Re: [PATCH net-next v3 7/7] mptcp: implemented OoO queue pruning

[Eric Dumazet]

On Fri, Aug 7, 2026 at 3:50 PM Matthieu Baerts (NGI0)
<matttbe@xxxxxxxxxx> wrote:
>
> From: Paolo Abeni <pabeni@xxxxxxxxxx>
>
> When moving incoming skbs in the msk receive queue and the latter
> is above limits, prune it as needed quite alike what TCP is doing
> at the subflow level. The main difference relies in the stop condition:
> since MPTCP does not perform collapsing, it's better off dropping the
> bare minimum to fit the (newer) incoming packet.
>
> Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
> Tested-by: Gang Yan <yangang@xxxxxxxxxx>
> Reviewed-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
> ---
> v2:
>  - Uniform the new counter with the other OFO ones.
> v3:
>  - prune only for new data
>  - reorganize the code to follow more closely TCP
> ---

...

> +
> +/* The stack can't drop packets for fallback socket at the msk level, or the
> + * stream will break.
> + */
> +static bool mptcp_can_ingest(const struct sock *sk)
> +{
> +       return unlikely(sk_rmem_alloc_get(sk) <= READ_ONCE(sk->sk_rcvbuf)) ||
> +                       __mptcp_check_fallback(mptcp_sk(sk));
> +}
> +

This unlikely() seems inverted.