[PATCH 1/2] devm-helpers: Add resource managed version of mutex init

Marek Behún
2024-02-22T14:58:48Z

A few drivers are doing resource-managed mutex initialization by
implementing ad-hoc one-liner mutex dropping functions and using them
with devm_add_action_or_reset(). Help drivers avoid these repeated
one-liners by adding managed version of mutex initialization.

Use the new function devm_mutex_init() in the following drivers:
drivers/gpio/gpio-pisosr.c
drivers/gpio/gpio-sim.c
drivers/gpu/drm/xe/xe_hwmon.c
drivers/hwmon/nzxt-smart2.c
drivers/leds/leds-is31fl319x.c
drivers/power/supply/mt6370-charger.c
drivers/power/supply/rt9467-charger.c

Signed-off-by: Marek Behún <kabel@kernel.org>
---
drivers/gpio/gpio-pisosr.c | 9 ++-----
drivers/gpio/gpio-sim.c | 12 ++--------
drivers/gpu/drm/xe/xe_hwmon.c | 11 ++-------
drivers/hwmon/nzxt-smart2.c | 9 ++-----
drivers/leds/leds-is31fl319x.c | 9 ++-----
drivers/power/supply/mt6370-charger.c | 11 +--------
drivers/power/supply/rt9467-charger.c | 34 ++++-----------------------
include/linux/devm-helpers.h | 32 +++++++++++++++++++++++++
8 files changed, 47 insertions(+), 80 deletions(-)

diff --git a/drivers/gpio/gpio-pisosr.c b/drivers/gpio/gpio-pisosr.c
index e3013e778e15..dddbf37e855f 100644
--- a/drivers/gpio/gpio-pisosr.c
+++ b/drivers/gpio/gpio-pisosr.c
@@ -7,6 +7,7 @@
#include <linux/bitmap.h>
#include <linux/bitops.h>
#include <linux/delay.h>
+#include <linux/devm-helpers.h>
#include <linux/gpio/consumer.h>
#include <linux/gpio/driver.h>
#include <linux/module.h>
@@ -116,11 +117,6 @@ static const struct gpio_chip template_chip = {
.can_sleep = true,
};

-static void pisosr_mutex_destroy(void *lock)
-{
- mutex_destroy(lock);
-}
-
static int pisosr_gpio_probe(struct spi_device *spi)
{
struct device *dev = &spi->dev;
@@ -147,8 +143,7 @@ static int pisosr_gpio_probe(struct spi_device *spi)
return dev_err_probe(dev, PTR_ERR(gpio->load_gpio),
"Unable to allocate load GPIO\n");

- mutex_init(&gpio->lock);
- ret = devm_add_action_or_reset(dev, pisosr_mutex_destroy, &gpio->lock);
+ ret = devm_mutex_init(dev, &gpio->lock);
if (ret)
return ret;

diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c
index c4106e37e6db..fcfcaa4efe70 100644
--- a/drivers/gpio/gpio-sim.c
+++ b/drivers/gpio/gpio-sim.c
@@ -12,6 +12,7 @@
#include <linux/completion.h>
#include <linux/configfs.h>
#include <linux/device.h>
+#include <linux/devm-helpers.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/gpio/driver.h>
@@ -307,13 +308,6 @@ static ssize_t gpio_sim_sysfs_pull_store(struct device *dev,
return len;
}

-static void gpio_sim_mutex_destroy(void *data)
-{
- struct mutex *lock = data;
-
- mutex_destroy(lock);
-}
-
static void gpio_sim_put_device(void *data)
{
struct device *dev = data;
@@ -457,9 +451,7 @@ static int gpio_sim_add_bank(struct fwnode_handle *swnode, struct device *dev)
if (ret)
return ret;

- mutex_init(&chip->lock);
- ret = devm_add_action_or_reset(dev, gpio_sim_mutex_destroy,
- &chip->lock);
+ ret = devm_mutex_init(dev, &chip->lock);
if (ret)
return ret;

diff --git a/drivers/gpu/drm/xe/xe_hwmon.c b/drivers/gpu/drm/xe/xe_hwmon.c
index 174ed2185481..bb88ae1c196c 100644
--- a/drivers/gpu/drm/xe/xe_hwmon.c
+++ b/drivers/gpu/drm/xe/xe_hwmon.c
@@ -3,6 +3,7 @@
* Copyright © 2023 Intel Corporation
*/

+#include <linux/devm-helpers.h>
#include <linux/hwmon-sysfs.h>
#include <linux/hwmon.h>
#include <linux/types.h>
@@ -729,13 +730,6 @@ xe_hwmon_get_preregistration_info(struct xe_device *xe)
xe_hwmon_energy_get(hwmon, &energy);
}

-static void xe_hwmon_mutex_destroy(void *arg)
-{
- struct xe_hwmon *hwmon = arg;
-
- mutex_destroy(&hwmon->hwmon_lock);
-}
-
void xe_hwmon_register(struct xe_device *xe)
{
struct device *dev = xe->drm.dev;
@@ -751,8 +745,7 @@ void xe_hwmon_register(struct xe_device *xe)

xe->hwmon = hwmon;

- mutex_init(&hwmon->hwmon_lock);
- if (devm_add_action_or_reset(dev, xe_hwmon_mutex_destroy, hwmon))
+ if (devm_mutex_init(dev, &hwmon->hwmon_lock))
return;

/* primary GT to access device level properties */
diff --git a/drivers/hwmon/nzxt-smart2.c b/drivers/hwmon/nzxt-smart2.c
index 7aa586eb74be..00bc89607673 100644
--- a/drivers/hwmon/nzxt-smart2.c
+++ b/drivers/hwmon/nzxt-smart2.c
@@ -5,6 +5,7 @@
* Copyright (c) 2021 Aleksandr Mezin
*/

+#include <linux/devm-helpers.h>
#include <linux/hid.h>
#include <linux/hwmon.h>
#include <linux/math.h>
@@ -721,11 +722,6 @@ static int __maybe_unused nzxt_smart2_hid_reset_resume(struct hid_device *hdev)
return init_device(drvdata, drvdata->update_interval);
}

-static void mutex_fini(void *lock)
-{
- mutex_destroy(lock);
-}
-
static int nzxt_smart2_hid_probe(struct hid_device *hdev,
const struct hid_device_id *id)
{
@@ -741,8 +737,7 @@ static int nzxt_smart2_hid_probe(struct hid_device *hdev,

init_waitqueue_head(&drvdata->wq);

- mutex_init(&drvdata->mutex);
- ret = devm_add_action_or_reset(&hdev->dev, mutex_fini, &drvdata->mutex);
+ ret = devm_mutex_init(&hdev->dev, &drvdata->mutex);
if (ret)
return ret;

diff --git a/drivers/leds/leds-is31fl319x.c b/drivers/leds/leds-is31fl319x.c
index 66c65741202e..e9d7cf6a386c 100644
--- a/drivers/leds/leds-is31fl319x.c
+++ b/drivers/leds/leds-is31fl319x.c
@@ -8,6 +8,7 @@
* effect LEDs.
*/

+#include <linux/devm-helpers.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/leds.h>
@@ -495,11 +496,6 @@ static inline int is31fl3196_db_to_gain(u32 dezibel)
return dezibel / IS31FL3196_AUDIO_GAIN_DB_STEP;
}

-static void is31f1319x_mutex_destroy(void *lock)
-{
- mutex_destroy(lock);
-}
-
static int is31fl319x_probe(struct i2c_client *client)
{
struct is31fl319x_chip *is31;
@@ -515,8 +511,7 @@ static int is31fl319x_probe(struct i2c_client *client)
if (!is31)
return -ENOMEM;

- mutex_init(&is31->lock);
- err = devm_add_action_or_reset(dev, is31f1319x_mutex_destroy, &is31->lock);
+ err = devm_mutex_init(dev, &is31->lock);
if (err)
return err;

diff --git a/drivers/power/supply/mt6370-charger.c b/drivers/power/supply/mt6370-charger.c
index e24fce087d80..fa0517d0352d 100644
--- a/drivers/power/supply/mt6370-charger.c
+++ b/drivers/power/supply/mt6370-charger.c
@@ -766,13 +766,6 @@ static int mt6370_chg_init_psy(struct mt6370_priv *priv)
return PTR_ERR_OR_ZERO(priv->psy);
}

-static void mt6370_chg_destroy_attach_lock(void *data)
-{
- struct mutex *attach_lock = data;
-
- mutex_destroy(attach_lock);
-}
-
static void mt6370_chg_destroy_wq(void *data)
{
struct workqueue_struct *wq = data;
@@ -900,9 +893,7 @@ static int mt6370_chg_probe(struct platform_device *pdev)
if (ret)
return dev_err_probe(dev, ret, "Failed to init psy\n");

- mutex_init(&priv->attach_lock);
- ret = devm_add_action_or_reset(dev, mt6370_chg_destroy_attach_lock,
- &priv->attach_lock);
+ ret = devm_mutex_init(dev, &priv->attach_lock);
if (ret)
return dev_err_probe(dev, ret, "Failed to init attach lock\n");

diff --git a/drivers/power/supply/rt9467-charger.c b/drivers/power/supply/rt9467-charger.c
index fdfdc83ab045..84f07c22077f 100644
--- a/drivers/power/supply/rt9467-charger.c
+++ b/drivers/power/supply/rt9467-charger.c
@@ -10,6 +10,7 @@
#include <linux/bitfield.h>
#include <linux/completion.h>
#include <linux/delay.h>
+#include <linux/devm-helpers.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
@@ -1149,27 +1150,6 @@ static int rt9467_reset_chip(struct rt9467_chg_data *data)
return regmap_field_write(data->rm_field[F_RST], 1);
}

-static void rt9467_chg_destroy_adc_lock(void *data)
-{
- struct mutex *adc_lock = data;
-
- mutex_destroy(adc_lock);
-}
-
-static void rt9467_chg_destroy_attach_lock(void *data)
-{
- struct mutex *attach_lock = data;
-
- mutex_destroy(attach_lock);
-}
-
-static void rt9467_chg_destroy_ichg_ieoc_lock(void *data)
-{
- struct mutex *ichg_ieoc_lock = data;
-
- mutex_destroy(ichg_ieoc_lock);
-}
-
static void rt9467_chg_complete_aicl_done(void *data)
{
struct completion *aicl_done = data;
@@ -1222,21 +1202,15 @@ static int rt9467_charger_probe(struct i2c_client *i2c)
if (ret)
return dev_err_probe(dev, ret, "Failed to add irq chip\n");

- mutex_init(&data->adc_lock);
- ret = devm_add_action_or_reset(dev, rt9467_chg_destroy_adc_lock,
- &data->adc_lock);
+ ret = devm_mutex_init(dev, &data->adc_lock);
if (ret)
return dev_err_probe(dev, ret, "Failed to init ADC lock\n");

- mutex_init(&data->attach_lock);
- ret = devm_add_action_or_reset(dev, rt9467_chg_destroy_attach_lock,
- &data->attach_lock);
+ ret = devm_mutex_init(dev, &data->attach_lock);
if (ret)
return dev_err_probe(dev, ret, "Failed to init attach lock\n");

- mutex_init(&data->ichg_ieoc_lock);
- ret = devm_add_action_or_reset(dev, rt9467_chg_destroy_ichg_ieoc_lock,
- &data->ichg_ieoc_lock);
+ ret = devm_mutex_init(dev, &data->ichg_ieoc_lock);
if (ret)
return dev_err_probe(dev, ret, "Failed to init ICHG/IEOC lock\n");

diff --git a/include/linux/devm-helpers.h b/include/linux/devm-helpers.h
index 74891802200d..70640fb96117 100644
--- a/include/linux/devm-helpers.h
+++ b/include/linux/devm-helpers.h
@@ -24,6 +24,8 @@
*/

#include <linux/device.h>
+#include <linux/kconfig.h>
+#include <linux/mutex.h>
#include <linux/workqueue.h>

static inline void devm_delayed_work_drop(void *res)
@@ -76,4 +78,34 @@ static inline int devm_work_autocancel(struct device *dev,
return devm_add_action(dev, devm_work_drop, w);
}

+static inline void devm_mutex_drop(void *res)
+{
+ mutex_destroy(res);
+}
+
+/**
+ * devm_mutex_init - Resource managed mutex initialization
+ * @dev: Device which lifetime mutex is bound to
+ * @lock: Mutex to be initialized (and automatically destroyed)
+ *
+ * Initialize mutex which is automatically destroyed when driver is detached.
+ * A few drivers initialize mutexes which they want destroyed before driver is
+ * detached, for debugging purposes.
+ * devm_mutex_init() can be used to omit the explicit mutex_destroy() call when
+ * driver is detached.
+ */
+static inline int devm_mutex_init(struct device *dev, struct mutex *lock)
+{
+ mutex_init(lock);
+
+ /*
+ * mutex_destroy() is an empty function if CONFIG_DEBUG_MUTEXES is
+ * disabled. No need to allocate an action in that case.
+ */
+ if (IS_ENABLED(CONFIG_DEBUG_MUTEXES))
+ return devm_add_action_or_reset(dev, devm_mutex_drop, lock);
+ else
+ return 0;
+}
+
#endif
--
2.43.0