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Tue, 09 Mar 2021 08:20:24 -0800 (PST) Subject: Re: [PATCH 08/11] PM / devfreq: check get_dev_status in devfreq_update_stats To: Dong Aisheng , linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: dongas86@gmail.com, kernel@pengutronix.de, shawnguo@kernel.org, linux-imx@nxp.com, linux-kernel@vger.kernel.org, myungjoo.ham@samsung.com, kyungmin.park@samsung.com, cw00.choi@samsung.com, abel.vesa@nxp.com References: <1615294733-22761-1-git-send-email-aisheng.dong@nxp.com> <1615294733-22761-9-git-send-email-aisheng.dong@nxp.com> From: Chanwoo Choi Message-ID: <0b6ceb75-040f-8e1c-73ea-9d60344b9918@gmail.com> Date: Wed, 10 Mar 2021 01:20:12 +0900 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <1615294733-22761-9-git-send-email-aisheng.dong@nxp.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21. 3. 9. 오후 9:58, Dong Aisheng wrote: > Check .get_dev_status() in devfreq_update_stats in case it's abused > when a device does not provide it. > > Signed-off-by: Dong Aisheng > --- > drivers/devfreq/governor.h | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/devfreq/governor.h b/drivers/devfreq/governor.h > index 31af6d072a10..67a6dbdd5d23 100644 > --- a/drivers/devfreq/governor.h > +++ b/drivers/devfreq/governor.h > @@ -89,6 +89,9 @@ int devfreq_update_target(struct devfreq *devfreq, unsigned long freq); > > static inline int devfreq_update_stats(struct devfreq *df) > { > + if (!df->profile->get_dev_status) > + return -EINVAL; > + I'm considering the following method instead of returning the error when .get_dev_status is NULL. if (!df->profile->get_dev_status) { df->last_status.total_time = 0; df->last_status.busy_time = 0; df->last_status.current_frequency = 0; return 0; } > return df->profile->get_dev_status(df->dev.parent, &df->last_status); > } > #endif /* _GOVERNOR_H */ > -- Best Regards, Samsung Electronics Chanwoo Choi