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Subject: Re: [patch 2.6.25-rc3] lockdep:  add spin_lock_irq_nested()
From: Peter Zijlstra <peterz@infradead.org>
To: David Brownell <david-b@pacbell.net>
Cc: mingo@redhat.com, linux-kernel@vger.kernel.org
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Date: Tue, 26 Feb 2008 10:53:46 +0100
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On Mon, 2008-02-25 at 14:33 -0800, David Brownell wrote:

> > +#ifdef CONFIG_LOCKDEP
> > +
> > +/* tell lockdep that this IRQ's locks and its parent's locks are in
> > + * different categories, so that it won't detect false recursion.
> > + */
> > +static struct lock_class_key gpio_lock_class;
> > +
> > +static inline void mark_gpio_locking(unsigned gpio_irq)
> > +{
> > +	lockdep_set_class(&irq_desc[gpio_irq].lock, &gpio_lock_class);
> > +}
> > +
> > +#else
> > +
> > +static inline void mark_gpio_locking(unsigned gpio_irq)
> > +{
> > +	/* NOP */
> > +}
> > +
> > +#endif

Glad to hear this works out for you.

Just one note, you don't need the #ifdef mess here. struct
lock_class_key is 0 bytes on !LOCKDEP and lockdep_set_class*() is
defined away as well.