From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chanwoo Choi Subject: Re: [PATCH v2] PM / devfreq: Restart previous governor if new governor fails to start Date: Wed, 26 Oct 2016 16:22:48 +0900 Message-ID: <581059C8.3000408@samsung.com> References: <1477445160-990-1-git-send-email-skannan@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Return-path: In-reply-to: <1477445160-990-1-git-send-email-skannan@codeaurora.org> Sender: linux-kernel-owner@vger.kernel.org To: Saravana Kannan , "Rafael J. Wysocki" , MyungJoo Ham , Kyungmin Park , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-pm@vger.kernel.org Hi, On 2016년 10월 26일 10:25, Saravana Kannan wrote: > If the new governor fails to start, switch back to old governor so that the > devfreq state is not left in some weird limbo. > > Signed-off-by: Saravana Kannan > --- > * Fixed typo in commit text > * Fixed potential NULL deref > > drivers/devfreq/devfreq.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c > index bf3ea76..243253e 100644 > --- a/drivers/devfreq/devfreq.c > +++ b/drivers/devfreq/devfreq.c > @@ -919,7 +919,7 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr, > struct devfreq *df = to_devfreq(dev); > int ret; > char str_governor[DEVFREQ_NAME_LEN + 1]; > - struct devfreq_governor *governor; > + const struct devfreq_governor *governor, *prev_gov; > > ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor); > if (ret != 1) > @@ -944,12 +944,17 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr, > goto out; > } > } > + prev_gov = df->governor; > df->governor = governor; > strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN); > ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL); > - if (ret) > + if (ret) { > dev_warn(dev, "%s: Governor %s not started(%d)\n", > __func__, df->governor->name, ret); > + df->governor = prev_gov; > + strncpy(df->governor_name, prev_gov->name, DEVFREQ_NAME_LEN); > + df->governor->event_handler(df, DEVFREQ_GOV_START, NULL); > + } > out: > mutex_unlock(&devfreq_list_lock); > > Looks good to me. But, how about using the 'prev_governor' instead of 'prev_gov'? because the variable name of current governor is 'governor' instead of 'gov'. Reviewed-by: Chanwoo Choi -- Best Regards, Chanwoo Choi