Stefano Garzarella
2021-Jan-18 15:04 UTC
[RFC PATCH v2 02/13] af_vsock: separate rx loops for STREAM/SEQPACKET.
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 at 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 >