From: Viresh Kumar <viresh.kumar@linaro.org>
To: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: Rafael Wysocki <rjw@rjwysocki.net>,
linaro-kernel@lists.linaro.org, linux-pm@vger.kernel.org,
ego@linux.vnet.ibm.com, paulus@samba.org,
shilpa.bhat@linux.vnet.ibm.com, prarit@redhat.com,
robert.schoene@tu-dresden.de, skannan@codeaurora.org
Subject: Re: [PATCH 2/3] cpufreq: governor: split cpufreq_governor_dbs()
Date: Thu, 4 Jun 2015 15:47:06 +0530 [thread overview]
Message-ID: <20150604101706.GB743@linux> (raw)
In-Reply-To: <5570229F.3080808@linux.vnet.ibm.com>
On 04-06-15, 15:34, Preeti U Murthy wrote:
> > + if (dbs_data) {
> > + WARN_ON(have_governor_per_policy());
>
> Shouldn't this be outside this loop ? We warn here and allocate dbs_dta
Loop ? Its just an 'if' block :)
> freshly in the current code for the case where governor is per policy.
So what we are doing in the current code is equally disgusting. We
already have a pointer and we overwrite it.
>
> > + dbs_data->usage_count++;
>
> Besides, in the case where a governor exists per policy, we will end up
> incrementing the usage_count to more than 1 under this condition, which
> does not make sense.
So, the only sane option here is to return an error immediately I
think.
diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index ed849a8777dd..57a39f8a92b7 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -247,7 +247,8 @@ static int cpufreq_governor_init(struct cpufreq_policy *policy,
int ret;
if (dbs_data) {
- WARN_ON(have_governor_per_policy());
+ if (WARN_ON(have_governor_per_policy()))
+ return -EINVAL;
dbs_data->usage_count++;
policy->governor_data = dbs_data;
return 0;
@@ -276,24 +277,28 @@ static int cpufreq_governor_init(struct cpufreq_policy *policy,
latency * LATENCY_MULTIPLIER));
if (!have_governor_per_policy()) {
- WARN_ON(cpufreq_get_global_kobject());
+ if (WARN_ON(cpufreq_get_global_kobject())) {
+ ret = -EINVAL;
+ goto cdata_exit;
+ }
cdata->gdbs_data = dbs_data;
}
ret = sysfs_create_group(get_governor_parent_kobj(policy),
get_sysfs_attr(dbs_data));
if (ret)
- goto cdata_exit;
+ goto put_kobj;
policy->governor_data = dbs_data;
return 0;
-cdata_exit:
+put_kobj:
if (!have_governor_per_policy()) {
cdata->gdbs_data = NULL;
cpufreq_put_global_kobject();
}
+cdata_exit:
cdata->exit(dbs_data, !policy->governor->initialized);
free_dbs_data:
kfree(dbs_data);
--
viresh
next prev parent reply other threads:[~2015-06-04 10:17 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-03 10:27 [PATCH 0/3] cpufreq: governor: Fix potential races Viresh Kumar
2015-06-03 10:27 ` [PATCH 1/3] cpufreq: governor: register notifier from cs_init() Viresh Kumar
2015-06-04 5:38 ` Preeti U Murthy
2015-06-04 6:02 ` Viresh Kumar
2015-06-04 7:33 ` Preeti U Murthy
2015-06-03 10:27 ` [PATCH 2/3] cpufreq: governor: split cpufreq_governor_dbs() Viresh Kumar
2015-06-04 10:04 ` Preeti U Murthy
2015-06-04 10:17 ` Viresh Kumar [this message]
2015-06-04 11:13 ` [PATCH V2 " Viresh Kumar
2015-06-05 2:51 ` Preeti U Murthy
2015-06-03 10:27 ` [PATCH 3/3] cpufreq: governor: Serialize governor callbacks Viresh Kumar
2015-06-04 10:47 ` Preeti U Murthy
2015-06-04 5:14 ` [PATCH 0/3] cpufreq: governor: Fix potential races Preeti U Murthy
2015-06-04 6:08 ` Preeti U Murthy
2015-06-04 6:11 ` Viresh Kumar
2015-06-04 6:36 ` Preeti U Murthy
2015-06-04 6:42 ` Viresh Kumar
2015-06-04 7:04 ` Preeti U Murthy
2015-06-04 7:13 ` Viresh Kumar
2015-06-04 7:27 ` Preeti U Murthy
2015-06-05 3:00 ` Viresh Kumar
2015-06-05 3:04 ` Preeti U Murthy
2015-06-05 4:05 ` Preeti U Murthy
2015-06-15 23:48 ` Rafael J. Wysocki
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20150604101706.GB743@linux \
--to=viresh.kumar@linaro.org \
--cc=ego@linux.vnet.ibm.com \
--cc=linaro-kernel@lists.linaro.org \
--cc=linux-pm@vger.kernel.org \
--cc=paulus@samba.org \
--cc=prarit@redhat.com \
--cc=preeti@linux.vnet.ibm.com \
--cc=rjw@rjwysocki.net \
--cc=robert.schoene@tu-dresden.de \
--cc=shilpa.bhat@linux.vnet.ibm.com \
--cc=skannan@codeaurora.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.