This is a note to let you know that I've just added the patch titled PM/devfreq: governor: Add a private governor_data for governor to the 6.1-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: pm-devfreq-governor-add-a-private-governor_data-for-governor.patch and it can be found in the queue-6.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 5fdded8448924e3631d466eea499b11606c43640 Mon Sep 17 00:00:00 2001 From: Kant Fan <kant@xxxxxxxxxxxxxxxxx> Date: Tue, 25 Oct 2022 15:21:09 +0800 Subject: PM/devfreq: governor: Add a private governor_data for governor From: Kant Fan <kant@xxxxxxxxxxxxxxxxx> commit 5fdded8448924e3631d466eea499b11606c43640 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: ce26c5bb9569 ("PM / devfreq: Add basic governors") Cc: stable@xxxxxxxxxxxxxxx # 5.10+ Reviewed-by: Chanwoo Choi <cwchoi00@xxxxxxxxx> Acked-by: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx> Signed-off-by: Kant Fan <kant@xxxxxxxxxxxxxxxxx> Signed-off-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/devfreq/devfreq.c | 6 ++---- drivers/devfreq/governor_userspace.c | 12 ++++++------ include/linux/devfreq.h | 7 ++++--- 3 files changed, 12 insertions(+), 13 deletions(-) --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -776,8 +776,7 @@ static void remove_sysfs_files(struct de * @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, @@ -1011,8 +1010,7 @@ static void devm_devfreq_dev_release(str * @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 --- a/drivers/devfreq/governor_userspace.c +++ b/drivers/devfreq/governor_userspace.c @@ -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 dev 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 devi 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 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 devfre 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, --- a/include/linux/devfreq.h +++ b/include/linux/devfreq.h @@ -152,8 +152,8 @@ struct devfreq_stats { * @max_state: count of entry present in the frequency table. * @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 @@ -193,7 +193,8 @@ 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; Patches currently in stable-queue which might be from kant@xxxxxxxxxxxxxxxxx are queue-6.1/pm-devfreq-governor-add-a-private-governor_data-for-governor.patch