From b4718c02f49ab5e1452353f0fae78beabe81467c Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Tue, 16 Dec 2014 15:09:38 -0800 Subject: [PATCH] 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 Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/base/power/opp.c | 15 ++++++++------- 1 file 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); -- 2.20.1