Date: Thu, 24 May 2001 11:06:57 +0100 (BST) From: Doug Rabson <dfr@nlsystems.com> To: Brian Somers <brian@Awfulhak.org> Cc: Mike Smith <msmith@FreeBSD.ORG>, <freebsd-arch@FreeBSD.ORG> Subject: Re: RFC: unit_list routines Message-ID: <Pine.BSF.4.33.0105241105060.58788-100000@herring.nlsystems.com> In-Reply-To: <200105232020.f4NKK2F10389@hak.lan.Awfulhak.org>
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On Wed, 23 May 2001, Brian Somers wrote:
> > > > > >I didn't do it that way because the ``usual'' way units are allocated
> > > > > >is sequentially. Using bits when there are large numbers of units
> > > > > >gets awkward. I figured what was required was something small and
> > > > > >simple that would cover the requirements of most/all drivers that
> > > > > >need to track their units so that it's easy to find an unused one,
> > > > > >and it's easy to allocate/deallocate things.
> > > > >
> > > > > How does newbus allocate/manage unit numbers ?
> > > >
> > > > I don't think it does. The only way to find out what's in use
> > > > (AFAIK) is by looking at every specinfo in dev_hash....
> > >
> > > Er, what exactly are you smoking?
> > >
> > > Newbus manages unit numbers using the devclass:
> > >
> > > struct devclass {
> > > TAILQ_ENTRY(devclass) link;
> > > driver_list_t drivers; /* bus devclasses store drivers for bus */
> > > char *name;
> > > device_t *devices; /* array of devices indexed by unit */
> > > int maxunit; /* size of devices array */
> > > };
> >
> > Yes, Garrett pointed this out. I misunderstood the question because
> > newbus doesn't manage unit numbers. It ``manages'' the maximum unit
> > number allocated and nothing else.
> >
> > My answer was describing the only way I know of to figure out which
> > units for a given device are allocated/opened.
>
> Hmm, hang on. I'll stop smoking.... If that device_t array knows
> which devices are open it could solve my problems...
This object will not help you unless we rewrite the pseudo devices to use
newbus. You don't have a device_t instance for your tunX instance. I can
think of good reasons for wanting to represent pseudo devices with newbus
but it doesn't work that way right now.
--
Doug Rabson Mail: dfr@nlsystems.com
Phone: +44 20 8348 6160
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