Re: linux-next: build warning after merge of the rcu tree

From: Arnaud Lacombe
Date: Wed Aug 24 2011 - 20:46:24 EST


Hi,

On Wed, Aug 24, 2011 at 8:27 AM, Paul E. McKenney
<paulmck@xxxxxxxxxxxxxxxxxx> wrote:
> On Wed, Aug 24, 2011 at 02:23:37PM +1000, Stephen Rothwell wrote:
>> Hi Paul,
>>
>> After merging the rcu tree, today's linux-next build (powerpc
>> ppc64_defconfig) produced this warning:
>>
>> kernel/rtmutex.c: In function '__rt_mutex_slowlock':
>> kernel/rtmutex.c:605:3: warning: suggest parentheses around assignment used as truth value
>
> There actually already are parentheses around it, and the first pass
> through the loop it is uninitialized at that point.  But hey, that
> is gcc for you!  Does the patch below cure it?
>
Yes.

- Arnaud

>> Introduced by commit 83841f021d4b ("rcu: Permit rt_mutex_unlock() with
>> irqs disabled").
>
> If it does, then I will fold into that commit.
>
>                                                        Thanx, Paul
>
> ------------------------------------------------------------------------
>
> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
>
> diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
> index 0222e34..2548f44 100644
> --- a/kernel/rtmutex.c
> +++ b/kernel/rtmutex.c
> @@ -602,7 +602,8 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
>
>                raw_spin_unlock(&lock->wait_lock);
>
> -               if (was_disabled = irqs_disabled())
> +               was_disabled = irqs_disabled();
> +               if (was_disabled)
>                        local_irq_enable();
>
>                debug_rt_mutex_print_deadlock(waiter);
> --
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