diff mbox

PM / OPP: add some lockdep annotations

Message ID 20141216004204.GA30467@dtor-ws (mailing list archive)
State Superseded, archived
Headers show

Commit Message

Dmitry Torokhov Dec. 16, 2014, 12:42 a.m. UTC 
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 | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

Comments

Viresh Kumar Dec. 16, 2014, 5:31 a.m. UTC | #1 
On 16 December 2014 at 06:12, Dmitry Torokhov <dtor@chromium.org> wrote:
> Certain OPP APIs need to be called under RCU lock; let's add a few
> rcu_lockdep_assert() calls to warn about potential misuse.

Very nice..

> Signed-off-by: Dmitry Torokhov <dtor@chromium.org>
> ---
>  drivers/base/power/opp.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
>
> diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
> index d24dd614a..852eebf 100644
> --- a/drivers/base/power/opp.c
> +++ b/drivers/base/power/opp.c
> @@ -218,6 +218,11 @@ int dev_pm_opp_get_opp_count(struct device *dev)
>         struct dev_pm_opp *temp_opp;
>         int count = 0;
>
> +       rcu_lockdep_assert(rcu_read_lock_held() ||
> +                               lockdep_is_held(&dev_opp_list_lock),
> +                          "dev_pm_opp_get_opp_count() needs rcu_read_lock() "
> +                          "or dev_opp_list_lock protection");
> +
>         dev_opp = find_device_opp(dev);
>         if (IS_ERR(dev_opp)) {
>                 int r = PTR_ERR(dev_opp);
> @@ -267,6 +272,11 @@ 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);
>
> +       rcu_lockdep_assert(rcu_read_lock_held() ||
> +                               lockdep_is_held(&dev_opp_list_lock),
> +                          "dev_pm_opp_find_freq_exact() needs rcu_read_lock() "
> +                          "or dev_opp_list_lock protection");
> +
>         dev_opp = find_device_opp(dev);
>         if (IS_ERR(dev_opp)) {
>                 int r = PTR_ERR(dev_opp);
> @@ -313,6 +323,11 @@ 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);
>
> +       rcu_lockdep_assert(rcu_read_lock_held() ||
> +                               lockdep_is_held(&dev_opp_list_lock),
> +                          "dev_pm_opp_find_freq_ceil() needs rcu_read_lock() "
> +                          "or dev_opp_list_lock protection");
> +
>         if (!dev || !freq) {
>                 dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
>                 return ERR_PTR(-EINVAL);
> @@ -361,6 +376,11 @@ 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);
>
> +       rcu_lockdep_assert(rcu_read_lock_held() ||
> +                               lockdep_is_held(&dev_opp_list_lock),
> +                          "dev_pm_opp_find_freq_floor() needs rcu_read_lock() "
> +                          "or dev_opp_list_lock protection");
> +

To get rid of the redundancy a bit, what about something like:

#define opp_rcu_lockdep_assert()        \
        rcu_lockdep_assert(rcu_read_lock_held() || \
                                        lockdep_is_held(&dev_opp_list_lock), \
                                        "Missing rcu_read_lock() or
dev_opp_list_lock protection");
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diff mbox

Patch

diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index d24dd614a..852eebf 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -218,6 +218,11 @@  int dev_pm_opp_get_opp_count(struct device *dev)
 	struct dev_pm_opp *temp_opp;
 	int count = 0;
 
+	rcu_lockdep_assert(rcu_read_lock_held() ||
+				lockdep_is_held(&dev_opp_list_lock),
+			   "dev_pm_opp_get_opp_count() needs rcu_read_lock() "
+			   "or dev_opp_list_lock protection");
+
 	dev_opp = find_device_opp(dev);
 	if (IS_ERR(dev_opp)) {
 		int r = PTR_ERR(dev_opp);
@@ -267,6 +272,11 @@  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);
 
+	rcu_lockdep_assert(rcu_read_lock_held() ||
+				lockdep_is_held(&dev_opp_list_lock),
+			   "dev_pm_opp_find_freq_exact() needs rcu_read_lock() "
+			   "or dev_opp_list_lock protection");
+
 	dev_opp = find_device_opp(dev);
 	if (IS_ERR(dev_opp)) {
 		int r = PTR_ERR(dev_opp);
@@ -313,6 +323,11 @@  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);
 
+	rcu_lockdep_assert(rcu_read_lock_held() ||
+				lockdep_is_held(&dev_opp_list_lock),
+			   "dev_pm_opp_find_freq_ceil() needs rcu_read_lock() "
+			   "or dev_opp_list_lock protection");
+
 	if (!dev || !freq) {
 		dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
 		return ERR_PTR(-EINVAL);
@@ -361,6 +376,11 @@  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);
 
+	rcu_lockdep_assert(rcu_read_lock_held() ||
+				lockdep_is_held(&dev_opp_list_lock),
+			   "dev_pm_opp_find_freq_floor() needs rcu_read_lock() "
+			   "or dev_opp_list_lock protection");
+
 	if (!dev || !freq) {
 		dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
 		return ERR_PTR(-EINVAL);