From: Martin Schiller <ms@dev.tdt.de>
To: Jakub Kicinski <kubakici@wp.pl>
Cc: khc@pm.waw.pl, davem@davemloft.net, linux-x25@vger.kernel.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] wan/hdlc_x25: make lapb params configurable
Date: Tue, 14 Jan 2020 14:33:51 +0100 [thread overview]
Message-ID: <3b439730f93e29c9e823126b74c2fbd3@dev.tdt.de> (raw)
In-Reply-To: <20200114045149.4e97f0ac@cakuba>
On 2020-01-14 13:51, Jakub Kicinski wrote:
> On Tue, 14 Jan 2020 06:37:03 +0100, Martin Schiller wrote:
>> >> diff --git a/include/uapi/linux/hdlc/ioctl.h
>> >> b/include/uapi/linux/hdlc/ioctl.h
>> >> index 0fe4238e8246..3656ce8b8af0 100644
>> >> --- a/include/uapi/linux/hdlc/ioctl.h
>> >> +++ b/include/uapi/linux/hdlc/ioctl.h
>> >> @@ -3,7 +3,7 @@
>> >> #define __HDLC_IOCTL_H__
>> >>
>> >>
>> >> -#define GENERIC_HDLC_VERSION 4 /* For synchronization with sethdlc
>> >> utility */
>> >> +#define GENERIC_HDLC_VERSION 5 /* For synchronization with sethdlc
>> >> utility */
>> >
>> > What's the backward compatibility story in this code?
>>
>> Well, I thought I have to increment the version to keep the kernel
>> code
>> and the sethdlc utility in sync (like the comment says).
>
> Perhaps I chose the wrong place for asking this question, IOCTL code
> was my real worry. I don't think this version number is validated so
> I think bumping it shouldn't break anything?
sethdlc validates the GENERIC_HDLC_VERSION at compile time.
https://mirrors.edge.kernel.org/pub/linux/utils/net/hdlc/
Another question:
Where do I have to send my patch for sethdlc to?
>
>> > The IOCTL handling at least looks like it may start returning errors
>> > to existing user space which could have expected the parameters to
>> > IF_PROTO_X25 (other than just ifr_settings.type) to be ignored.
>>
>> I could also try to implement it without incrementing the version by
>> looking at ifr_settings.size and using the former defaults if the size
>> doesn't match.
>
> Sounds good, thank you!
OK, I will send a v2 of the patch.
next prev parent reply other threads:[~2020-01-14 13:33 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-13 12:45 [PATCH 1/2] wan/hdlc_x25: make lapb params configurable Martin Schiller
2020-01-13 12:45 ` [PATCH 2/2] wan/hdlc_x25: fix skb handling Martin Schiller
2020-01-13 13:44 ` Jakub Kicinski
2020-01-14 8:10 ` Martin Schiller
2020-01-13 13:53 ` [PATCH 1/2] wan/hdlc_x25: make lapb params configurable Jakub Kicinski
2020-01-14 5:37 ` Martin Schiller
2020-01-14 12:51 ` Jakub Kicinski
2020-01-14 13:33 ` Martin Schiller [this message]
2020-01-14 13:45 ` Jakub Kicinski
2020-03-26 6:08 ` Krzysztof Hałasa
2020-03-26 6:08 ` Krzysztof Hałasa
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