linux-stable.git/drivers/devfreq/governor_userspace.c, branch linux-5.4.y

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

2023-01-18T10:41:52+00:00

[ Upstream commit 5fdded8448924e3631d466eea499b11606c43640 ]

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@vger.kernel.org # 5.10+
Reviewed-by: Chanwoo Choi 
Acked-by: MyungJoo Ham 
Signed-off-by: Kant Fan 
Signed-off-by: Chanwoo Choi 
Signed-off-by: Sasha Levin

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55+00:00

Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Enrico Weigelt 
Reviewed-by: Kate Stewart 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman

PM / devfreq: Don't adjust to user limits in governors

2018-10-02T01:16:41+00:00

Several governors use the user space limits df->min/max_freq to adjust
the target frequency. This is not necessary, since update_devfreq()
already takes care of this. Instead the governor can request the available
min/max frequency by setting the target frequency to DEVFREQ_MIN/MAX_FREQ
and let update_devfreq() take care of any adjustments.

Signed-off-by: Matthias Kaehlcke 
Reviewed-by: Brian Norris 
Reviewed-by: Chanwoo Choi 
Signed-off-by: MyungJoo Ham

PM / devfreq: Define the constant governor name

2017-10-26T08:08:40+00:00

Prior to that, the devfreq device uses the governor name when adding
the itself. In order to prevent the mistake used the wrong governor name,
this patch defines the governor name as a constant and then uses them
instead of using the string directly.

Signed-off-by: Chanwoo Choi 
Signed-off-by: MyungJoo Ham 
Cc: Kukjin Kim 
Cc: Krzysztof Kozlowski 
Cc: linux-samsung-soc@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org

PM / devfreq: constify attribute_group structures.

2017-07-06T01:17:24+00:00

attribute_groups are not supposed to change at runtime. All functions
working with attribute_groups provided by  work with const
attribute_group. So mark the non-const structs as const.

File size before:
   text	   data	    bss	    dec	    hex	filename
    621	    176	      0	    797	    31d	drivers/devfreq/governor_userspace.o

File size After adding 'const':
   text	   data	    bss	    dec	    hex	filename
   670	    144	      0	    814	    32e	drivers/devfreq/governor_userspace.o

Signed-off-by: Arvind Yadav 
Reviewed-by: Chanwoo Choi 
Signed-off-by: MyungJoo Ham

PM / devfreq: Fix the wrong description for userspace governor

2017-01-31T05:12:19+00:00

This patch fixes the wrong description of governor_userspace.c
and removes the unneeded blank line.

Signed-off-by: Chanwoo Choi 
Signed-off-by: MyungJoo Ham

PM / devfreq: Don't delete sysfs group twice

2017-01-31T05:12:18+00:00

The 'userspace' governor adds a sysfs entry, which is removed when
the governor is changed, or the devfreq device is released. However,
when the latter occurs via device_unregister(), device_del() is
called first, which removes the sysfs entries recursively and deletes
the kobject.

This means we get an Oops when the governor calls
sysfs_remove_group() on the deleted kobject. Fix this by only doing
the call when kobj *hasn't* been kobject_del()'d.

Note that we can't just remove the call to sysfs_remove_group()
entirely - it's needed for when the governor is changed to one which
doesn't need a sysfs entry.

Signed-off-by: Chris Diamand 
Reviewed-by: Chanwoo Choi 
Signed-off-by: MyungJoo Ham

PM / devfreq: governors: add GPL module license and allow module build

2012-11-20T09:46:23+00:00

Add GPL module license and remove the static build
restrictions for building governors. This allows governors now
to be loaded on a need basis and reloaded independently of kernel
build

Cc: Rajagopal Venkat 
Cc: MyungJoo Ham 
Cc: Kyungmin Park 
Cc: "Rafael J. Wysocki" 
Cc: Kevin Hilman 
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

Signed-off-by: Nishanth Menon 
Acked-by: MyungJoo Ham 
Signed-off-by: MyungJoo Ham

PM / devfreq: map devfreq drivers to governor using name

2012-11-20T09:46:22+00:00

Allow devfreq drivers to register a preferred governor name
and when the devfreq governor loads itself at a later point
required drivers are managed appropriately, at the time of
unload of a devfreq governor, stop managing those drivers
as well.

Since the governor structures do not need to be exposed
anymore, remove the definitions and make them static

NOTE: devfreq_list_lock is now used to protect governor
start and stop - as this allows us to protect governors and
devfreq with the proper dependencies as needed.

As part of this change, change the registration of exynos
bus driver to request for ondemand using the governor name.

Cc: Rajagopal Venkat 
Cc: MyungJoo Ham 
Cc: Kyungmin Park 
Cc: "Rafael J. Wysocki" 
Cc: Kevin Hilman 
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

Signed-off-by: Nishanth Menon 
[Merge conflict resolved by MyungJoo Ham]
Signed-off-by: MyungJoo Ham

PM / devfreq: register governors with devfreq framework

2012-11-20T09:46:22+00:00

With the new registration functions, governors can be now
registered with devfreq framework.

NOTE: generates 'discards qualifiers from pointer target type'
build warnings, which the next patche in this series fixes

Cc: Rajagopal Venkat 
Cc: MyungJoo Ham 
Cc: Kyungmin Park 
Cc: "Rafael J. Wysocki" 
Cc: Kevin Hilman 
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

Signed-off-by: Nishanth Menon 
Acked-by: MyungJoo Ham 
Signed-off-by: MyungJoo Ham