On 22. 10. 25. 16:21, Kant Fan wrote:
The member void *data in the structure devfreq can be overwrite by governor_userspace. For example:
- 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@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
drivers/devfreq/devfreq.c | 6 ++---- drivers/devfreq/governor_userspace.c | 12 ++++++------ include/linux/devfreq.h | 7 ++++--- 3 files changed, 12 insertions(+), 13 deletions(-)
(snip)
Applied it. Thanks.