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Message-ID: <20230725172912.1659970-3-AVKrasnov@sberdevices.ru>
Date: Tue, 25 Jul 2023 20:29:10 +0300
From: Arseniy Krasnov <AVKrasnov@...rdevices.ru>
To: Stefan Hajnoczi <stefanha@...hat.com>,
Stefano Garzarella <sgarzare@...hat.com>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
"Michael S. Tsirkin" <mst@...hat.com>,
Jason Wang <jasowang@...hat.com>,
Bobby Eshleman <bobby.eshleman@...edance.com>
CC: <kvm@...r.kernel.org>, <virtualization@...ts.linux-foundation.org>,
<netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<kernel@...rdevices.ru>, <oxffffaa@...il.com>,
<avkrasnov@...rdevices.ru>,
Arseniy Krasnov <AVKrasnov@...rdevices.ru>
Subject: [PATCH net-next v3 2/4] virtio/vsock: support MSG_PEEK for SOCK_SEQPACKET
This adds support of MSG_PEEK flag for SOCK_SEQPACKET type of socket.
Difference with SOCK_STREAM is that this callback returns either length
of the message or error.
Signed-off-by: Arseniy Krasnov <AVKrasnov@...rdevices.ru>
Reviewed-by: Stefano Garzarella <sgarzare@...hat.com>
---
net/vmw_vsock/virtio_transport_common.c | 63 +++++++++++++++++++++++--
1 file changed, 60 insertions(+), 3 deletions(-)
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 2ee40574c339..352d042b130b 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -460,6 +460,63 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
return err;
}
+static ssize_t
+virtio_transport_seqpacket_do_peek(struct vsock_sock *vsk,
+ struct msghdr *msg)
+{
+ struct virtio_vsock_sock *vvs = vsk->trans;
+ struct sk_buff *skb;
+ size_t total, len;
+
+ spin_lock_bh(&vvs->rx_lock);
+
+ if (!vvs->msg_count) {
+ spin_unlock_bh(&vvs->rx_lock);
+ return 0;
+ }
+
+ total = 0;
+ len = msg_data_left(msg);
+
+ skb_queue_walk(&vvs->rx_queue, skb) {
+ struct virtio_vsock_hdr *hdr;
+
+ if (total < len) {
+ size_t bytes;
+ int err;
+
+ bytes = len - total;
+ if (bytes > skb->len)
+ bytes = skb->len;
+
+ spin_unlock_bh(&vvs->rx_lock);
+
+ /* sk_lock is held by caller so no one else can dequeue.
+ * Unlock rx_lock since memcpy_to_msg() may sleep.
+ */
+ err = memcpy_to_msg(msg, skb->data, bytes);
+ if (err)
+ return err;
+
+ spin_lock_bh(&vvs->rx_lock);
+ }
+
+ total += skb->len;
+ hdr = virtio_vsock_hdr(skb);
+
+ if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOM) {
+ if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOR)
+ msg->msg_flags |= MSG_EOR;
+
+ break;
+ }
+ }
+
+ spin_unlock_bh(&vvs->rx_lock);
+
+ return total;
+}
+
static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
struct msghdr *msg,
int flags)
@@ -554,9 +611,9 @@ virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
int flags)
{
if (flags & MSG_PEEK)
- return -EOPNOTSUPP;
-
- return virtio_transport_seqpacket_do_dequeue(vsk, msg, flags);
+ return virtio_transport_seqpacket_do_peek(vsk, msg);
+ else
+ return virtio_transport_seqpacket_do_dequeue(vsk, msg, flags);
}
EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_dequeue);
--
2.25.1
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