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From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: Xie He <xie.he.0141@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Network Development <netdev@vger.kernel.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Linux X25 <linux-x25@vger.kernel.org>,
	Martin Schiller <ms@dev.tdt.de>
Subject: Re: [PATCH net] drivers/net/wan/lapbether: Added needed_tailroom
Date: Mon, 10 Aug 2020 09:31:43 +0200	[thread overview]
Message-ID: <CA+FuTSdBNn218kuswND5OE4vZ4mxz3_hTDkcRmZn2Z9-gaYQZg@mail.gmail.com> (raw)
In-Reply-To: <CAJht_EM9q9u34LMAeYsYe5voZ54s3Z7OzxtvSomcF9a9wRvuCQ@mail.gmail.com>

On Sun, Aug 9, 2020 at 7:12 PM Xie He <xie.he.0141@gmail.com> wrote:
>
> On Sun, Aug 9, 2020 at 1:48 AM Willem de Bruijn
> <willemdebruijn.kernel@gmail.com> wrote:
> >
> > Does this solve an actual observed bug?
> >
> > In many ways lapbeth is similar to tunnel devices. This is not common.
>
> Thank you for your comment!
>
> This doesn't solve a bug observed by me. But I think this should be
> necessary considering the logic of the code.
>
> Using "grep", I found that there were indeed Ethernet drivers that set
> needed_tailroom. I found it was set in these files:
>     drivers/net/ethernet/sun/sunvnet.c
>     drivers/net/ethernet/sun/ldmvsw.c
> Setting needed_tailroom may be necessary for this driver to run those
> Ethernet devices.

What happens when a tunnel device passes a packet to these devices?
That will also not have allocated the extra tailroom. Does that cause
a bug?

  reply	other threads:[~2020-08-10  7:32 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-08 17:52 Xie He
2020-08-09  8:48 ` Willem de Bruijn
2020-08-09 17:11   ` Xie He
2020-08-10  7:31     ` Willem de Bruijn [this message]
2020-08-10 18:13       ` Xie He
2020-08-16  2:28         ` Xie He
2020-08-19  0:17 ` Xie He
2020-08-19 22:11 ` Xie He

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