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vsock/virtio: add support for MSG_PEEK

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This patch adds support for MSG_PEEK. In such a case, packets are not
removed from the rx_queue and credit updates are not sent.

Signed-off-by: Matias Ezequiel Vara Larsen <matiasevara@gmail.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Tested-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Matias Ezequiel Vara Larsen 2019-09-30 18:25:23 +00:00 committed by David S. Miller
parent 678799194a
commit a786ab36ae
1 changed files with 52 additions and 3 deletions
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55
net/vmw_vsock/virtio_transport_common.c
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@ -263,6 +263,55 @@ static int virtio_transport_send_credit_update(struct vsock_sock *vsk,
return virtio_transport_send_pkt_info(vsk, &info);
}
static ssize_t
virtio_transport_stream_do_peek(struct vsock_sock *vsk,
struct msghdr *msg,
size_t len)
{
struct virtio_vsock_sock *vvs = vsk->trans;
struct virtio_vsock_pkt *pkt;
size_t bytes, total = 0, off;
int err = -EFAULT;
spin_lock_bh(&vvs->rx_lock);
list_for_each_entry(pkt, &vvs->rx_queue, list) {
off = pkt->off;
if (total == len)
break;
while (total < len && off < pkt->len) {
bytes = len - total;
if (bytes > pkt->len - off)
bytes = pkt->len - off;
/* 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);
err = memcpy_to_msg(msg, pkt->buf + off, bytes);
if (err)
goto out;
spin_lock_bh(&vvs->rx_lock);
total += bytes;
off += bytes;
}
}
spin_unlock_bh(&vvs->rx_lock);
return total;
out:
if (total)
err = total;
return err;
}
static ssize_t
virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
struct msghdr *msg,
@ -335,9 +384,9 @@ virtio_transport_stream_dequeue(struct vsock_sock *vsk,
size_t len, int flags)
{
if (flags & MSG_PEEK)
return -EOPNOTSUPP;
return virtio_transport_stream_do_dequeue(vsk, msg, len);
return virtio_transport_stream_do_peek(vsk, msg, len);
else
return virtio_transport_stream_do_dequeue(vsk, msg, len);
}
EXPORT_SYMBOL_GPL(virtio_transport_stream_dequeue);