linux-kernel - Re: [PATCH] PM / devfreq: Fix faulty error message

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Date:	Wed, 18 Mar 2015 04:12:34 +0000 (GMT)
From:	MyungJoo Ham <myungjoo.ham@...sung.com>
To:	Deva Ramasubramanian <dramasub@...eaurora.org>
Cc:	박경민 <kyungmin.park@...sung.com>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] PM / devfreq: Fix faulty error message

> The misleading log "releasing devfreq which doesn't exist" prints out
> for well behaved clients.  This is due to the fact that _remove_devfreq
> calls itself recursively by proxy (via put_device()).  The second time
> _devfreq_remove is called the respective device has already been
> deleted, causing the misleading warning.
> 
> So just skip printing the message if _devfreq_remove was called via
> put_device().
> 
> Signed-off-by: Deva Ramasubramanian <dramasub@...eaurora.org>
> ---
>  drivers/devfreq/devfreq.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index 30b538d8..bee59db 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -399,7 +399,8 @@ static void _remove_devfreq(struct devfreq *devfreq)
>  	mutex_lock(&devfreq_list_lock);
>  	if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) {
>  		mutex_unlock(&devfreq_list_lock);
> -		dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n");
> +		if (!skip)
> +			dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n");

There is no variable 'skip' in the function. (you get build error.)
And with patch 585fc83ece43be63, we do not call the function recursively, either.

---
drivers/devfreq/devfreq.c: In function ‘_remove_devfreq’:
drivers/devfreq/devfreq.c:402:8: error: ‘skip’ undeclared (first use in this function)
drivers/devfreq/devfreq.c:402:8: note: each undeclared identifier is reported only once for each function it appears in
make[2]: *** [drivers/devfreq/devfreq.o] Error 1
make[1]: *** [drivers/devfreq] Error 2
make[1]: *** Waiting for unfinished jobs....
---

I'll update the function description.


Cheers,
MyungJoo.

>  		return;
>  	}
>  	list_del(&devfreq->node);
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project