linux-kernel - Re: [PATCH v2 1/2] hwmon: (pmbus/core) Add lock and unlock functions

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Date:   Sun, 16 Apr 2023 07:03:22 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Eddie James <eajames@...ux.ibm.com>
Cc:     linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org,
        jdelvare@...e.com
Subject: Re: [PATCH v2 1/2] hwmon: (pmbus/core) Add lock and unlock functions

On Wed, Apr 12, 2023 at 11:15:25AM -0500, Eddie James wrote:
> Debugfs operations may set the page number, which must be done
> atomically with the subsequent i2c operation. Lock the update_lock
> in the debugfs functions and provide a function for pmbus drivers
> to lock and unlock the update_lock.
> 
> Signed-off-by: Eddie James <eajames@...ux.ibm.com>

Applied.

Thanks,
Guenter

> ---
>  drivers/hwmon/pmbus/pmbus.h      |  2 ++
>  drivers/hwmon/pmbus/pmbus_core.c | 30 ++++++++++++++++++++++++++++++
>  2 files changed, 32 insertions(+)
> 
> diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
> index 11e84e141126..b0832a4c690d 100644
> --- a/drivers/hwmon/pmbus/pmbus.h
> +++ b/drivers/hwmon/pmbus/pmbus.h
> @@ -505,6 +505,8 @@ int pmbus_get_fan_rate_device(struct i2c_client *client, int page, int id,
>  			      enum pmbus_fan_mode mode);
>  int pmbus_get_fan_rate_cached(struct i2c_client *client, int page, int id,
>  			      enum pmbus_fan_mode mode);
> +int pmbus_lock_interruptible(struct i2c_client *client);
> +void pmbus_unlock(struct i2c_client *client);
>  int pmbus_update_fan(struct i2c_client *client, int page, int id,
>  		     u8 config, u8 mask, u16 command);
>  struct dentry *pmbus_get_debugfs_dir(struct i2c_client *client);
> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> index ca4510e4f918..04b4c65666fd 100644
> --- a/drivers/hwmon/pmbus/pmbus_core.c
> +++ b/drivers/hwmon/pmbus/pmbus_core.c
> @@ -3212,8 +3212,13 @@ static int pmbus_debugfs_get(void *data, u64 *val)
>  {
>  	int rc;
>  	struct pmbus_debugfs_entry *entry = data;
> +	struct pmbus_data *pdata = i2c_get_clientdata(entry->client);
>  
> +	rc = mutex_lock_interruptible(&pdata->update_lock);
> +	if (rc)
> +		return rc;
>  	rc = _pmbus_read_byte_data(entry->client, entry->page, entry->reg);
> +	mutex_unlock(&pdata->update_lock);
>  	if (rc < 0)
>  		return rc;
>  
> @@ -3230,7 +3235,11 @@ static int pmbus_debugfs_get_status(void *data, u64 *val)
>  	struct pmbus_debugfs_entry *entry = data;
>  	struct pmbus_data *pdata = i2c_get_clientdata(entry->client);
>  
> +	rc = mutex_lock_interruptible(&pdata->update_lock);
> +	if (rc)
> +		return rc;
>  	rc = pdata->read_status(entry->client, entry->page);
> +	mutex_unlock(&pdata->update_lock);
>  	if (rc < 0)
>  		return rc;
>  
> @@ -3246,10 +3255,15 @@ static ssize_t pmbus_debugfs_mfr_read(struct file *file, char __user *buf,
>  {
>  	int rc;
>  	struct pmbus_debugfs_entry *entry = file->private_data;
> +	struct pmbus_data *pdata = i2c_get_clientdata(entry->client);
>  	char data[I2C_SMBUS_BLOCK_MAX + 2] = { 0 };
>  
> +	rc = mutex_lock_interruptible(&pdata->update_lock);
> +	if (rc)
> +		return rc;
>  	rc = pmbus_read_block_data(entry->client, entry->page, entry->reg,
>  				   data);
> +	mutex_unlock(&pdata->update_lock);
>  	if (rc < 0)
>  		return rc;
>  
> @@ -3587,6 +3601,22 @@ struct dentry *pmbus_get_debugfs_dir(struct i2c_client *client)
>  }
>  EXPORT_SYMBOL_NS_GPL(pmbus_get_debugfs_dir, PMBUS);
>  
> +int pmbus_lock_interruptible(struct i2c_client *client)
> +{
> +	struct pmbus_data *data = i2c_get_clientdata(client);
> +
> +	return mutex_lock_interruptible(&data->update_lock);
> +}
> +EXPORT_SYMBOL_NS_GPL(pmbus_lock_interruptible, PMBUS);
> +
> +void pmbus_unlock(struct i2c_client *client)
> +{
> +	struct pmbus_data *data = i2c_get_clientdata(client);
> +
> +	mutex_unlock(&data->update_lock);
> +}
> +EXPORT_SYMBOL_NS_GPL(pmbus_unlock, PMBUS);
> +
>  static int __init pmbus_core_init(void)
>  {
>  	pmbus_debugfs_dir = debugfs_create_dir("pmbus", NULL);