PM / OPP: add some lockdep annotations

Certain OPP APIs need to be called under RCU lock; let's add a few
rcu_lockdep_assert() calls to warn about potential misuse.

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>

diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index d24dd614a0bd3208c0d88fd79c35397db5be8a71..b78c14d30da2c095d587f158f494aea2fe2038ea 100644 (file)
--- 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
@@ -218,6 +226,8 @@ int dev_pm_opp_get_opp_count(struct device *dev)
        struct dev_pm_opp *temp_opp;
        int count = 0;
 
+       opp_rcu_lockdep_assert();
+
        dev_opp = find_device_opp(dev);
        if (IS_ERR(dev_opp)) {
                int r = PTR_ERR(dev_opp);
@@ -267,6 +277,8 @@ 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 +325,8 @@ 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 +375,8 @@ 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);