[illumos-Developer] [REVIEW] 260 some drivers erroneously discount a major of 0

[Garrett D'Amore]

dump(7d) uses major 0 on my system.  I think we just have recognize that
0 is a valid major number.

	- Garrett

On Thu, 2010-09-30 at 21:52 -0400, Gordon Ross wrote:
> Looks fine to me.
> 
> I wonder if there is any reasonable way on an existing system to move
> whatever driver might be using major zero to some other major number?
> If so, you could skip the 2nd and 3rd file changes.
> 
> On Tue, Sep 28, 2010 at 1:36 AM, Richard Lowe <richlowe at richlowe.net> wrote:
> >
> > I'd like review of:
> >   260 some drivers erroneously discount a major of 0
> >
> > webrev: http://richlowe.net/webrevs/il-maj0/
> >
> > This bug is the same as:
> >  6975280 t_kopen() fails if transport major device = 0
> >
> > As noted in the bug (#260), the change to add_drv prevents major 0 being
> > given to drivers (it means, for new images, major numbers will start
> > from 1), this is due to the impossibility of auditing every driver for
> > assumptions regarding (dev_t)0 (especially those from 3rd parties), and
> > the apparently fairly widespread assumption that such a dev_t is
> > invalid.  The only code I found with such assumptions is t_kopen, and in
> > addition sv, as mentioned in the bug.
> >
> > I've tested this via add_drv -b, with an empty name_to_major, to verify
> > that the first driver it adds gets major 1, with a partially complete
> > name_to_major, to make sure that the 'gap' at 0 is not filled, and by
> > wiring tcp(7D) to major 0 to test the circumstances mentioned in 6975280
> > (both before and after).
> >
> > I have not yet found a good way to test 'sv', though the change seems
> > obvious I'm entirely willing to (and would prefer to) revert it, unless
> > a volunteer can come up with a reasonable way to test it.  You would
> > need the device underlying sv to have both a major and minor number of
> > 0.
> >
> > Garrett has already looked at this, and given some general sense of
> > assent.
> >
> > If you plan to look at this but require more time, please say so,
> > so that I know to wait for you.
> >
> > -- Rich
> >
> > _______________________________________________
> > Developer mailing list
> > Developer at lists.illumos.org
> > http://lists.illumos.org/m/listinfo/developer
> >
> 
> _______________________________________________
> Developer mailing list
> Developer at lists.illumos.org
> http://lists.illumos.org/m/listinfo/developer