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>, Norbert Slusarek <nslusarek@gmx.net>, Colin Ian King <colin.king@canonical.com>, Andra Paraschiv <andraprs@amazon.com>, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, oxffffaa@gmail.com Subject: Re: [PATCH v10 11/18] virtio/vsock: dequeue callback for SOCK_SEQPACKET Date: Thu, 3 Jun 2021 16:45:13 +0200 [thread overview] Message-ID: <20210603144513.ryjzauq7abnjogu3@steredhat> (raw) In-Reply-To: <20210520191801.1272027-1-arseny.krasnov@kaspersky.com> On Thu, May 20, 2021 at 10:17:58PM +0300, Arseny Krasnov wrote: >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. > >Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com> >--- > v9 -> v10: > 1) Number of dequeued bytes incremented even in case when > user's buffer is full. > 2) Use 'msg_data_left()' instead of direct access to 'msg_hdr'. > 3) Rename variable 'err' to 'dequeued_len', in case of error > it has negative value. > > include/linux/virtio_vsock.h | 5 ++ > net/vmw_vsock/virtio_transport_common.c | 65 +++++++++++++++++++++++++ > 2 files changed, 70 insertions(+) > >diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h >index dc636b727179..02acf6e9ae04 100644 >--- a/include/linux/virtio_vsock.h >+++ b/include/linux/virtio_vsock.h >@@ -80,6 +80,11 @@ virtio_transport_dgram_dequeue(struct vsock_sock *vsk, > struct msghdr *msg, > size_t len, int flags); > >+ssize_t >+virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk, >+ struct msghdr *msg, >+ int flags, >+ bool *msg_ready); > 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_common.c b/net/vmw_vsock/virtio_transport_common.c >index ad0d34d41444..61349b2ea7fe 100644 >--- a/net/vmw_vsock/virtio_transport_common.c >+++ b/net/vmw_vsock/virtio_transport_common.c >@@ -393,6 +393,59 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk, > return err; > } > >+static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk, >+ struct msghdr *msg, >+ int flags, >+ bool *msg_ready) >+{ >+ struct virtio_vsock_sock *vvs = vsk->trans; >+ struct virtio_vsock_pkt *pkt; >+ int dequeued_len = 0; >+ size_t user_buf_len = msg_data_left(msg); >+ >+ *msg_ready = false; >+ spin_lock_bh(&vvs->rx_lock); >+ >+ while (!*msg_ready && !list_empty(&vvs->rx_queue) && dequeued_len >= 0) { I' >+ size_t bytes_to_copy; >+ size_t pkt_len; >+ >+ pkt = list_first_entry(&vvs->rx_queue, struct virtio_vsock_pkt, list); >+ pkt_len = (size_t)le32_to_cpu(pkt->hdr.len); >+ bytes_to_copy = min(user_buf_len, pkt_len); >+ >+ if (bytes_to_copy) { >+ /* 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)) >+ dequeued_len = -EINVAL; I think here is better to return the error returned by memcpy_to_msg(), as we do in the other place where we use memcpy_to_msg(). I mean something like this: err = memcpy_to_msgmsg, pkt->buf, bytes_to_copy); if (err) dequeued_len = err; >+ else >+ user_buf_len -= bytes_to_copy; >+ >+ spin_lock_bh(&vvs->rx_lock); >+ } >+ Maybe here we can simply break the cycle if we have an error: if (dequeued_len < 0) break; Or we can refactor a bit, simplifying the while() condition and also the code in this way (not tested): while (!*msg_ready && !list_empty(&vvs->rx_queue)) { ... if (bytes_to_copy) { int err; /* ... */ spin_unlock_bh(&vvs->rx_lock); err = memcpy_to_msgmsg, pkt->buf, bytes_to_copy); if (err) { dequeued_len = err; goto out; } spin_lock_bh(&vvs->rx_lock); user_buf_len -= bytes_to_copy; } dequeued_len += pkt_len; if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOR) *msg_ready = true; virtio_transport_dec_rx_pkt(vvs, pkt); list_del(&pkt->list); virtio_transport_free_pkt(pkt); } out: spin_unlock_bh(&vvs->rx_lock); virtio_transport_send_credit_update(vsk); return dequeued_len; }
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, "Michael S. Tsirkin" <mst@redhat.com>, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, 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: [PATCH v10 11/18] virtio/vsock: dequeue callback for SOCK_SEQPACKET Date: Thu, 3 Jun 2021 16:45:13 +0200 [thread overview] Message-ID: <20210603144513.ryjzauq7abnjogu3@steredhat> (raw) In-Reply-To: <20210520191801.1272027-1-arseny.krasnov@kaspersky.com> On Thu, May 20, 2021 at 10:17:58PM +0300, Arseny Krasnov wrote: >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. > >Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com> >--- > v9 -> v10: > 1) Number of dequeued bytes incremented even in case when > user's buffer is full. > 2) Use 'msg_data_left()' instead of direct access to 'msg_hdr'. > 3) Rename variable 'err' to 'dequeued_len', in case of error > it has negative value. > > include/linux/virtio_vsock.h | 5 ++ > net/vmw_vsock/virtio_transport_common.c | 65 +++++++++++++++++++++++++ > 2 files changed, 70 insertions(+) > >diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h >index dc636b727179..02acf6e9ae04 100644 >--- a/include/linux/virtio_vsock.h >+++ b/include/linux/virtio_vsock.h >@@ -80,6 +80,11 @@ virtio_transport_dgram_dequeue(struct vsock_sock *vsk, > struct msghdr *msg, > size_t len, int flags); > >+ssize_t >+virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk, >+ struct msghdr *msg, >+ int flags, >+ bool *msg_ready); > 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_common.c b/net/vmw_vsock/virtio_transport_common.c >index ad0d34d41444..61349b2ea7fe 100644 >--- a/net/vmw_vsock/virtio_transport_common.c >+++ b/net/vmw_vsock/virtio_transport_common.c >@@ -393,6 +393,59 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk, > return err; > } > >+static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk, >+ struct msghdr *msg, >+ int flags, >+ bool *msg_ready) >+{ >+ struct virtio_vsock_sock *vvs = vsk->trans; >+ struct virtio_vsock_pkt *pkt; >+ int dequeued_len = 0; >+ size_t user_buf_len = msg_data_left(msg); >+ >+ *msg_ready = false; >+ spin_lock_bh(&vvs->rx_lock); >+ >+ while (!*msg_ready && !list_empty(&vvs->rx_queue) && dequeued_len >= 0) { I' >+ size_t bytes_to_copy; >+ size_t pkt_len; >+ >+ pkt = list_first_entry(&vvs->rx_queue, struct virtio_vsock_pkt, list); >+ pkt_len = (size_t)le32_to_cpu(pkt->hdr.len); >+ bytes_to_copy = min(user_buf_len, pkt_len); >+ >+ if (bytes_to_copy) { >+ /* 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)) >+ dequeued_len = -EINVAL; I think here is better to return the error returned by memcpy_to_msg(), as we do in the other place where we use memcpy_to_msg(). I mean something like this: err = memcpy_to_msgmsg, pkt->buf, bytes_to_copy); if (err) dequeued_len = err; >+ else >+ user_buf_len -= bytes_to_copy; >+ >+ spin_lock_bh(&vvs->rx_lock); >+ } >+ Maybe here we can simply break the cycle if we have an error: if (dequeued_len < 0) break; Or we can refactor a bit, simplifying the while() condition and also the code in this way (not tested): while (!*msg_ready && !list_empty(&vvs->rx_queue)) { ... if (bytes_to_copy) { int err; /* ... */ spin_unlock_bh(&vvs->rx_lock); err = memcpy_to_msgmsg, pkt->buf, bytes_to_copy); if (err) { dequeued_len = err; goto out; } spin_lock_bh(&vvs->rx_lock); user_buf_len -= bytes_to_copy; } dequeued_len += pkt_len; if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOR) *msg_ready = true; virtio_transport_dec_rx_pkt(vvs, pkt); list_del(&pkt->list); virtio_transport_free_pkt(pkt); } out: spin_unlock_bh(&vvs->rx_lock); virtio_transport_send_credit_update(vsk); return dequeued_len; } _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
next prev parent reply other threads:[~2021-06-03 14:47 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 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 [this message] 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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