@@ -451,6 +451,8 @@ static struct virtio_transport vhost_transport = {
.notify_buffer_size = virtio_transport_notify_buffer_size,
.read_skb = virtio_transport_read_skb,
+
+ .set_rcvlowat = virtio_transport_set_rcvlowat
},
.send_pkt = vhost_transport_send_pkt,
@@ -256,4 +256,5 @@ void virtio_transport_put_credit(struct virtio_vsock_sock *vvs, u32 credit);
void virtio_transport_deliver_tap_pkt(struct sk_buff *skb);
int virtio_transport_purge_skbs(void *vsk, struct sk_buff_head *list);
int virtio_transport_read_skb(struct vsock_sock *vsk, skb_read_actor_t read_actor);
+int virtio_transport_set_rcvlowat(struct vsock_sock *vsk, int val);
#endif /* _LINUX_VIRTIO_VSOCK_H */
@@ -539,6 +539,8 @@ static struct virtio_transport virtio_transport = {
.notify_buffer_size = virtio_transport_notify_buffer_size,
.read_skb = virtio_transport_read_skb,
+
+ .set_rcvlowat = virtio_transport_set_rcvlowat
},
.send_pkt = virtio_transport_send_pkt,
@@ -1684,6 +1684,34 @@ int virtio_transport_read_skb(struct vsock_sock *vsk, skb_read_actor_t recv_acto
}
EXPORT_SYMBOL_GPL(virtio_transport_read_skb);
+int virtio_transport_set_rcvlowat(struct vsock_sock *vsk, int val)
+{
+ struct virtio_vsock_sock *vvs = vsk->trans;
+ bool send_update;
+
+ spin_lock_bh(&vvs->rx_lock);
+
+ /* If number of available bytes is less than new
+ * SO_RCVLOWAT value, kick sender to send more
+ * data, because sender may sleep in its 'send()'
+ * syscall waiting for enough space at our side.
+ */
+ send_update = vvs->rx_bytes < val;
+
+ spin_unlock_bh(&vvs->rx_lock);
+
+ if (send_update) {
+ int err;
+
+ err = virtio_transport_send_credit_update(vsk);
+ if (err < 0)
+ return err;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_set_rcvlowat);
+
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Asias He");
MODULE_DESCRIPTION("common code for virtio vsock");
@@ -98,6 +98,8 @@ static struct virtio_transport loopback_transport = {
.notify_buffer_size = virtio_transport_notify_buffer_size,
.read_skb = virtio_transport_read_skb,
+
+ .set_rcvlowat = virtio_transport_set_rcvlowat
},
.send_pkt = vsock_loopback_send_pkt,
Send credit update message when SO_RCVLOWAT is updated and it is bigger than number of bytes in rx queue. It is needed, because 'poll()' will wait until number of bytes in rx queue will be not smaller than SO_RCVLOWAT, so kick sender to send more data. Otherwise mutual hungup for tx/rx is possible: sender waits for free space and receiver is waiting data in 'poll()'. Signed-off-by: Arseniy Krasnov <avkrasnov@salutedevices.com> --- Changelog: v1 -> v2: * Update commit message by removing 'This patch adds XXX' manner. * Do not initialize 'send_update' variable - set it directly during first usage. drivers/vhost/vsock.c | 2 ++ include/linux/virtio_vsock.h | 1 + net/vmw_vsock/virtio_transport.c | 2 ++ net/vmw_vsock/virtio_transport_common.c | 28 +++++++++++++++++++++++++ net/vmw_vsock/vsock_loopback.c | 2 ++ 5 files changed, 35 insertions(+)