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authorDmitry Torokhov <dtor@chromium.org>2014-12-17 02:09:38 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2014-12-18 03:42:49 +0300
commitb4718c02f49ab5e1452353f0fae78beabe81467c (patch)
tree7eb5b9f28f79d6cb0d43f5b6ea62d77eac6806a4 /drivers/base
parent0fe30da2cb43782ee62d30c00a273d6934e5370e (diff)
downloadlinux-b4718c02f49ab5e1452353f0fae78beabe81467c.tar.xz
PM / OPP: take RCU lock in dev_pm_opp_get_opp_count
A lot of callers are missing the fact that dev_pm_opp_get_opp_count needs to be called under RCU lock. Given that RCU locks can safely be nested, instead of providing *_locked() API, let's take RCU lock inside dev_pm_opp_get_opp_count() and leave callers as is. Signed-off-by: Dmitry Torokhov <dtor@chromium.org> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/base')
-rw-r--r--drivers/base/power/opp.c15
1 files changed, 8 insertions, 7 deletions
diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index aac7abcf74f8..106c69359306 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -216,9 +216,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq);
* This function returns the number of available opps if there are any,
* else returns 0 if none or the corresponding error value.
*
- * Locking: This function must be called under rcu_read_lock(). This function
- * internally references two RCU protected structures: device_opp and opp which
- * are safe as long as we are under a common RCU locked section.
+ * Locking: This function takes rcu_read_lock().
*/
int dev_pm_opp_get_opp_count(struct device *dev)
{
@@ -226,13 +224,14 @@ int dev_pm_opp_get_opp_count(struct device *dev)
struct dev_pm_opp *temp_opp;
int count = 0;
- opp_rcu_lockdep_assert();
+ rcu_read_lock();
dev_opp = find_device_opp(dev);
if (IS_ERR(dev_opp)) {
- int r = PTR_ERR(dev_opp);
- dev_err(dev, "%s: device OPP not found (%d)\n", __func__, r);
- return r;
+ count = PTR_ERR(dev_opp);
+ dev_err(dev, "%s: device OPP not found (%d)\n",
+ __func__, count);
+ goto out_unlock;
}
list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) {
@@ -240,6 +239,8 @@ int dev_pm_opp_get_opp_count(struct device *dev)
count++;
}
+out_unlock:
+ rcu_read_unlock();
return count;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count);