[PATCH v2] vsock/virtio: add support for MSG_PEEK
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STALE2578d
From: Matias Ezequiel Vara Larsen <hidden>
Date: 2019-09-27 16:45:12
Also in:
kvm, lkml
Subsystem:
networking [general], the rest, virtio and vhost vsock driver, virtio core, vm sockets (af_vsock) · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Stefan Hajnoczi, Stefano Garzarella, "Michael S. Tsirkin", Jason Wang, Eugenio Pérez
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 <redacted> --- net/vmw_vsock/virtio_transport_common.c | 55 +++++++++++++++++++++++++++++++-- 1 file changed, 52 insertions(+), 3 deletions(-)
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 94cc0fa..cf15751 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c@@ -264,6 +264,55 @@ static int virtio_transport_send_credit_update(struct vsock_sock *vsk, } 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, size_t len)
@@ -330,9 +379,9 @@ 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);
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2.7.4