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Subject[PATCH 1/4] PM / OPP: add some lockdep annotations
Date
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>
---
drivers/base/power/opp.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)

diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index d24dd614a..b78c14d 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
@@ -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);
--
2.2.0.rc0.207.ga3a616c


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