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Subject: Re: [RESEND PATCH] PM / devfreq: Fix static checker warning in
 try_then_request_governor
To:     Enric Balletbo i Serra <enric.balletbo@collabora.com>,
        linux-kernel@vger.kernel.org,
        "stable@vger.kernel.org" <stable@vger.kernel.org>
Cc:     kernel@collabora.com, Dan Carpenter <dan.carpenter@oracle.com>,
        Kyungmin Park <kyungmin.park@samsung.com>,
        MyungJoo Ham <myungjoo.ham@samsung.com>,
        linux-pm@vger.kernel.org
From:   Chanwoo Choi <cw00.choi@samsung.com>
Organization: Samsung Electronics
Message-ID: <4535a997-e583-da83-0cdd-0433dd798f50@samsung.com>
Date:   Tue, 28 May 2019 10:15:59 +0900
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References: <CGME20190313122310epcas4p4152c2c30d7a2971e44ddc7c5b64b7744@epcas4p4.samsung.com>
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Cc: stable@vger.kernel.org

Dear all,

It missed to send this patch to 'stable@vger.kernel.org'.
So, I add it to mailing list.

Regards,
Chanwoo Choi


On 19. 3. 13. 오후 9:22, Enric Balletbo i Serra wrote:
> The patch 23c7b54ca1cd: "PM / devfreq: Fix devfreq_add_device() when
> drivers are built as modules." leads to the following static checker
> warning:
> 
>     drivers/devfreq/devfreq.c:1043 governor_store()
>     warn: 'governor' can also be NULL
> 
> The reason is that the try_then_request_governor() function returns both
> error pointers and NULL. It should just return error pointers, so fix
> this by returning a ERR_PTR to the error intead of returning NULL.
> 
> Fixes: 23c7b54ca1cd ("PM / devfreq: Fix devfreq_add_device() when drivers are built as modules.")
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
> ---
> Hi,
> 
> This is a resend of [1] as seems that got lost at some point and I just
> noticed that was never merged.
> 
> Thanks,
>  Enric
> 
> [1] https://lkml.org/lkml/2018/10/16/744
> 
> 
>  drivers/devfreq/devfreq.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index 0ae3de76833b..839621b044f4 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -228,7 +228,7 @@ static struct devfreq_governor *find_devfreq_governor(const char *name)
>   * if is not found. This can happen when both drivers (the governor driver
>   * and the driver that call devfreq_add_device) are built as modules.
>   * devfreq_list_lock should be held by the caller. Returns the matched
> - * governor's pointer.
> + * governor's pointer or an error pointer.
>   */
>  static struct devfreq_governor *try_then_request_governor(const char *name)
>  {
> @@ -254,7 +254,7 @@ static struct devfreq_governor *try_then_request_governor(const char *name)
>  		/* Restore previous state before return */
>  		mutex_lock(&devfreq_list_lock);
>  		if (err)
> -			return NULL;
> +			return ERR_PTR(err);
>  
>  		governor = find_devfreq_governor(name);
>  	}
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics