diff options
| -rw-r--r-- | drivers/base/power/opp.c | 39 |
1 files changed, 31 insertions, 8 deletions
diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c index d24dd614a0bd..106c69359306 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); |