From: David Miller <davem@davemloft.net>
To: xie.he.0141@gmail.com
Cc: ms@dev.tdt.de, kuba@kernel.org, corbet@lwn.net, khc@pm.waw.pl,
linux-x25@vger.kernel.org, netdev@vger.kernel.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next v5] net: x25: Queue received packets in the drivers instead of per-CPU queues
Date: Tue, 06 Apr 2021 16:14:31 -0700 (PDT) [thread overview]
Message-ID: <20210406.161431.1568805748449868568.davem@davemloft.net> (raw)
In-Reply-To: <20210402093000.72965-1-xie.he.0141@gmail.com>
From: Xie He <xie.he.0141@gmail.com>
Date: Fri, 2 Apr 2021 02:30:00 -0700
> 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.
>
> Cc: Martin Schiller <ms@dev.tdt.de>
> Signed-off-by: Xie He <xie.he.0141@gmail.com>
This no longe applies to net-next, please respin.
Thank you.
next prev parent reply other threads:[~2021-04-06 23:14 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-02 9:30 [PATCH net-next v5] net: x25: Queue received packets in the drivers instead of per-CPU queues Xie He
2021-04-05 19:34 ` Xie He
2021-04-06 6:17 ` Martin Schiller
2021-04-06 8:49 ` Xie He
2021-04-06 23:14 ` David Miller [this message]
2021-04-06 23:55 ` Xie He
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