linux-kernel - Re: [PATCH 1/1] cpuidle: coupled: fix ready counter decrement

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Message-ID: <4511257.Msp501Wi5G@vostro.rjw.lan>
Date:	Sat, 15 Dec 2012 00:37:03 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Sivaram Nair <sivaramn@...dia.com>
Cc:	ccross@...roid.com, santosh.shilimkar@...com, khilman@...com,
	daniel.lezcano@...aro.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] cpuidle: coupled: fix ready counter decrement

On Friday, December 14, 2012 10:42:08 AM Sivaram Nair wrote:
> The ready_waiting_counts atomic variable is compared against the wrong
> online cpu count. The latter is computed incorrectly using logical-OR
> instead of bit-OR. This patch fixes that.

I'm queuing this up for submission as v3.8 material.

I suppose it should be marked for -stable too?

Rafael


> Signed-off-by: Sivaram Nair <sivaramn@...dia.com>
> ---
>  drivers/cpuidle/coupled.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c
> index 3265844..2a297f8 100644
> --- a/drivers/cpuidle/coupled.c
> +++ b/drivers/cpuidle/coupled.c
> @@ -209,7 +209,7 @@ inline int cpuidle_coupled_set_not_ready(struct cpuidle_coupled *coupled)
>  	int all;
>  	int ret;
>  
> -	all = coupled->online_count || (coupled->online_count << WAITING_BITS);
> +	all = coupled->online_count | (coupled->online_count << WAITING_BITS);
>  	ret = atomic_add_unless(&coupled->ready_waiting_counts,
>  		-MAX_WAITING_CPUS, all);
>  
> 
-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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