linux-kernel - Re: [PATCH] firmware: Do not use WARN_ON(!spin_is

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Message-ID: <20140813144458.GS9918@twins.programming.kicks-ass.net>
Date:	Wed, 13 Aug 2014 16:44:58 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Matt Fleming <matt@...sole-pimps.org>
Cc:	Guenter Roeck <linux@...ck-us.net>,
	Matt Fleming <matt.fleming@...el.com>,
	linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] firmware: Do not use WARN_ON(!spin_is_locked())

On Wed, Aug 13, 2014 at 03:18:36PM +0100, Matt Fleming wrote:
> On Sun, 10 Aug, at 08:54:13PM, Guenter Roeck wrote:
> > spin_is_locked() always returns false for uniprocessor configurations,
> > so do not use WARN_ON with it. WARN_ON_SMP() exists for that very
> > purpose and must be used instead.
>  
> 
> How about lockdep_assert_held()? That seems to be much more popular.

lockdep_assert_held() not only checks if the lock is taken, it also
verifies its taken by the current context, so its a stronger assertion.

And, as a bonus, it doesn't emit _any_ code on a !DEBUG build ;-)

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