Messages in this thread | | | Date | Mon, 22 Feb 2021 08:14:07 +0100 | From | Martin Schiller <> | Subject | Re: [PATCH net-next RFC v4] net: hdlc_x25: Queue outgoing LAPB frames |
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On 2021-02-19 21:28, Xie He wrote: > On Fri, Feb 19, 2021 at 10:39 AM Jakub Kicinski <kuba@kernel.org> > wrote: >> >> Not entirely sure what the argument is about but adding constants >> would >> certainly help. > > Leon wants me to replace this: > > dev->needed_headroom = 3 - 1; > > with this: > > /* 2 is the result of 3 - 1 */ > dev->needed_headroom = 2; > > But I don't feel his way is better than my way. > >> More fundamentally IDK if we can make such a fundamental change here. >> When users upgrade from older kernel are all their scripts going to >> work the same? Won't they have to bring the new netdev up? > > Yes, this patch will break backward compatibility. Users with old > scripts will find them no longer working. > > However, it's hard for me to find a better way to solve the problem > described in the commit message. > > So I sent this as an RFC to see what people think about this. (Martin > Schiller seems to be OK with this.)
Well, I said I would like to test it.
I'm not really happy with this change because it breaks compatibility. We then suddenly have 2 interfaces; the X.25 routings are to be set via the "new" hdlc<x>_x25 interfaces instead of the hdlc<x> interfaces.
I currently just don't have a nicer solution to fix this queueing problem either. On the other hand, since the many years we have been using the current state, I have never noticed any problems with discarded frames. So it might be more a theoretical problem than a practical one.
> > I think users who don't use scripts can adapt quickly and users who > use scripts can also trivally fix their scripts. > > Actually many existing commits in the kernel also (more or less) cause > some user-visible changes. But I admit this patch is a really big > change.
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