Re: Locking Between User Context and Soft IRQs in 2.4.0

Jeff Garzik
2000-11-06T13:10:37Z

Keith Owens wrote:
>
> On Mon, 06 Nov 2000 07:49:00 -0500,
> Jeff Garzik <jgarzik@mandrakesoft.com> wrote:
> >Keith Owens wrote:
> >> I prefer a requirement that all net drivers upgrade to the new
> >> interface, otherwise we have odd drivers using the old interface
> >> forever and being at risk of module unload. That is why I coded my
> >> patch as returning -ENODEV if there was no dev->open. However I have
> >> to accept that just before a 2.4 release is not the best time to have a
> >> flag day. Put it down for 2.5.
> >
> >What is "it" that gets put off until 2.5? Breaking net drivers with an
> >interface upgrade, or eliminating this race?
>
> Forcing all network drivers to define a dev->open routine.
>
> >There is absolutely no need to break drivers for this. Not only is it
> >needless pain, but doing so is inconsistent -- with struct
> >file_operations, I am free to have owner==NULL.
>
> True, but if you set owner==NULL for something that is really in a
> module then you are lying to the module layer. See foot, shoot foot.

You are missing the point here. If a driver is "old style", where
owner==NULL and it manually calls MOD_{INC,DEC}_USE_COUNT, things are
pretty much ok. There is a tiny race, but the system is mostly intact.

For never drivers "that matter," we update them to set
net_device::owner. But to me breaking all the net drivers to force such
a change is silly. For such a tiny race, there just isn't a pressing
need to update the stinkbomb crapola drivers...

Jeff

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