linux-kernel - Re: [PATCH 2/5] cpufreq: governor: Create separate sysfs-ops

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Date:	Wed, 3 Feb 2016 18:51:40 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	"Rafael J. Wysocki" <rafael@...nel.org>
Cc:	Rafael Wysocki <rjw@...ysocki.net>,
	Juri Lelli <juri.lelli@....com>,
	Lists linaro-kernel <linaro-kernel@...ts.linaro.org>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	Saravana Kannan <skannan@...eaurora.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Michael Turquette <mturquette@...libre.com>,
	Steve Muckle <steve.muckle@...aro.org>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Morten Rasmussen <morten.rasmussen@....com>,
	dietmar.eggemann@....com,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/5] cpufreq: governor: Create separate sysfs-ops

On 03-02-16, 13:42, Rafael J. Wysocki wrote:
> > +static ssize_t governor_show(struct kobject *kobj, struct attribute *attr,
> > +                            char *buf)
> > +{
> > +       struct dbs_data *dbs_data = to_dbs_data(kobj);
> > +       struct governor_attr *gattr = to_gov_attr(attr);
> > +       int ret = -EIO;
> > +
> > +       down_read(&dbs_data->rwsem);
> > +
> > +       if (gattr->show)
> > +               ret = gattr->show(dbs_data, buf);
> > +
> > +       up_read(&dbs_data->rwsem);
> 
> Do we need the lock here too?
> 
> show() is only going to read the value, isn't it?  And everything u32
> or smaller is read atomically anyway.

Okay, will drop it for now.

> Apart from this it looks good to me.
> 
> When you're ready, please resend the whole series without patch [5/5]
> which is premature IMO.

I have changed that patch a bit, and am dropping just the lock now and
not governor_enable thing. That should be sane enough I believe.

Anyway I will be posting 7 patches now, pick only first 4 if you
aren't confident about the rest.

-- 
viresh