Re: [PATCH net-next v5 2/5] vsock/virtio: factor RX skb metadata budget check

[Stefano Garzarella <sgarzare@redhat.com>]

On Tue, Nov 03, 2026 at 12:11:31PM +0800, Jia Jia wrote:
>Extract the skb metadata budget check from virtio_transport_inc_rx_pkt()
>into virtio_transport_rx_buf_full().
>
>The helper retains the existing condition and will be reused by a
>following RX batching change.
>
>Signed-off-by: Jia Jia <physicalmtea@gmail.com>
>---
> net/vmw_vsock/virtio_transport_common.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
>diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>index 43325d7aebbb1..2a9cfed085515 100644
>--- a/net/vmw_vsock/virtio_transport_common.c
>+++ b/net/vmw_vsock/virtio_transport_common.c
>@@ -576,11 +576,17 @@ virtio_transport_collapse_rx_queue(struct virtio_vsock_sock *vvs,
> 	skb_queue_splice(&new_queue, &vvs->rx_queue);
> }
>
>-static bool virtio_transport_inc_rx_pkt(struct virtio_vsock_sock *vvs,
>-					u32 len)
>+static bool
>+virtio_transport_rx_buf_full(struct virtio_vsock_sock *vvs)
> {
> 	u64 skb_overhead = (skb_queue_len(&vvs->rx_queue) + 1) * SKB_TRUESIZE(0);
>
>+	return skb_overhead > vvs->buf_alloc;
>+}

As I pointed out in patch 3, I'm not sure we need this.
After we introduced the collapse, SOCK_STREAM should collapse rx_queue 
before hitting this, so not sure we really need this function.

Thanks,
Stefano

>+
>+static bool virtio_transport_inc_rx_pkt(struct virtio_vsock_sock *vvs,
>+					u32 len)
>+{
> 	/* Allow at most buf_alloc * 2 total budget (payload + overhead),
> 	 * similar to how SO_RCVBUF is doubled to reserve space for sk_buff
> 	 * metadata. Check payload against buf_alloc to be sure the other
>@@ -588,7 +594,7 @@ static bool virtio_transport_inc_rx_pkt(struct virtio_vsock_sock *vvs,
> 	 * queue growth.
> 	 */
> 	if ((u64)vvs->buf_used + len > vvs->buf_alloc ||
>-	    skb_overhead > vvs->buf_alloc)
>+	    virtio_transport_rx_buf_full(vvs))
> 		return false;
>
> 	vvs->rx_bytes += len;
>-- 
>2.53.0
>