On Wed, Oct 09, 2024 at 11:20:51PM GMT, Michal Luczaj wrote:
Make sure virtio_transport_inc_rx_pkt() and virtio_transport_dec_rx_pkt()
calls are balanced (i.e. virtio_vsock_sock::rx_bytes doesn't lie) after
vsock_transport::read_skb().
Failing to update rx_bytes after packet is dequeued leads to a warning on
SOCK_STREAM recv():
[ 233.396654] rx_queue is empty, but rx_bytes is non-zero
[ 233.396702] WARNING: CPU: 11 PID: 40601 at net/vmw_vsock/virtio_transport_common.c:589
Fixes: 634f1a7110b4 ("vsock: support sockmap")
Signed-off-by: Michal Luczaj <mhal@xxxxxxx>
---
net/vmw_vsock/virtio_transport_common.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
The modification looks good to me, but now that I'm looking at it
better, I don't understand why we don't also call
virtio_transport_send_credit_update().
This is to inform the peer that we've freed up space and it has more
credit.
@Bobby do you remember?
I think we should try to unify the receiving path used through BPF or
not (not for this series of course).
Thanks,
Stefano
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 884ee128851e5ce8b01c78fcb95a408986f62936..ed1c1bed5700e5988a233cea146cf9fac95426e0 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -1707,6 +1707,7 @@ int virtio_transport_read_skb(struct vsock_sock *vsk, skb_read_actor_t recv_acto
{
struct virtio_vsock_sock *vvs = vsk->trans;
struct sock *sk = sk_vsock(vsk);
+ struct virtio_vsock_hdr *hdr;
struct sk_buff *skb;
int off = 0;
int err;
@@ -1716,10 +1717,14 @@ int virtio_transport_read_skb(struct vsock_sock *vsk, skb_read_actor_t recv_acto
* works for types other than dgrams.
*/
skb = __skb_recv_datagram(sk, &vvs->rx_queue, MSG_DONTWAIT, &off, &err);
- spin_unlock_bh(&vvs->rx_lock);
-
- if (!skb)
+ if (!skb) {
+ spin_unlock_bh(&vvs->rx_lock);
return err;
+ }
+
+ hdr = virtio_vsock_hdr(skb);
+ virtio_transport_dec_rx_pkt(vvs, le32_to_cpu(hdr->len));
+ spin_unlock_bh(&vvs->rx_lock);
return recv_actor(sk, skb);
}
--
2.46.2
