From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <peterz@infradead.org>
Date: Wed, 22 Oct 2008 08:45:27 +0000
Subject: Re: [PATCH 1/2] Allow rwlocks to re-enable interrupts
Message-Id: <1224665128.15448.4.camel@twins>
List-Id: <linux-ia64.vger.kernel.org>
References: <1224664414.4430.33.camel@elijah.suse.cz>
	 <1224664476.4430.38.camel@elijah.suse.cz>
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To: Petr Tesarik <ptesarik@suse.cz>
Cc: linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, tee@sgi.com, Ingo Molnar <mingo@elte.hu>

On Wed, 2008-10-22 at 10:34 +0200, Petr Tesarik wrote:
> c b/kernel/spinlock.c
> index 29ab207..f769d8a 100644
> --- a/kernel/spinlock.c
> +++ b/kernel/spinlock.c
> @@ -121,7 +121,11 @@ unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock)
>  	local_irq_save(flags);
>  	preempt_disable();
>  	rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
> +#ifdef CONFIG_LOCKDEP
>  	LOCK_CONTENDED(lock, _raw_read_trylock, _raw_read_lock);
> +#else
> +	_raw_read_lock_flags(lock, &flags);
> +#endif
>  	return flags;
>  }

That should be CONFIG_LOCK_STAT.

But aside from that, I really don't like this change, I'd rather you'd
create a LOCK_CONTENDED_FLAGS() that can deal with this.