[PATCH 1/2] regulator: Fix useless O^2 complexity in suspend/resume

From: Marek Szyprowski
Date: Mon Sep 03 2018 - 10:49:54 EST


regulator_pm_ops with regulator_suspend and regulator_resume functions are
assigned to every regulator device registered in the system, so there is no
need to iterate over all again in them. Replace class_for_each_device()
construction with direct operation on the rdev embedded in the given
regulator device. This saves a lots of useless operations in suspend and
resume paths.

Fixes: f7efad10b5c4: regulator: add PM suspend and resume hooks
Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
---
drivers/regulator/core.c | 39 +++++++++++----------------------------
1 file changed, 11 insertions(+), 28 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index bb1324f93143..71ba040c7c5b 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -4455,19 +4455,6 @@ void regulator_unregister(struct regulator_dev *rdev)
EXPORT_SYMBOL_GPL(regulator_unregister);

#ifdef CONFIG_SUSPEND
-static int _regulator_suspend(struct device *dev, void *data)
-{
- struct regulator_dev *rdev = dev_to_rdev(dev);
- suspend_state_t *state = data;
- int ret;
-
- regulator_lock(rdev);
- ret = suspend_set_state(rdev, *state);
- regulator_unlock(rdev);
-
- return ret;
-}
-
/**
* regulator_suspend - prepare regulators for system wide suspend
* @state: system suspend state
@@ -4476,20 +4463,25 @@ static int _regulator_suspend(struct device *dev, void *data)
*/
static int regulator_suspend(struct device *dev)
{
+ struct regulator_dev *rdev = dev_to_rdev(dev);
suspend_state_t state = pm_suspend_target_state;
+ int ret;
+
+ regulator_lock(rdev);
+ ret = suspend_set_state(rdev, state);
+ regulator_unlock(rdev);

- return class_for_each_device(&regulator_class, NULL, &state,
- _regulator_suspend);
+ return ret;
}

-static int _regulator_resume(struct device *dev, void *data)
+static int regulator_resume(struct device *dev)
{
- int ret = 0;
+ suspend_state_t state = pm_suspend_target_state;
struct regulator_dev *rdev = dev_to_rdev(dev);
- suspend_state_t *state = data;
struct regulator_state *rstate;
+ int ret = 0;

- rstate = regulator_get_suspend_state(rdev, *state);
+ rstate = regulator_get_suspend_state(rdev, state);
if (rstate == NULL)
return 0;

@@ -4504,15 +4496,6 @@ static int _regulator_resume(struct device *dev, void *data)

return ret;
}
-
-static int regulator_resume(struct device *dev)
-{
- suspend_state_t state = pm_suspend_target_state;
-
- return class_for_each_device(&regulator_class, NULL, &state,
- _regulator_resume);
-}
-
#else /* !CONFIG_SUSPEND */

#define regulator_suspend NULL
--
2.17.1