From: Stefano Garzarella <sgarzare@redhat.com> To: Arseny Krasnov <arseny.krasnov@kaspersky.com> Cc: Stefan Hajnoczi <stefanha@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>, Jason Wang <jasowang@redhat.com>, "David S. Miller" <davem@davemloft.net>, Jakub Kicinski <kuba@kernel.org>, Jorgen Hansen <jhansen@vmware.com>, Colin Ian King <colin.king@canonical.com>, Andra Paraschiv <andraprs@amazon.com>, Norbert Slusarek <nslusarek@gmx.net>, "kvm@vger.kernel.org" <kvm@vger.kernel.org>, "virtualization@lists.linux-foundation.org" <virtualization@lists.linux-foundation.org>, "netdev@vger.kernel.org" <netdev@vger.kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "oxffffaa@gmail.com" <oxffffaa@gmail.com> Subject: Re: [MASSMAIL KLMS] Re: [PATCH v10 04/18] af_vsock: implement SEQPACKET receive loop Date: Mon, 7 Jun 2021 14:28:16 +0200 [thread overview] Message-ID: <20210607122816.yas4fpfmtvlrbfku@steredhat> (raw) In-Reply-To: <95a11b19-8266-7fc0-9426-edccd4512a2d@kaspersky.com> On Mon, Jun 07, 2021 at 02:29:28PM +0300, Arseny Krasnov wrote: > >On 07.06.2021 13:48, Stefano Garzarella wrote: >> On Fri, Jun 04, 2021 at 09:00:14PM +0300, Arseny Krasnov wrote: >>> On 04.06.2021 18:06, Stefano Garzarella wrote: >>>> On Thu, May 20, 2021 at 10:16:08PM +0300, Arseny Krasnov wrote: >>>>> Add receive loop for SEQPACKET. It looks like receive loop for >>>>> STREAM, but there are differences: >>>>> 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@kaspersky.com> >>>>> --- >>>>> v9 -> v10: >>>>> 1) Use 'msg_data_left()' instead of direct access to 'msg_hdr'. >>>>> >>>>> include/net/af_vsock.h | 4 +++ >>>>> net/vmw_vsock/af_vsock.c | 72 +++++++++++++++++++++++++++++++++++++++- >>>>> 2 files changed, 75 insertions(+), 1 deletion(-) >>>>> >>>>> diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h >>>>> index b1c717286993..5175f5a52ce1 100644 >>>>> --- a/include/net/af_vsock.h >>>>> +++ b/include/net/af_vsock.h >>>>> @@ -135,6 +135,10 @@ struct vsock_transport { >>>>> bool (*stream_is_active)(struct vsock_sock *); >>>>> bool (*stream_allow)(u32 cid, u32 port); >>>>> >>>>> + /* SEQ_PACKET. */ >>>>> + ssize_t (*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 c4f6bfa1e381..aede474343d1 100644 >>>>> --- a/net/vmw_vsock/af_vsock.c >>>>> +++ b/net/vmw_vsock/af_vsock.c >>>>> @@ -1974,6 +1974,73 @@ 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; >>>>> + bool msg_ready; >>>>> + struct vsock_sock *vsk; >>>>> + ssize_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); >>>>> + msg_ready = false; >>>>> + record_len = 0; >>>>> + >>>>> + while (1) { >>>>> + ssize_t fragment_len; >>>>> + >>>>> + if (vsock_wait_data(sk, &wait, timeout, NULL, 0) <= 0) { >>>>> + /* In case of any loop break(timeout, signal >>>>> + * interrupt or shutdown), we report user that >>>>> + * nothing was copied. >>>>> + */ >>>>> + err = 0; >>>> Why we report that nothing was copied? >>>> >>>> What happen to the bytes already copied in `msg`? >>> Seems i need to return result of vsock_wait_data()... >> I'm not sure. >> >> My biggest concern is if we reach timeout or get a signal while waiting >> for the other pieces of a message. >> I believe that we should not start copying a message if we have not >> received all the fragments. Otherwise we have this problem. >> >> When we are sure that we have all the pieces, then we should copy them >> without interrupting. >> >> IIRC this was done in previous versions. > >As i remember, previous versions also returned 0, because i thought, >that for interrupted read we can copy piece of data to user's buffer, >but we must return that nothing copied or error. In this way user This can also be fine, but we should remove packet form the rx_queue only when we are sure that we delivered the entire message. > >won't read part of message, because syscall returned that there is >nothing to copy. So as i understand, it is not enough - user's buffer >must be touched only when whole message is copied? The important thing is to not remove packets from the rx_queue unless we are sure that everything went well and we are returning the entire message to the user. Stefano
WARNING: multiple messages have this Message-ID (diff)
From: Stefano Garzarella <sgarzare@redhat.com> To: Arseny Krasnov <arseny.krasnov@kaspersky.com> Cc: Andra Paraschiv <andraprs@amazon.com>, "kvm@vger.kernel.org" <kvm@vger.kernel.org>, "Michael S. Tsirkin" <mst@redhat.com>, "netdev@vger.kernel.org" <netdev@vger.kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "virtualization@lists.linux-foundation.org" <virtualization@lists.linux-foundation.org>, "oxffffaa@gmail.com" <oxffffaa@gmail.com>, Norbert Slusarek <nslusarek@gmx.net>, Stefan Hajnoczi <stefanha@redhat.com>, Colin Ian King <colin.king@canonical.com>, Jakub Kicinski <kuba@kernel.org>, "David S. Miller" <davem@davemloft.net>, Jorgen Hansen <jhansen@vmware.com> Subject: Re: [MASSMAIL KLMS] Re: [PATCH v10 04/18] af_vsock: implement SEQPACKET receive loop Date: Mon, 7 Jun 2021 14:28:16 +0200 [thread overview] Message-ID: <20210607122816.yas4fpfmtvlrbfku@steredhat> (raw) In-Reply-To: <95a11b19-8266-7fc0-9426-edccd4512a2d@kaspersky.com> On Mon, Jun 07, 2021 at 02:29:28PM +0300, Arseny Krasnov wrote: > >On 07.06.2021 13:48, Stefano Garzarella wrote: >> On Fri, Jun 04, 2021 at 09:00:14PM +0300, Arseny Krasnov wrote: >>> On 04.06.2021 18:06, Stefano Garzarella wrote: >>>> On Thu, May 20, 2021 at 10:16:08PM +0300, Arseny Krasnov wrote: >>>>> Add receive loop for SEQPACKET. It looks like receive loop for >>>>> STREAM, but there are differences: >>>>> 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@kaspersky.com> >>>>> --- >>>>> v9 -> v10: >>>>> 1) Use 'msg_data_left()' instead of direct access to 'msg_hdr'. >>>>> >>>>> include/net/af_vsock.h | 4 +++ >>>>> net/vmw_vsock/af_vsock.c | 72 +++++++++++++++++++++++++++++++++++++++- >>>>> 2 files changed, 75 insertions(+), 1 deletion(-) >>>>> >>>>> diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h >>>>> index b1c717286993..5175f5a52ce1 100644 >>>>> --- a/include/net/af_vsock.h >>>>> +++ b/include/net/af_vsock.h >>>>> @@ -135,6 +135,10 @@ struct vsock_transport { >>>>> bool (*stream_is_active)(struct vsock_sock *); >>>>> bool (*stream_allow)(u32 cid, u32 port); >>>>> >>>>> + /* SEQ_PACKET. */ >>>>> + ssize_t (*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 c4f6bfa1e381..aede474343d1 100644 >>>>> --- a/net/vmw_vsock/af_vsock.c >>>>> +++ b/net/vmw_vsock/af_vsock.c >>>>> @@ -1974,6 +1974,73 @@ 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; >>>>> + bool msg_ready; >>>>> + struct vsock_sock *vsk; >>>>> + ssize_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); >>>>> + msg_ready = false; >>>>> + record_len = 0; >>>>> + >>>>> + while (1) { >>>>> + ssize_t fragment_len; >>>>> + >>>>> + if (vsock_wait_data(sk, &wait, timeout, NULL, 0) <= 0) { >>>>> + /* In case of any loop break(timeout, signal >>>>> + * interrupt or shutdown), we report user that >>>>> + * nothing was copied. >>>>> + */ >>>>> + err = 0; >>>> Why we report that nothing was copied? >>>> >>>> What happen to the bytes already copied in `msg`? >>> Seems i need to return result of vsock_wait_data()... >> I'm not sure. >> >> My biggest concern is if we reach timeout or get a signal while waiting >> for the other pieces of a message. >> I believe that we should not start copying a message if we have not >> received all the fragments. Otherwise we have this problem. >> >> When we are sure that we have all the pieces, then we should copy them >> without interrupting. >> >> IIRC this was done in previous versions. > >As i remember, previous versions also returned 0, because i thought, >that for interrupted read we can copy piece of data to user's buffer, >but we must return that nothing copied or error. In this way user This can also be fine, but we should remove packet form the rx_queue only when we are sure that we delivered the entire message. > >won't read part of message, because syscall returned that there is >nothing to copy. So as i understand, it is not enough - user's buffer >must be touched only when whole message is copied? The important thing is to not remove packets from the rx_queue unless we are sure that everything went well and we are returning the entire message to the user. Stefano _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
next prev parent reply other threads:[~2021-06-07 12:28 UTC|newest] Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-20 19:13 [PATCH v10 00/18] virtio/vsock: introduce SOCK_SEQPACKET support Arseny Krasnov 2021-05-20 19:14 ` [PATCH v10 01/18] af_vsock: update functions for connectible socket Arseny Krasnov 2021-05-20 19:15 ` [PATCH v10 02/18] af_vsock: separate wait data loop Arseny Krasnov 2021-05-20 19:15 ` [PATCH v10 03/18] af_vsock: separate receive " Arseny Krasnov 2021-05-20 19:16 ` [PATCH v10 04/18] af_vsock: implement SEQPACKET receive loop Arseny Krasnov 2021-05-25 14:08 ` Stefano Garzarella 2021-05-25 14:08 ` Stefano Garzarella 2021-06-04 15:06 ` Stefano Garzarella 2021-06-04 15:06 ` Stefano Garzarella 2021-06-04 18:00 ` [MASSMAIL KLMS] " Arseny Krasnov 2021-06-07 10:48 ` Stefano Garzarella 2021-06-07 10:48 ` Stefano Garzarella 2021-06-07 11:29 ` Arseny Krasnov 2021-06-07 12:28 ` Stefano Garzarella [this message] 2021-06-07 12:28 ` Stefano Garzarella 2021-05-20 19:16 ` [PATCH v10 05/18] af_vsock: implement send logic for SEQPACKET Arseny Krasnov 2021-05-20 19:16 ` [PATCH v10 06/18] af_vsock: rest of SEQPACKET support Arseny Krasnov 2021-05-25 14:17 ` Stefano Garzarella 2021-05-25 14:17 ` Stefano Garzarella 2021-05-20 19:16 ` [PATCH v10 07/18] af_vsock: update comments for stream sockets Arseny Krasnov 2021-05-20 19:17 ` [PATCH v10 08/18] virtio/vsock: set packet's type in virtio_transport_send_pkt_info() Arseny Krasnov 2021-05-20 19:17 ` [PATCH v10 09/18] virtio/vsock: simplify credit update function API Arseny Krasnov 2021-05-20 19:17 ` [PATCH v10 10/18] virtio/vsock: defines and constants for SEQPACKET Arseny Krasnov 2021-05-20 19:17 ` [PATCH v10 11/18] virtio/vsock: dequeue callback for SOCK_SEQPACKET Arseny Krasnov 2021-06-03 14:45 ` Stefano Garzarella 2021-06-03 14:45 ` Stefano Garzarella 2021-06-04 13:12 ` Arseny Krasnov 2021-06-04 15:03 ` Stefano Garzarella 2021-06-04 15:03 ` Stefano Garzarella 2021-06-04 18:03 ` Arseny Krasnov 2021-06-07 11:04 ` Stefano Garzarella 2021-06-07 11:04 ` Stefano Garzarella 2021-06-07 13:18 ` Arseny Krasnov 2021-06-08 8:23 ` Stefano Garzarella 2021-06-08 8:23 ` Stefano Garzarella 2021-06-08 9:40 ` Arseny Krasnov 2021-06-08 10:19 ` Stefano Garzarella 2021-06-08 10:19 ` Stefano Garzarella 2021-06-08 10:24 ` Arseny Krasnov 2021-06-08 10:39 ` Stefano Garzarella 2021-06-08 10:39 ` Stefano Garzarella 2021-05-20 19:18 ` [PATCH v10 12/18] virtio/vsock: add SEQPACKET receive logic Arseny Krasnov 2021-06-03 14:56 ` Stefano Garzarella 2021-06-03 14:56 ` Stefano Garzarella 2021-05-20 19:18 ` [PATCH v10 13/18] virtio/vsock: rest of SOCK_SEQPACKET support Arseny Krasnov 2021-06-03 15:14 ` Stefano Garzarella 2021-06-03 15:14 ` Stefano Garzarella 2021-05-20 19:18 ` [PATCH v10 14/18] virtio/vsock: enable SEQPACKET for transport Arseny Krasnov 2021-06-03 15:22 ` Stefano Garzarella 2021-06-03 15:22 ` Stefano Garzarella 2021-05-20 19:19 ` [PATCH v10 15/18] vhost/vsock: support " Arseny Krasnov 2021-06-03 15:34 ` Stefano Garzarella 2021-06-03 15:34 ` Stefano Garzarella 2021-06-04 13:13 ` Arseny Krasnov 2021-05-20 19:19 ` [PATCH v10 16/18] vsock/loopback: enable " Arseny Krasnov 2021-05-20 19:19 ` [PATCH v10 17/18] vsock_test: add SOCK_SEQPACKET tests Arseny Krasnov 2021-06-03 15:38 ` Stefano Garzarella 2021-06-03 15:38 ` Stefano Garzarella 2021-05-20 19:20 ` [PATCH v10 18/18] virtio/vsock: update trace event for SEQPACKET Arseny Krasnov 2021-06-03 15:40 ` Stefano Garzarella 2021-06-03 15:40 ` Stefano Garzarella 2021-05-21 7:55 ` [PATCH v10 00/18] virtio/vsock: introduce SOCK_SEQPACKET support Stefano Garzarella 2021-05-21 7:55 ` Stefano Garzarella 2021-05-23 12:14 ` Arseny Krasnov 2021-05-25 8:22 ` Arseny Krasnov 2021-05-25 14:52 ` Stefano Garzarella 2021-05-25 14:52 ` Stefano Garzarella 2021-05-26 12:16 ` Arseny Krasnov
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