: {
>+		struct virtio_vsock_sock *vvs = vsk->trans;
>+
>+		spin_lock_bh(&vvs->rx_lock);
>+		list_add_tail(&pkt->list, &vvs->rx_queue);
>+		spin_unlock_bh(&vvs->rx_lock);
>+		return err;
>+	}
> 	case VIRTIO_VSOCK_OP_RW:
> 		virtio_transport_recv_enqueue(vsk, pkt);
> 		sk->sk_data_ready(sk);
>@@ -1247,6 +1273,12 @@ virtio_transport_recv_listen(struct sock *sk, struct virtio_vsock_pkt *pkt,
> 	return 0;
> }
>
>+static bool virtio_transport_valid_type(u16 type)
>+{
>+	return (type == VIRTIO_VSOCK_TYPE_STREAM) ||
>+	       (type == VIRTIO_VSOCK_TYPE_SEQPACKET);
>+}
>+
> /* We are under the virtio-vsock's vsock->rx_lock or vhost-vsock's vq->mutex
>  * lock.
>  */
>@@ -1272,7 +1304,7 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
> 					le32_to_cpu(pkt->hdr.buf_alloc),
> 					le32_to_cpu(pkt->hdr.fwd_cnt));
>
>-	if (le16_to_cpu(pkt->hdr.type) != VIRTIO_VSOCK_TYPE_STREAM) {
>+	if (!virtio_transport_valid_type(le16_to_cpu(pkt->hdr.type))) {
> 		(void)virtio_transport_reset_no_sock(t, pkt);
> 		goto free_pkt;
> 	}
>@@ -1289,6 +1321,11 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
> 		}
> 	}
>
>+	if (virtio_transport_get_type(sk) != le16_to_cpu(pkt->hdr.type)) {
>+		(void)virtio_transport_reset_no_sock(t, pkt);
>+		goto free_pkt;
>+	}
>+
> 	vsk = vsock_sk(sk);
>
> 	space_available = virtio_transport_space_update(sk, pkt);
>-- 
>2.25.1
>

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Re: [RFC PATCH v2 11/13] virtio/vsock: rest of SOCK_SEQPACKET support

[Stefano Garzarella]

On Fri, Jan 15, 2021 at 08:44:22AM +0300, Arseny Krasnov wrote:
>This adds rest of logic for SEQPACKET:
>1) Shared functions for packet sending now set valid type of packet
>   according socket type.
>2) SEQPACKET specific function like SEQ_BEGIN send and data dequeue.
>3) Ops for virtio transport.
>4) TAP support for SEQPACKET is not so easy if it is necessary to send
>   whole record to TAP interface. This could be done by allocating
>   new packet when whole record is received, data of record must be
>   copied to TAP packet.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> include/linux/virtio_vsock.h            |  7 ++++
> net/vmw_vsock/virtio_transport.c        |  4 ++
> net/vmw_vsock/virtio_transport_common.c | 54 ++++++++++++++++++++++---
> 3 files changed, 59 insertions(+), 6 deletions(-)
>
>diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>index af8705ea8b95..ad9783df97c9 100644
>--- a/include/linux/virtio_vsock.h
>+++ b/include/linux/virtio_vsock.h
>@@ -84,7 +84,14 @@ virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
> 			       struct msghdr *msg,
> 			       size_t len, int flags);
>
>+bool virtio_transport_seqpacket_seq_send_len(struct vsock_sock *vsk, size_t len);
> size_t virtio_transport_seqpacket_seq_get_len(struct vsock_sock *vsk);
>+ssize_t
>+virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
>+				   struct msghdr *msg,
>+				   size_t len,
>+				   int type);
>+
> s64 virtio_transport_stream_has_data(struct vsock_sock *vsk);
> s64 virtio_transport_stream_has_space(struct vsock_sock *vsk);
>
>diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
>index 2700a63ab095..5a7ab1befee8 100644
>--- a/net/vmw_vsock/virtio_transport.c
>+++ b/net/vmw_vsock/virtio_transport.c
>@@ -469,6 +469,10 @@ static struct virtio_transport virtio_transport = {
> 		.stream_is_active         = virtio_transport_stream_is_active,
> 		.stream_allow             = virtio_transport_stream_allow,
>
>+		.seqpacket_seq_send_len	  = virtio_transport_seqpacket_seq_send_len,
>+		.seqpacket_seq_get_len	  = virtio_transport_seqpacket_seq_get_len,
>+		.seqpacket_dequeue        = virtio_transport_seqpacket_dequeue,
>+
> 		.notify_poll_in           = virtio_transport_notify_poll_in,
> 		.notify_poll_out          = virtio_transport_notify_poll_out,
> 		.notify_recv_init         = virtio_transport_notify_recv_init,
>diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>index c3e07eb1c666..5fdf1adfdaab 100644
>--- a/net/vmw_vsock/virtio_transport_common.c
>+++ b/net/vmw_vsock/virtio_transport_common.c
>@@ -139,6 +139,7 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque)
> 		break;
> 	case VIRTIO_VSOCK_OP_CREDIT_UPDATE:
> 	case VIRTIO_VSOCK_OP_CREDIT_REQUEST:
>+	case VIRTIO_VSOCK_OP_SEQ_BEGIN:
> 		hdr->op = cpu_to_le16(AF_VSOCK_OP_CONTROL);
> 		break;
> 	default:
>@@ -157,6 +158,10 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque)
>
> void virtio_transport_deliver_tap_pkt(struct virtio_vsock_pkt *pkt)
> {
>+	/* TODO: implement tap support for SOCK_SEQPACKET. */
>+	if (le32_to_cpu(pkt->hdr.type) == VIRTIO_VSOCK_TYPE_SEQPACKET)
             ^
hdr.type is __le16, so please use le16_to_cpu()

>+		return;
>+
> 	if (pkt->tap_delivered)
> 		return;
>
>@@ -405,6 +410,19 @@ static u16 virtio_transport_get_type(struct sock *sk)
> 		return VIRTIO_VSOCK_TYPE_SEQPACKET;
> }
>
>+bool virtio_transport_seqpacket_seq_send_len(struct vsock_sock *vsk, size_t len)
>+{
>+	struct virtio_vsock_pkt_info info = {
>+		.type = VIRTIO_VSOCK_TYPE_SEQPACKET,
>+		.op = VIRTIO_VSOCK_OP_SEQ_BEGIN,
>+		.vsk = vsk,
>+		.flags = len
>+	};
>+
>+	return virtio_transport_send_pkt_info(vsk, &info);
>+}
>+EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_seq_send_len);
>+
> static inline void virtio_transport_del_n_free_pkt(struct virtio_vsock_pkt *pkt)
> {
> 	list_del(&pkt->list);
>@@ -576,6 +594,18 @@ virtio_transport_stream_dequeue(struct vsock_sock *vsk,
> }
> EXPORT_SYMBOL_GPL(virtio_transport_stream_dequeue);
>
>+ssize_t
>+virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
>+				   struct msghdr *msg,
>+				   size_t len, int flags)
>+{
>+	if (flags & MSG_PEEK)
>+		return -EOPNOTSUPP;
>+
>+	return virtio_transport_seqpacket_do_dequeue(vsk, msg, len);
>+}
>+EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_dequeue);
>+
> int
> virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
> 			       struct msghdr *msg,
>@@ -659,13 +689,15 @@ EXPORT_SYMBOL_GPL(virtio_transport_do_socket_init);
> void virtio_transport_notify_buffer_size(struct vsock_sock *vsk, u64 *val)
> {
> 	struct virtio_vsock_sock *vvs = vsk->trans;
>+	int type;
>
> 	if (*val > VIRTIO_VSOCK_MAX_BUF_SIZE)
> 		*val = VIRTIO_VSOCK_MAX_BUF_SIZE;
>
> 	vvs->buf_alloc = *val;
>
>-	virtio_transport_send_credit_update(vsk, VIRTIO_VSOCK_TYPE_STREAM,
>+	type = virtio_transport_get_type(sk_vsock(vsk));
>+	virtio_transport_send_credit_update(vsk, type,
> 					    NULL);

With this change, you can move 'NULL' in the previous line.

> }
> EXPORT_SYMBOL_GPL(virtio_transport_notify_buffer_size);
>@@ -793,10 +825,11 @@ int virtio_transport_connect(struct vsock_sock *vsk)
> {
> 	struct virtio_vsock_pkt_info info = {
> 		.op = VIRTIO_VSOCK_OP_REQUEST,
>-		.type = VIRTIO_VSOCK_TYPE_STREAM,
> 		.vsk = vsk,
> 	};
>
>+	info.type = virtio_transport_get_type(sk_vsock(vsk));
>+
> 	return virtio_transport_send_pkt_info(vsk, &info);
> }
> EXPORT_SYMBOL_GPL(virtio_transport_connect);
>@@ -805,7 +838,6 @@ int virtio_transport_shutdown(struct vsock_sock *vsk, int mode)
> {
> 	struct virtio_vsock_pkt_info info = {
> 		.op = VIRTIO_VSOCK_OP_SHUTDOWN,
>-		.type = VIRTIO_VSOCK_TYPE_STREAM,
> 		.flags = (mode & RCV_SHUTDOWN ?
> 			  VIRTIO_VSOCK_SHUTDOWN_RCV : 0) |
> 			 (mode & SEND_SHUTDOWN ?
>@@ -813,6 +845,8 @@ int virtio_transport_shutdown(struct vsock_sock *vsk, int mode)
> 		.vsk = vsk,
> 	};
>
>+	info.type = virtio_transport_get_type(sk_vsock(vsk));
>+
> 	return virtio_transport_send_pkt_info(vsk, &info);
> }
> EXPORT_SYMBOL_GPL(virtio_transport_shutdown);
>@@ -834,12 +868,18 @@ virtio_transport_stream_enqueue(struct vsock_sock *vsk,
> {
> 	struct virtio_vsock_pkt_info info = {
> 		.op = VIRTIO_VSOCK_OP_RW,
>-		.type = VIRTIO_VSOCK_TYPE_STREAM,
> 		.msg = msg,
> 		.pkt_len = len,
> 		.vsk = vsk,
>+		.flags = 0,
> 	};
>
>+	info.type = virtio_transport_get_type(sk_vsock(vsk));
>+
>+	if (info.type == VIRTIO_VSOCK_TYPE_SEQPACKET &&
>+	    msg->msg_flags & MSG_EOR)
>+		info.flags |= VIRTIO_VSOCK_RW_EOR;
>+
> 	return virtio_transport_send_pkt_info(vsk, &info);
> }
> EXPORT_SYMBOL_GPL(virtio_transport_stream_enqueue);
>@@ -857,7 +897,6 @@ static int virtio_transport_reset(struct vsock_sock *vsk,
> {
> 	struct virtio_vsock_pkt_info info = {
> 		.op = VIRTIO_VSOCK_OP_RST,
>-		.type = VIRTIO_VSOCK_TYPE_STREAM,
> 		.reply = !!pkt,
> 		.vsk = vsk,
> 	};
>@@ -866,6 +905,8 @@ static int virtio_transport_reset(struct vsock_sock *vsk,
> 	if (pkt && le16_to_cpu(pkt->hdr.op) == VIRTIO_VSOCK_OP_RST)
> 		return 0;
>
>+	info.type = virtio_transport_get_type(sk_vsock(vsk));
>+
> 	return virtio_transport_send_pkt_info(vsk, &info);
> }
>
>@@ -1177,13 +1218,14 @@ virtio_transport_send_response(struct vsock_sock *vsk,
> {
> 	struct virtio_vsock_pkt_info info = {
> 		.op = VIRTIO_VSOCK_OP_RESPONSE,
>-		.type = VIRTIO_VSOCK_TYPE_STREAM,
> 		.remote_cid = le64_to_cpu(pkt->hdr.src_cid),
> 		.remote_port = le32_to_cpu(pkt->hdr.src_port),
> 		.reply = true,
> 		.vsk = vsk,
> 	};
>
>+	info.type = virtio_transport_get_type(sk_vsock(vsk));
>+
> 	return virtio_transport_send_pkt_info(vsk, &info);
> }
>
>-- 
>2.25.1
>

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Re: [RFC PATCH v2 00/13] virtio/vsock: introduce SOCK_SEQPACKET support.

[Stefano Garzarella]

On Fri, Jan 15, 2021 at 12:59:30PM +0300, stsp wrote:
>15.01.2021 08:35, Arseny Krasnov пишет:
>>      This patchset impelements support of SOCK_SEQPACKET for virtio
>>transport.
>>      As SOCK_SEQPACKET guarantees to save record boundaries, so to
>>do it, new packet operation was added: it marks start of record (with
>>record length in header), such packet doesn't carry any data.  To send
>>record, packet with start marker is sent first, then all data is sent
>>as usual 'RW' packets. On receiver's side, length of record is known
>>from packet with start record marker. Now as  packets of one socket
>>are not reordered neither on vsock nor on vhost transport layers, such
>>marker allows to restore original record on receiver's side. If user's
>>buffer is smaller that
>
>than
>
>
>>  record length, when
>
>then
>
>
>>  v1 -> v2:
>>  - patches reordered: af_vsock.c changes now before virtio vsock
>>  - patches reorganized: more small patches, where +/- are not mixed
>
>If you did this because I asked, then this
>is not what I asked. :)
>You can't just add some static func in a
>separate patch, as it will just produce the
>compilation warning of an unused function.
>I only asked to separate the refactoring from
>the new code. I.e. if you move some code
>block to a separate function, you shouldn't
>split that into 2 patches, one that adds a
>code block and another one that removes it.
>It should be in one patch, so that it is clear
>what was moved, and no new warnings are
>introduced.
>What I asked to separate, is the old code
>moves with the new code additions. Such
>things can definitely go in a separate patches.

Arseny, thanks for the v2.
I appreciated that you moved the af_vsock changes before the transport
and also the test, but I agree with stsp about split patches.

As stsp suggested, you can have some "preparation" patches that touch
the already existing code (e.g. rename vsock_stream_sendmsg in
vsock_connectible_sendmsg() and call it inside the new
vsock_stream_sendmsg, etc.), then a patch that adds seqpacket stuff in
af_vsock.

Also for virtio/vhost transports, you can have some patches that add
support in virtio_transport_common, then a patch that enable it in
virtio_transport and a patch for vhost_vsock, as you rightly did in
patch 12.

So, I'd suggest moving out the code that touches virtio_transport.c
from patch 11.

These changes should simplify the review.

In addition, you can also remove the . from the commit titles.


I left other comments in the single patches.

Thanks,
Stefano

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