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From: "H. Peter Anvin" <hpa@zytor.com>
To: Arjan van de Ven <arjan@infradead.org>
Cc: Russell King <rmk+lkml@arm.linux.org.uk>,
	Linux Kernel List <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@elte.hu>
Subject: Re: lockdep: results on ARM
Date: Thu, 27 Jul 2006 13:46:40 -0700	[thread overview]
Message-ID: <44C92630.403@zytor.com> (raw)
In-Reply-To: <1154010723.3039.59.camel@laptopd505.fenrus.org>

Arjan van de Ven wrote:
> On Thu, 2006-07-27 at 15:24 +0100, Russell King wrote:
>> +#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
>> +	p->hardirqs_enabled = 1;
>> +#else
>>  	p->hardirqs_enabled = 0;
>> +#endif
> 
> if __ARCH_WANT_INTERRUPTS_ON_CTXSW is set to 1 for arm you can turn this
> into
> 
> p->hardirqs_enabled = __ARCH_WANT_INTERRUPTS_ON_CTXSW + 0;
> 
> and save the ifdef ;)
> 

#ifdef is actually really evil.  It's much cleaner to use #if and make 
sure everything defines either 0 or 1.  Partially because it often makes 
you not have to add an #if at all, but also because it makes it 
immediately obvious if some definition was missed.

	-hpa

      reply	other threads:[~2006-07-27 20:49 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-07-27 14:24 lockdep: results on ARM Russell King
2006-07-27 14:23 ` Ingo Molnar
2006-07-27 14:32 ` Arjan van de Ven
2006-07-27 20:46   ` H. Peter Anvin [this message]

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