From: David Brownell <david-b@pacbell.net>
To: stephen@streetfiresound.com
Subject: Re: [PATCH] spi: Fix modular master driver remove and device suspend/remove
Date: Tue, 7 Feb 2006 13:56:29 -0800
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Cc: Russell King <rmk+lkml@arm.linux.org.uk>, greg@kroah.com,
       linux-kernel@vger.kernel.org, dvrabel@arcom.com
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On Tuesday 07 February 2006 1:35 pm, Stephen Street wrote:
> On Tue, 2006-02-07 at 08:03 +0000, Russell King wrote:

> > > @@ -90,7 +90,7 @@ static int spi_suspend(struct device *de
> > >  	int			value;
> > >  	struct spi_driver	*drv = to_spi_driver(dev->driver);
> > >  
> > > -	if (!drv->suspend)
> > > +	if (!drv || !drv->suspend)
> > 
> > Shouldn't this be dev->driver ?  If dev->driver is NULL, drv may be
> > non-NULL due to an offset in the structure.
> > 
> If I understand your comment correctly, the implementation of to_spi_drv
> protects against this by returning NULL if dev->driver is NULL. This is
> implementation dependent 

I'd say that to_spi_driver() is defined that way, specifically
to avoid that class of nasty bug.

> and I can make the test explicit if you want? 
> 
-
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