[PATCH v2 3/3] thermal: Make THERMAL_HWMON implementation fullyinternal

From: Jean Delvare
Date: Tue Apr 26 2011 - 11:04:18 EST


THERMAL_HWMON is implemented inside the thermal_sys driver and has no
effect on drivers implementing thermal zones, so they shouldn't see
anything related to it in <linux/thermal.h>. Making the THERMAL_HWMON
implementation fully internal has two advantages beyond the cleaner
design:
* This avoids rebuilding all thermal drivers if the THERMAL_HWMON
implementation changes, or if CONFIG_THERMAL_HWMON gets enabled or
disabled.
* This avoids breaking the thermal kABI in these cases too, which
should make distributions happy.

The only drawback I can see is slightly higher memory fragmentation,
as the number of kzalloc() calls will increase by one per thermal zone.
But I doubt it will be a problem in practice, as I've never seen a
system with more than two thermal zones.

Signed-off-by: Jean Delvare <khali@xxxxxxxxxxxx>
Cc: Rene Herman <rene.herman@xxxxxxxxx>
Cc: Len Brown <len.brown@xxxxxxxxx>
Cc: Guenter Roeck <guenter.roeck@xxxxxxxxxxxx>
---
* If memory fragmentation is really a concern to anyone, it would be
possible to save one kalloc for the first temperature input of each
zone type, as the price of slightly more complex code.

* Removal code path is untested, as I have never been able to unload
the thermal_sys module on any of my systems. Something is pinning it
and I have no idea what it is.

drivers/thermal/thermal_sys.c | 116 ++++++++++++++++++++++++++++++++---------
include/linux/thermal.h | 22 -------
2 files changed, 91 insertions(+), 47 deletions(-)

--- linux-2.6.39-rc4.orig/drivers/thermal/thermal_sys.c 2011-04-26 10:30:29.000000000 +0200
+++ linux-2.6.39-rc4/drivers/thermal/thermal_sys.c 2011-04-26 11:05:38.000000000 +0200
@@ -420,6 +420,29 @@ thermal_cooling_device_trip_point_show(s

/* hwmon sys I/F */
#include <linux/hwmon.h>
+
+/* thermal zone devices with the same type share one hwmon device */
+struct thermal_hwmon_device {
+ char type[THERMAL_NAME_LENGTH];
+ struct device *device;
+ int count;
+ struct list_head tz_list;
+ struct list_head node;
+};
+
+struct thermal_hwmon_attr {
+ struct device_attribute attr;
+ char name[16];
+};
+
+/* one temperature input for each thermal zone */
+struct thermal_hwmon_temp {
+ struct list_head hwmon_node;
+ struct thermal_zone_device *tz;
+ struct thermal_hwmon_attr temp_input; /* hwmon sys attr */
+ struct thermal_hwmon_attr temp_crit; /* hwmon sys attr */
+};
+
static LIST_HEAD(thermal_hwmon_list);

static ssize_t
@@ -437,9 +460,10 @@ temp_input_show(struct device *dev, stru
int ret;
struct thermal_hwmon_attr *hwmon_attr
= container_of(attr, struct thermal_hwmon_attr, attr);
- struct thermal_zone_device *tz
- = container_of(hwmon_attr, struct thermal_zone_device,
+ struct thermal_hwmon_temp *temp
+ = container_of(hwmon_attr, struct thermal_hwmon_temp,
temp_input);
+ struct thermal_zone_device *tz = temp->tz;

ret = tz->ops->get_temp(tz, &temperature);

@@ -455,9 +479,10 @@ temp_crit_show(struct device *dev, struc
{
struct thermal_hwmon_attr *hwmon_attr
= container_of(attr, struct thermal_hwmon_attr, attr);
- struct thermal_zone_device *tz
- = container_of(hwmon_attr, struct thermal_zone_device,
+ struct thermal_hwmon_temp *temp
+ = container_of(hwmon_attr, struct thermal_hwmon_temp,
temp_crit);
+ struct thermal_zone_device *tz = temp->tz;
long temperature;
int ret;

@@ -485,10 +510,29 @@ thermal_hwmon_lookup_by_type(const struc
return NULL;
}

+/* Find the temperature input matching a given thermal zone */
+static struct thermal_hwmon_temp *
+thermal_hwmon_lookup_temp(const struct thermal_hwmon_device *hwmon,
+ const struct thermal_zone_device *tz)
+{
+ struct thermal_hwmon_temp *temp;
+
+ mutex_lock(&thermal_list_lock);
+ list_for_each_entry(temp, &hwmon->tz_list, hwmon_node)
+ if (temp->tz == tz) {
+ mutex_unlock(&thermal_list_lock);
+ return temp;
+ }
+ mutex_unlock(&thermal_list_lock);
+
+ return NULL;
+}
+
static int
thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
{
struct thermal_hwmon_device *hwmon;
+ struct thermal_hwmon_temp *temp = NULL;
int new_hwmon_device = 1;
int result;

@@ -515,30 +559,36 @@ thermal_add_hwmon_sysfs(struct thermal_z
goto unregister_hwmon_device;

register_sys_interface:
- tz->hwmon = hwmon;
+ temp = kzalloc(sizeof(struct thermal_hwmon_temp), GFP_KERNEL);
+ if (!temp) {
+ result = -ENOMEM;
+ goto unregister_hwmon_device;
+ }
+
+ temp->tz = tz;
hwmon->count++;

- snprintf(tz->temp_input.name, THERMAL_NAME_LENGTH,
+ snprintf(temp->temp_input.name, THERMAL_NAME_LENGTH,
"temp%d_input", hwmon->count);
- tz->temp_input.attr.attr.name = tz->temp_input.name;
- tz->temp_input.attr.attr.mode = 0444;
- tz->temp_input.attr.show = temp_input_show;
- sysfs_attr_init(&tz->temp_input.attr.attr);
- result = device_create_file(hwmon->device, &tz->temp_input.attr);
+ temp->temp_input.attr.attr.name = temp->temp_input.name;
+ temp->temp_input.attr.attr.mode = 0444;
+ temp->temp_input.attr.show = temp_input_show;
+ sysfs_attr_init(&temp->temp_input.attr.attr);
+ result = device_create_file(hwmon->device, &temp->temp_input.attr);
if (result)
goto unregister_hwmon_device;

if (tz->ops->get_crit_temp) {
unsigned long temperature;
if (!tz->ops->get_crit_temp(tz, &temperature)) {
- snprintf(tz->temp_crit.name, THERMAL_NAME_LENGTH,
+ snprintf(temp->temp_crit.name, THERMAL_NAME_LENGTH,
"temp%d_crit", hwmon->count);
- tz->temp_crit.attr.attr.name = tz->temp_crit.name;
- tz->temp_crit.attr.attr.mode = 0444;
- tz->temp_crit.attr.show = temp_crit_show;
- sysfs_attr_init(&tz->temp_crit.attr.attr);
+ temp->temp_crit.attr.attr.name = temp->temp_crit.name;
+ temp->temp_crit.attr.attr.mode = 0444;
+ temp->temp_crit.attr.show = temp_crit_show;
+ sysfs_attr_init(&temp->temp_crit.attr.attr);
result = device_create_file(hwmon->device,
- &tz->temp_crit.attr);
+ &temp->temp_crit.attr);
if (result)
goto unregister_hwmon_device;
}
@@ -547,14 +597,15 @@ thermal_add_hwmon_sysfs(struct thermal_z
mutex_lock(&thermal_list_lock);
if (new_hwmon_device)
list_add_tail(&hwmon->node, &thermal_hwmon_list);
- list_add_tail(&tz->hwmon_node, &hwmon->tz_list);
+ list_add_tail(&temp->hwmon_node, &hwmon->tz_list);
mutex_unlock(&thermal_list_lock);

return 0;

unregister_hwmon_device:
- device_remove_file(hwmon->device, &tz->temp_crit.attr);
- device_remove_file(hwmon->device, &tz->temp_input.attr);
+ device_remove_file(hwmon->device, &temp->temp_crit.attr);
+ device_remove_file(hwmon->device, &temp->temp_input.attr);
+ kfree(temp);
if (new_hwmon_device) {
device_remove_file(hwmon->device, &dev_attr_name);
hwmon_device_unregister(hwmon->device);
@@ -569,15 +620,30 @@ thermal_add_hwmon_sysfs(struct thermal_z
static void
thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz)
{
- struct thermal_hwmon_device *hwmon = tz->hwmon;
+ struct thermal_hwmon_device *hwmon;
+ struct thermal_hwmon_temp *temp;

- tz->hwmon = NULL;
- device_remove_file(hwmon->device, &tz->temp_input.attr);
+ hwmon = thermal_hwmon_lookup_by_type(tz);
+ if (unlikely(!hwmon)) {
+ /* Should never happen... */
+ dev_dbg(&tz->device, "hwmon device lookup failed!\n");
+ return;
+ }
+
+ temp = thermal_hwmon_lookup_temp(hwmon, tz);
+ if (unlikely(!temp)) {
+ /* Should never happen... */
+ dev_dbg(&tz->device, "temperature input lookup failed!\n");
+ return;
+ }
+
+ device_remove_file(hwmon->device, &temp->temp_input.attr);
if (tz->ops->get_crit_temp)
- device_remove_file(hwmon->device, &tz->temp_crit.attr);
+ device_remove_file(hwmon->device, &temp->temp_crit.attr);

mutex_lock(&thermal_list_lock);
- list_del(&tz->hwmon_node);
+ list_del(&temp->hwmon_node);
+ kfree(temp);
if (!list_empty(&hwmon->tz_list)) {
mutex_unlock(&thermal_list_lock);
return;
--- linux-2.6.39-rc4.orig/include/linux/thermal.h 2011-04-25 16:16:10.000000000 +0200
+++ linux-2.6.39-rc4/include/linux/thermal.h 2011-04-26 10:40:46.000000000 +0200
@@ -85,22 +85,6 @@ struct thermal_cooling_device {
((long)t-2732+5)/10 : ((long)t-2732-5)/10)
#define CELSIUS_TO_KELVIN(t) ((t)*10+2732)

-#if defined(CONFIG_THERMAL_HWMON)
-/* thermal zone devices with the same type share one hwmon device */
-struct thermal_hwmon_device {
- char type[THERMAL_NAME_LENGTH];
- struct device *device;
- int count;
- struct list_head tz_list;
- struct list_head node;
-};
-
-struct thermal_hwmon_attr {
- struct device_attribute attr;
- char name[16];
-};
-#endif
-
struct thermal_zone_device {
int id;
char type[THERMAL_NAME_LENGTH];
@@ -120,12 +104,6 @@ struct thermal_zone_device {
struct mutex lock; /* protect cooling devices list */
struct list_head node;
struct delayed_work poll_queue;
-#if defined(CONFIG_THERMAL_HWMON)
- struct list_head hwmon_node;
- struct thermal_hwmon_device *hwmon;
- struct thermal_hwmon_attr temp_input; /* hwmon sys attr */
- struct thermal_hwmon_attr temp_crit; /* hwmon sys attr */
-#endif
};
/* Adding event notification support elements */
#define THERMAL_GENL_FAMILY_NAME "thermal_event"

--
Jean Delvare
--
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