Merge tag 'pm+acpi-3.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management and ACPI material from Rafael J Wysocki:
 "These are fixes (operating performance points library, cpufreq-dt
  driver, cpufreq core, ACPI backlight, cpupower tool), cleanups
  (cpuidle), new processor IDs for the RAPL (Running Average Power
  Limit) power capping driver, and a modification of the generic power
  domains framework allowing modular drivers to call one of its helper
  functions.

  Specifics:

   - Fix for a potential NULL pointer dereference in the cpufreq core
     due to an initialization race condition (Ethan Zhao).

   - Fixes for abuse of the OPP (Operating Performance Points) API
     related to RCU and other minor issues in the OPP library and the
     cpufreq-dt driver (Dmitry Torokhov).

   - cpuidle governors cleanup making them measure idle duration in a
     better way without using the CPUIDLE_FLAG_TIME_INVALID flag which
     allows that flag to be dropped from the ACPI cpuidle driver and
     from the core too (Len Brown).

   - New ACPI backlight blacklist entries for Samsung machines without a
     working native backlight interface that need to use the ACPI
     backlight instead (Aaron Lu).

   - New CPU IDs of future Intel Xeon CPUs for the Intel RAPL power
     capping driver (Jacob Pan).

   - Generic power domains framework modification to export the
     of_genpd_get_from_provider() function to modular drivers that will
     allow future driver modifications to be based on the mainline (Amit
     Daniel Kachhap).

   - Two fixes for the cpupower tool (Michal Privoznik, Prarit
     Bhargava)"

* tag 'pm+acpi-3.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / video: Add some Samsung models to disable_native_backlight list
  tools / cpupower: Fix no idle state information return value
  tools / cpupower: Correctly detect if running as root
  cpufreq: fix a NULL pointer dereference in __cpufreq_governor()
  cpufreq-dt: defer probing if OPP table is not ready
  PM / OPP: take RCU lock in dev_pm_opp_get_opp_count
  PM / OPP: fix warning in of_free_opp_table()
  PM / OPP: add some lockdep annotations
  powercap / RAPL: add IDs for future Xeon CPUs
  PM / Domains: Export of_genpd_get_from_provider function
  cpuidle / ACPI: remove unused CPUIDLE_FLAG_TIME_INVALID
  cpuidle: ladder: Better idle duration measurement without using CPUIDLE_FLAG_TIME_INVALID
  cpuidle: menu: Better idle duration measurement without using CPUIDLE_FLAG_TIME_INVALID

1 files changed, 31 insertions, 8 deletions

diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index d24dd614a0b..106c6935930 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -108,6 +108,14 @@ static LIST_HEAD(dev_opp_list);
 /* Lock to allow exclusive modification to the device and opp lists */
 static DEFINE_MUTEX(dev_opp_list_lock);
 
+#define opp_rcu_lockdep_assert()					\
+do {									\
+	rcu_lockdep_assert(rcu_read_lock_held() ||			\
+				lockdep_is_held(&dev_opp_list_lock),	\
+			   "Missing rcu_read_lock() or "		\
+			   "dev_opp_list_lock protection");		\
+} while (0)
+
 /**
  * find_device_opp() - find device_opp struct using device pointer
  * @dev:	device pointer used to lookup device OPPs
@@ -208,9 +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)
 {
@@ -218,11 +224,14 @@ int dev_pm_opp_get_opp_count(struct device *dev)
 	struct dev_pm_opp *temp_opp;
 	int count = 0;
 
+	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) {
@@ -230,6 +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);
@@ -267,6 +278,8 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
 	struct device_opp *dev_opp;
 	struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
 
+	opp_rcu_lockdep_assert();
+
 	dev_opp = find_device_opp(dev);
 	if (IS_ERR(dev_opp)) {
 		int r = PTR_ERR(dev_opp);
@@ -313,6 +326,8 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
 	struct device_opp *dev_opp;
 	struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
 
+	opp_rcu_lockdep_assert();
+
 	if (!dev || !freq) {
 		dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
 		return ERR_PTR(-EINVAL);
@@ -361,6 +376,8 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
 	struct device_opp *dev_opp;
 	struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
 
+	opp_rcu_lockdep_assert();
+
 	if (!dev || !freq) {
 		dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
 		return ERR_PTR(-EINVAL);
@@ -783,9 +800,15 @@ void of_free_opp_table(struct device *dev)
 
 	/* Check for existing list for 'dev' */
 	dev_opp = find_device_opp(dev);
-	if (WARN(IS_ERR(dev_opp), "%s: dev_opp: %ld\n", dev_name(dev),
-		 PTR_ERR(dev_opp)))
+	if (IS_ERR(dev_opp)) {
+		int error = PTR_ERR(dev_opp);
+		if (error != -ENODEV)
+			WARN(1, "%s: dev_opp: %d\n",
+			     IS_ERR_OR_NULL(dev) ?
+					"Invalid device" : dev_name(dev),
+			     error);
 		return;
+	}
 
 	/* Hold our list modification lock here */
 	mutex_lock(&dev_opp_list_lock);