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Date:   Mon, 15 Mar 2021 12:02:09 +0100
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>,
        Norbert Slusarek <nslusarek@gmx.net>,
        Andra Paraschiv <andraprs@amazon.com>, kvm@vger.kernel.org,
        virtualization@lists.linux-foundation.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, stsp2@yandex.ru, oxffffaa@gmail.com
Subject: Re: [RFC PATCH v6 11/22] virtio/vsock: dequeue callback for
 SOCK_SEQPACKET
Message-ID: <20210315110209.xuaq5q3a2zp4u3g5@steredhat>
References: <20210307175722.3464068-1-arseny.krasnov@kaspersky.com>
 <20210307180204.3465806-1-arseny.krasnov@kaspersky.com>
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In-Reply-To: <20210307180204.3465806-1-arseny.krasnov@kaspersky.com>
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On Sun, Mar 07, 2021 at 09:02:01PM +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            |  13 +++
> include/uapi/linux/virtio_vsock.h       |  16 ++++
> net/vmw_vsock/virtio_transport_common.c | 116 ++++++++++++++++++++++++
> 3 files changed, 145 insertions(+)
>
>diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>index dc636b727179..466a5832d2f5 100644
>--- a/include/linux/virtio_vsock.h
>+++ b/include/linux/virtio_vsock.h
>@@ -18,6 +18,12 @@ enum {
> 	VSOCK_VQ_MAX    = 3,
> };
>
>+struct virtio_vsock_seqpack_state {
>+	u32 user_read_seq_len;
>+	u32 user_read_copied;
>+	u32 curr_rx_msg_id;
>+};
>+
> /* Per-socket state (accessed via vsk->trans) */
> struct virtio_vsock_sock {
> 	struct vsock_sock *vsk;
>@@ -36,6 +42,8 @@ struct virtio_vsock_sock {
> 	u32 rx_bytes;
> 	u32 buf_alloc;
> 	struct list_head rx_queue;
>+
>+	struct virtio_vsock_seqpack_state seqpacket_state;

Following 'virtio_vsock_seq_hdr', maybe we can shorten in:

         struct virtio_vsock_seq_state seq_state;

The rest LGTM.