[PATCH v2 2/4] vhost-vsock: add pkt cancel capability

[Peng Tao]

To allow canceling all packets of a connection.

Signed-off-by: Peng Tao <bergw...@gmail.com>
---
 drivers/vhost/vsock.c        | 41 +++++++++++++++++++++++++++++++++++++++++
 include/linux/virtio_vsock.h |  3 +++
 2 files changed, 44 insertions(+)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index a504e2e0..d01e4a4 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -218,6 +218,46 @@ vhost_transport_send_pkt(struct virtio_vsock_pkt *pkt)
        return len;
 }
 
+static int
+vhost_transport_cancel_pkt(struct vsock_sock *vsk)
+{
+       struct vhost_vsock *vsock;
+       struct virtio_vsock_pkt *pkt, *n;
+       int cnt = 0;
+       LIST_HEAD(freeme);
+
+       /* Find the vhost_vsock according to guest context id  */
+       vsock = vhost_vsock_get(vsk->remote_addr.svm_cid);
+       if (!vsock)
+               return -ENODEV;
+
+       spin_lock_bh(&vsock->send_pkt_list_lock);
+       list_for_each_entry_safe(pkt, n, &vsock->send_pkt_list, list) {
+               if (pkt->vsk != vsk)
+                       continue;
+               list_move(&pkt->list, &freeme);
+       }
+       spin_unlock_bh(&vsock->send_pkt_list_lock);
+
+       list_for_each_entry_safe(pkt, n, &freeme, list) {
+               if (pkt->reply)
+                       cnt++;
+               list_del(&pkt->list);
+               virtio_transport_free_pkt(pkt);
+       }
+
+       if (cnt) {
+               struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX];
+               int new_cnt;
+
+               new_cnt = atomic_sub_return(cnt, &vsock->queued_replies);
+               if (new_cnt + cnt >= tx_vq->num && new_cnt < tx_vq->num)
+                       vhost_poll_queue(&tx_vq->poll);
+       }
+
+       return 0;
+}
+
 static struct virtio_vsock_pkt *
 vhost_vsock_alloc_pkt(struct vhost_virtqueue *vq,
                      unsigned int out, unsigned int in)
@@ -698,6 +738,7 @@ static struct virtio_transport vhost_transport = {
        },
 
        .send_pkt = vhost_transport_send_pkt,
+       .cancel_pkt = vhost_transport_cancel_pkt,
 };
 
 static int __init vhost_vsock_init(void)
diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index 6dd3242..b92e88d 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -72,6 +72,9 @@ struct virtio_transport {
 
        /* Takes ownership of the packet */
        int (*send_pkt)(struct virtio_vsock_pkt *pkt);
+
+       /* Cancel packets belonging the same vsock */
+       int (*cancel_pkt)(struct vsock_sock *vsk);
 };
 
 ssize_t
-- 
2.7.4