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PM/devfreq: governor: Add a private governor_data for governor

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commit 5fdded8448 upstream.

The member void *data in the structure devfreq can be overwrite
by governor_userspace. For example:
1. The device driver assigned the devfreq governor to simple_ondemand
by the function devfreq_add_device() and init the devfreq member
void *data to a pointer of a static structure devfreq_simple_ondemand_data
by the function devfreq_add_device().
2. The user changed the devfreq governor to userspace by the command
"echo userspace > /sys/class/devfreq/.../governor".
3. The governor userspace alloced a dynamic memory for the struct
userspace_data and assigend the member void *data of devfreq to
this memory by the function userspace_init().
4. The user changed the devfreq governor back to simple_ondemand
by the command "echo simple_ondemand > /sys/class/devfreq/.../governor".
5. The governor userspace exited and assigned the member void *data
in the structure devfreq to NULL by the function userspace_exit().
6. The governor simple_ondemand fetched the static information of
devfreq_simple_ondemand_data in the function
devfreq_simple_ondemand_func() but the member void *data of devfreq was
assigned to NULL by the function userspace_exit().
7. The information of upthreshold and downdifferential is lost
and the governor simple_ondemand can't work correctly.

The member void *data in the structure devfreq is designed for
a static pointer used in a governor and inited by the function
devfreq_add_device(). This patch add an element named governor_data
in the devfreq structure which can be used by a governor(E.g userspace)
who want to assign a private data to do some private things.

Fixes: ce26c5bb95 ("PM / devfreq: Add basic governors")
Cc: stable@vger.kernel.org # 5.10+
Reviewed-by: Chanwoo Choi <cwchoi00@gmail.com>
Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kant Fan <kant@allwinnertech.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Kant Fan 2022-10-25 15:21:09 +08:00 • committed by Justin Hammond
parent b2ce28f16b
commit 5e012637fa
3 changed files with 12 additions and 13 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

6
drivers/devfreq/devfreq.c
View file

@ -775,8 +775,7 @@ static void remove_sysfs_files(struct devfreq *devfreq,
* @dev: the device to add devfreq feature.
* @profile: device-specific profile to run devfreq.
* @governor_name: name of the policy to choose frequency.
* @data: private data for the governor. The devfreq framework does not
* touch this value.
* @data: devfreq driver pass to governors, governor should not change it.
*/
struct devfreq *devfreq_add_device(struct device *dev,
struct devfreq_dev_profile *profile,
@ -1003,8 +1002,7 @@ static void devm_devfreq_dev_release(struct device *dev, void *res)
* @dev: the device to add devfreq feature.
* @profile: device-specific profile to run devfreq.
* @governor_name: name of the policy to choose frequency.
* @data: private data for the governor. The devfreq framework does not
* touch this value.
* @data: devfreq driver pass to governors, governor should not change it.
*
* This function manages automatically the memory of devfreq device using device
* resource management and simplify the free operation for memory of devfreq

12
drivers/devfreq/governor_userspace.c
View file

@ -21,7 +21,7 @@ struct userspace_data {
static int devfreq_userspace_func(struct devfreq *df, unsigned long *freq)
{
struct userspace_data *data = df->data;
struct userspace_data *data = df->governor_data;
if (data->valid)
*freq = data->user_frequency;
@ -40,7 +40,7 @@ static ssize_t set_freq_store(struct device *dev, struct device_attribute *attr,
int err = 0;
mutex_lock(&devfreq->lock);
data = devfreq->data;
data = devfreq->governor_data;
sscanf(buf, "%lu", &wanted);
data->user_frequency = wanted;
@ -60,7 +60,7 @@ static ssize_t set_freq_show(struct device *dev,
int err = 0;
mutex_lock(&devfreq->lock);
data = devfreq->data;
data = devfreq->governor_data;
if (data->valid)
err = sprintf(buf, "%lu\n", data->user_frequency);
@ -91,7 +91,7 @@ static int userspace_init(struct devfreq *devfreq)
goto out;
}
data->valid = false;
devfreq->data = data;
devfreq->governor_data = data;
err = sysfs_create_group(&devfreq->dev.kobj, &dev_attr_group);
out:
@ -107,8 +107,8 @@ static void userspace_exit(struct devfreq *devfreq)
if (devfreq->dev.kobj.sd)
sysfs_remove_group(&devfreq->dev.kobj, &dev_attr_group);
kfree(devfreq->data);
devfreq->data = NULL;
kfree(devfreq->governor_data);
devfreq->governor_data = NULL;
}
static int devfreq_userspace_handler(struct devfreq *devfreq,

7
include/linux/devfreq.h
View file

@ -149,8 +149,8 @@ struct devfreq_stats {
* @work: delayed work for load monitoring.
* @previous_freq: previously configured frequency value.
* @last_status: devfreq user device info, performance statistics
* @data: Private data of the governor. The devfreq framework does not
* touch this.
* @data: devfreq driver pass to governors, governor should not change it.
* @governor_data: private data for governors, devfreq core doesn't touch it.
* @user_min_freq_req: PM QoS minimum frequency request from user (via sysfs)
* @user_max_freq_req: PM QoS maximum frequency request from user (via sysfs)
* @scaling_min_freq: Limit minimum frequency requested by OPP interface
@ -187,7 +187,8 @@ struct devfreq {
unsigned long previous_freq;
struct devfreq_dev_status last_status;
void *data; /* private data for governors */
void *data;
void *governor_data;
struct dev_pm_qos_request user_min_freq_req;
struct dev_pm_qos_request user_max_freq_req;