Re: [PATCH net-next RFC] net: x25: Queue received packets in the drivers instead of per-CPU queues

[Martin Schiller]

On 2021-03-05 06:43, Xie He wrote:
> X.25 Layer 3 (the Packet Layer) expects layer 2 to provide a reliable
> datalink service such that no packets are reordered or dropped. And
> X.25 Layer 2 (the LAPB layer) is indeed designed to provide such 
> service.
>
> However, this reliability is not preserved when a driver calls 
> "netif_rx"
> to deliver the received packets to layer 3, because "netif_rx" will put
> the packets into per-CPU queues before they are delivered to layer 3.
> If there are multiple CPUs, the order of the packets may not be 
> preserved.
> The per-CPU queues may also drop packets if there are too many.
>
> Therefore, we should not call "netif_rx" to let it queue the packets.
> Instead, we should use our own queue that won't reorder or drop 
> packets.
>
> This patch changes all X.25 drivers to use their own queues instead of
> calling "netif_rx". The patch also documents this requirement in the
> "x25-iface" documentation.

I've tested the hdlc_x25 driver.
Looks good to me.

Acked-by: Martin Schiller <ms@xxxxxxxxxx>