2023-12-05 12:28:07

by Rafael J. Wysocki

[permalink] [raw]
Subject: [PATCH v4 0/2] thermal: sysfs: Simplifications of trip point attribute callbacks

Hi,

This is the 4th iteration of

https://lore.kernel.org/linux-pm/5754079.DvuYhMxLoT@kreacher/

The difference between it and the 3rd iteration:

https://lore.kernel.org/linux-pm/12338384.O9o76ZdvQC@kreacher/

is the lack of trip ID validation checks in the _store and _show
callback routines modified by it.

Please refer to the individual patch changelogs for details.

Thanks!





2023-12-05 12:28:17

by Rafael J. Wysocki

[permalink] [raw]
Subject: [PATCH v4 1/2] thermal: sysfs: Rework the handling of trip point updates

From: Rafael J. Wysocki <[email protected]>

Both trip_point_temp_store() and trip_point_hyst_store() use
thermal_zone_set_trip() to update a given trip point, but none of them
actually needs to change more than one field in struct thermal_trip
representing it. However, each of them effectively calls
__thermal_zone_get_trip() twice in a row for the same trip index value,
once directly and once via thermal_zone_set_trip(), which is not
particularly efficient, and the way in which thermal_zone_set_trip()
carries out the update is not particularly straightforward.

Moreover, input processing need not be done under the thermal zone lock
in any of these functions.

Rework trip_point_temp_store() and trip_point_hyst_store() to address
the above, move the part of thermal_zone_set_trip() that is still
useful to a new function called thermal_zone_trip_updated() and drop
the rest of it.

While at it, make trip_point_hyst_store() reject negative hysteresis
values.

Signed-off-by: Rafael J. Wysocki <[email protected]>
---

v3 -> v4: Don't check trip_id against boundaries in trip_point_temp_store() and
trip_point_hyst_store() (Daniel).

v2 -> v3: No changes

v1 -> v2: Still check device_is_registered() under the zone lock

---
drivers/thermal/thermal_core.h | 2 +
drivers/thermal/thermal_sysfs.c | 52 +++++++++++++++++++++++++++-------------
drivers/thermal/thermal_trip.c | 45 ++++++----------------------------
include/linux/thermal.h | 4 ---
4 files changed, 47 insertions(+), 56 deletions(-)

Index: linux-pm/drivers/thermal/thermal_sysfs.c
===================================================================
--- linux-pm.orig/drivers/thermal/thermal_sysfs.c
+++ linux-pm/drivers/thermal/thermal_sysfs.c
@@ -120,8 +120,13 @@ trip_point_temp_store(struct device *dev
const char *buf, size_t count)
{
struct thermal_zone_device *tz = to_thermal_zone(dev);
- struct thermal_trip trip;
+ struct thermal_trip *trip;
int trip_id, ret;
+ int temp;
+
+ ret = kstrtoint(buf, 10, &temp);
+ if (ret)
+ return -EINVAL;

if (sscanf(attr->attr.name, "trip_point_%d_temp", &trip_id) != 1)
return -EINVAL;
@@ -133,15 +138,20 @@ trip_point_temp_store(struct device *dev
goto unlock;
}

- ret = __thermal_zone_get_trip(tz, trip_id, &trip);
- if (ret)
- goto unlock;
+ trip = &tz->trips[trip_id];

- ret = kstrtoint(buf, 10, &trip.temperature);
- if (ret)
- goto unlock;
+ if (temp != trip->temperature) {
+ if (tz->ops->set_trip_temp) {
+ ret = tz->ops->set_trip_temp(tz, trip_id, temp);
+ if (ret)
+ goto unlock;
+ }
+
+ trip->temperature = temp;
+
+ thermal_zone_trip_updated(tz, trip);
+ }

- ret = thermal_zone_set_trip(tz, trip_id, &trip);
unlock:
mutex_unlock(&tz->lock);

@@ -179,8 +189,13 @@ trip_point_hyst_store(struct device *dev
const char *buf, size_t count)
{
struct thermal_zone_device *tz = to_thermal_zone(dev);
- struct thermal_trip trip;
+ struct thermal_trip *trip;
int trip_id, ret;
+ int hyst;
+
+ ret = kstrtoint(buf, 10, &hyst);
+ if (ret || hyst < 0)
+ return -EINVAL;

if (sscanf(attr->attr.name, "trip_point_%d_hyst", &trip_id) != 1)
return -EINVAL;
@@ -192,15 +207,20 @@ trip_point_hyst_store(struct device *dev
goto unlock;
}

- ret = __thermal_zone_get_trip(tz, trip_id, &trip);
- if (ret)
- goto unlock;
+ trip = &tz->trips[trip_id];

- ret = kstrtoint(buf, 10, &trip.hysteresis);
- if (ret)
- goto unlock;
+ if (hyst != trip->hysteresis) {
+ if (tz->ops->set_trip_hyst) {
+ ret = tz->ops->set_trip_hyst(tz, trip_id, hyst);
+ if (ret)
+ goto unlock;
+ }
+
+ trip->hysteresis = hyst;
+
+ thermal_zone_trip_updated(tz, trip);
+ }

- ret = thermal_zone_set_trip(tz, trip_id, &trip);
unlock:
mutex_unlock(&tz->lock);

Index: linux-pm/drivers/thermal/thermal_core.h
===================================================================
--- linux-pm.orig/drivers/thermal/thermal_core.h
+++ linux-pm/drivers/thermal/thermal_core.h
@@ -124,6 +124,8 @@ int __thermal_zone_get_trip(struct therm
struct thermal_trip *trip);
int thermal_zone_trip_id(struct thermal_zone_device *tz,
const struct thermal_trip *trip);
+void thermal_zone_trip_updated(struct thermal_zone_device *tz,
+ const struct thermal_trip *trip);
int __thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp);

/* sysfs I/F */
Index: linux-pm/drivers/thermal/thermal_trip.c
===================================================================
--- linux-pm.orig/drivers/thermal/thermal_trip.c
+++ linux-pm/drivers/thermal/thermal_trip.c
@@ -147,42 +147,6 @@ int thermal_zone_get_trip(struct thermal
}
EXPORT_SYMBOL_GPL(thermal_zone_get_trip);

-int thermal_zone_set_trip(struct thermal_zone_device *tz, int trip_id,
- const struct thermal_trip *trip)
-{
- struct thermal_trip t;
- int ret;
-
- ret = __thermal_zone_get_trip(tz, trip_id, &t);
- if (ret)
- return ret;
-
- if (t.type != trip->type)
- return -EINVAL;
-
- if (t.temperature != trip->temperature && tz->ops->set_trip_temp) {
- ret = tz->ops->set_trip_temp(tz, trip_id, trip->temperature);
- if (ret)
- return ret;
- }
-
- if (t.hysteresis != trip->hysteresis && tz->ops->set_trip_hyst) {
- ret = tz->ops->set_trip_hyst(tz, trip_id, trip->hysteresis);
- if (ret)
- return ret;
- }
-
- if (tz->trips && (t.temperature != trip->temperature || t.hysteresis != trip->hysteresis))
- tz->trips[trip_id] = *trip;
-
- thermal_notify_tz_trip_change(tz->id, trip_id, trip->type,
- trip->temperature, trip->hysteresis);
-
- __thermal_zone_device_update(tz, THERMAL_TRIP_CHANGED);
-
- return 0;
-}
-
int thermal_zone_trip_id(struct thermal_zone_device *tz,
const struct thermal_trip *trip)
{
@@ -192,3 +156,12 @@ int thermal_zone_trip_id(struct thermal_
*/
return trip - tz->trips;
}
+
+void thermal_zone_trip_updated(struct thermal_zone_device *tz,
+ const struct thermal_trip *trip)
+{
+ thermal_notify_tz_trip_change(tz->id, thermal_zone_trip_id(tz, trip),
+ trip->type, trip->temperature,
+ trip->hysteresis);
+ __thermal_zone_device_update(tz, THERMAL_TRIP_CHANGED);
+}
Index: linux-pm/include/linux/thermal.h
===================================================================
--- linux-pm.orig/include/linux/thermal.h
+++ linux-pm/include/linux/thermal.h
@@ -282,10 +282,6 @@ int __thermal_zone_get_trip(struct therm
struct thermal_trip *trip);
int thermal_zone_get_trip(struct thermal_zone_device *tz, int trip_id,
struct thermal_trip *trip);
-
-int thermal_zone_set_trip(struct thermal_zone_device *tz, int trip_id,
- const struct thermal_trip *trip);
-
int for_each_thermal_trip(struct thermal_zone_device *tz,
int (*cb)(struct thermal_trip *, void *),
void *data);



2023-12-05 12:28:23

by Rafael J. Wysocki

[permalink] [raw]
Subject: [PATCH v4 2/2] thermal: sysfs: Rework the reading of trip point attributes

From: Rafael J. Wysocki <[email protected]>

Rework the _show() callback functions for the trip point temperature,
hysteresis and type attributes to avoid copying the values of struct
thermal_trip fields that they do not use and make them carry out the
same validation checks as the corresponding _store() callback functions.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <[email protected]>
---

v3 -> v4: Don't check trip_id against boundaries in the _show routines
for trip type, temperature and hysteresis (Daniel).

v2 -> v3: Drop a redundant 'ret' check at the end of trip_point_hyst_show.

v1 -> v2: Do not drop thermal zone locking from the _store() callback functions.

---
drivers/thermal/thermal_sysfs.c | 52 +++++++++++++++++++---------------------
1 file changed, 25 insertions(+), 27 deletions(-)

Index: linux-pm/drivers/thermal/thermal_sysfs.c
===================================================================
--- linux-pm.orig/drivers/thermal/thermal_sysfs.c
+++ linux-pm/drivers/thermal/thermal_sysfs.c
@@ -83,25 +83,24 @@ trip_point_type_show(struct device *dev,
char *buf)
{
struct thermal_zone_device *tz = to_thermal_zone(dev);
- struct thermal_trip trip;
- int trip_id, result;
+ enum thermal_trip_type type;
+ int trip_id;

if (sscanf(attr->attr.name, "trip_point_%d_type", &trip_id) != 1)
return -EINVAL;

mutex_lock(&tz->lock);

- if (device_is_registered(dev))
- result = __thermal_zone_get_trip(tz, trip_id, &trip);
- else
- result = -ENODEV;
+ if (!device_is_registered(dev)) {
+ mutex_unlock(&tz->lock);
+ return -ENODEV;
+ }

- mutex_unlock(&tz->lock);
+ type = tz->trips[trip_id].type;

- if (result)
- return result;
+ mutex_unlock(&tz->lock);

- switch (trip.type) {
+ switch (type) {
case THERMAL_TRIP_CRITICAL:
return sprintf(buf, "critical\n");
case THERMAL_TRIP_HOT:
@@ -163,25 +162,23 @@ trip_point_temp_show(struct device *dev,
char *buf)
{
struct thermal_zone_device *tz = to_thermal_zone(dev);
- struct thermal_trip trip;
- int trip_id, ret;
+ int trip_id, temp;

if (sscanf(attr->attr.name, "trip_point_%d_temp", &trip_id) != 1)
return -EINVAL;

mutex_lock(&tz->lock);

- if (device_is_registered(dev))
- ret = __thermal_zone_get_trip(tz, trip_id, &trip);
- else
- ret = -ENODEV;
+ if (!device_is_registered(dev)) {
+ mutex_unlock(&tz->lock);
+ return -ENODEV;
+ }

- mutex_unlock(&tz->lock);
+ temp = tz->trips[trip_id].temperature;

- if (ret)
- return ret;
+ mutex_unlock(&tz->lock);

- return sprintf(buf, "%d\n", trip.temperature);
+ return sprintf(buf, "%d\n", temp);
}

static ssize_t
@@ -232,22 +229,23 @@ trip_point_hyst_show(struct device *dev,
char *buf)
{
struct thermal_zone_device *tz = to_thermal_zone(dev);
- struct thermal_trip trip;
- int trip_id, ret;
+ int trip_id, hyst;

if (sscanf(attr->attr.name, "trip_point_%d_hyst", &trip_id) != 1)
return -EINVAL;

mutex_lock(&tz->lock);

- if (device_is_registered(dev))
- ret = __thermal_zone_get_trip(tz, trip_id, &trip);
- else
- ret = -ENODEV;
+ if (!device_is_registered(dev)) {
+ mutex_unlock(&tz->lock);
+ return -ENODEV;
+ }
+
+ hyst = tz->trips[trip_id].hysteresis;

mutex_unlock(&tz->lock);

- return ret ? ret : sprintf(buf, "%d\n", trip.hysteresis);
+ return sprintf(buf, "%d\n", hyst);
}

static ssize_t



2023-12-06 11:33:14

by Daniel Lezcano

[permalink] [raw]
Subject: Re: [PATCH v4 1/2] thermal: sysfs: Rework the handling of trip point updates

On 05/12/2023 13:24, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <[email protected]>
>
> Both trip_point_temp_store() and trip_point_hyst_store() use
> thermal_zone_set_trip() to update a given trip point, but none of them
> actually needs to change more than one field in struct thermal_trip
> representing it. However, each of them effectively calls
> __thermal_zone_get_trip() twice in a row for the same trip index value,
> once directly and once via thermal_zone_set_trip(), which is not
> particularly efficient, and the way in which thermal_zone_set_trip()
> carries out the update is not particularly straightforward.
>
> Moreover, input processing need not be done under the thermal zone lock
> in any of these functions.
>
> Rework trip_point_temp_store() and trip_point_hyst_store() to address
> the above, move the part of thermal_zone_set_trip() that is still
> useful to a new function called thermal_zone_trip_updated() and drop
> the rest of it.
>
> While at it, make trip_point_hyst_store() reject negative hysteresis
> values.
>
> Signed-off-by: Rafael J. Wysocki <[email protected]>
> ---

Reviewed-by: Daniel Lezcano <[email protected]>





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2023-12-06 11:35:55

by Daniel Lezcano

[permalink] [raw]
Subject: Re: [PATCH v4 2/2] thermal: sysfs: Rework the reading of trip point attributes

On 05/12/2023 13:26, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <[email protected]>
>
> Rework the _show() callback functions for the trip point temperature,
> hysteresis and type attributes to avoid copying the values of struct
> thermal_trip fields that they do not use and make them carry out the
> same validation checks as the corresponding _store() callback functions.
>
> No intentional functional impact.
>
> Signed-off-by: Rafael J. Wysocki <[email protected]>
> ---
>
> v3 -> v4: Don't check trip_id against boundaries in the _show routines
> for trip type, temperature and hysteresis (Daniel).
>
> v2 -> v3: Drop a redundant 'ret' check at the end of trip_point_hyst_show.
>
> v1 -> v2: Do not drop thermal zone locking from the _store() callback functions.
>
> ---

Reviewed-by: Daniel Lezcano <[email protected]>

--
<http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs

Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog