Re: [PATCH 2.6.20-rc5] SPI: alternative fix for spi_busnum_to_master

[Atsushi Nemoto <anemo@mba.ocn.ne.jp>]

On Mon, 22 Jan 2007 14:12:02 -0800, David Brownell <david-b@pacbell.net> wrote:
> > Here is a revised version.  The children list of spi_master_class
> > contains only spi_master class so we can just compare bus_num member
> > instead of class_id string.
> 
> Looks just a bit iffy ... though, thanks for helping to finally
> sort this out!

Well, so previous patch (which was checking class_id string) would be
preferred?

> > +		cdev = class_device_get(cdev);
> > +		if (!cdev)
> > +			continue;
> 
> That "continue" case doesn't seem like it should be possible... but
> at any rate, the "get" can be deferred until the relevent class
> device is known, since that _valid_ handle can't disappear so long
> as that semaphore is held.  And if you find the right device but
> can't get a reference ... no point in continuing!
> 
> Something like a class_find_device() would be the best way to solve
> this sort of problem, IMO.  But we don't have one of those.  :(

Indeed the check can be omitted.  Should I send a new patch just
moving class_device_get() into "if (master->bus_num == bus_num)"
block?

The crashing with udev is 2.6.20 regression so I wish this fixed very
soon.  Thank you for review.

---
Atsushi Nemoto
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