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

Guenter Roeck
2024-02-22T15:24:59Z

On 2/22/24 06:58, Marek Behún wrote:
> 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

else after return is unnecessary.

> + return 0;
> +}
> +
> #endif