LinuxLists.cc - [PATCH v1 10/11] thermal/core: Alloc-copy-free the thermal zone parameters structure

2023-03-07 13:38:30

Subject: [PATCH v1 10/11] thermal/core: Alloc-copy-free the thermal zone parameters structure

The caller of the function thermal_zone_device_register_with_trips()
can pass a thermal_zone_params structure parameter.

This one is used by the thermal core code until the thermal zone is
destroyed. That forces the caller, so the driver, to keep the pointer
valid until it unregisters the thermal zone if we want to make the
thermal zone device structure private the core code.

As the thermal zone device structure would be private, the driver can
not access to thermal zone device structure to retrieve the tzp field
after it passed it to register the thermal zone.

So instead of forcing the users of the function to deal with the tzp
structure life cycle, make the usage easier by allocating our own
thermal zone params, copying the parameter content and by freeing at
unregister time. The user can then create the parameters on the stack,
pass it to the registering function and forget about it.

Signed-off-by: Daniel Lezcano <[email protected]>
---
drivers/thermal/thermal_core.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index ca91189bc441..6cbda8f4522e 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -1263,13 +1263,19 @@ thermal_zone_device_register_with_trips(const char *type, struct thermal_trip *t
if (!tz)
return ERR_PTR(-ENOMEM);

+ if (tzp) {
+ tz->tzp = kmemdup(tzp, sizeof(*tzp), GFP_KERNEL);
+ if (!tz->tzp)
+ goto free_tz;
+ }
+
INIT_LIST_HEAD(&tz->thermal_instances);
ida_init(&tz->ida);
mutex_init(&tz->lock);
id = ida_alloc(&thermal_tz_ida, GFP_KERNEL);
if (id < 0) {
result = id;
- goto free_tz;
+ goto free_tzp;
}

tz->id = id;
@@ -1279,7 +1285,6 @@ thermal_zone_device_register_with_trips(const char *type, struct thermal_trip *t
ops->critical = thermal_zone_device_critical;

tz->ops = ops;
- tz->tzp = tzp;
tz->device.class = thermal_class;
tz->devdata = devdata;
tz->trips = trips;
@@ -1377,6 +1382,8 @@ thermal_zone_device_register_with_trips(const char *type, struct thermal_trip *t
tz = NULL;
remove_id:
ida_free(&thermal_tz_ida, id);
+free_tzp:
+ kfree(tz->tzp);
free_tz:
kfree(tz);
return ERR_PTR(result);
@@ -1472,6 +1479,8 @@ void thermal_zone_device_unregister(struct thermal_zone_device *tz)
device_del(&tz->device);
mutex_unlock(&tz->lock);

+ kfree(tzp);
+
put_device(&tz->device);

thermal_notify_tz_delete(tz_id);
--
2.34.1

2023-03-15 12:54:56

by kernel test robot

[permalink] [raw]

Subject: Re: [PATCH v1 10/11] thermal/core: Alloc-copy-free the thermal zone parameters structure

Hi Daniel,

I love your patch! Perhaps something to improve:

[auto build test WARNING on rafael-pm/linux-next]
[also build test WARNING on linus/master v6.3-rc2 next-20230315]
[cannot apply to rafael-pm/thermal]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url: https://github.com/intel-lab-lkp/linux/commits/Daniel-Lezcano/thermal-drivers-intel_pch_thermal-Use-thermal-driver-device-to-write-a-trace/20230307-223759
base: https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
patch link: https://lore.kernel.org/r/20230307133735.90772-11-daniel.lezcano%40linaro.org
patch subject: [PATCH v1 10/11] thermal/core: Alloc-copy-free the thermal zone parameters structure
config: i386-randconfig-a011-20230313 (https://download.01.org/0day-ci/archive/20230315/[email protected]/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/a9813bacf3531491cb02c13aafe358e6b5423aa0
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Daniel-Lezcano/thermal-drivers-intel_pch_thermal-Use-thermal-driver-device-to-write-a-trace/20230307-223759
git checkout a9813bacf3531491cb02c13aafe358e6b5423aa0
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/thermal/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
| Link: https://lore.kernel.org/oe-kbuild-all/[email protected]/

All warnings (new ones prefixed by >>):

>> drivers/thermal/thermal_core.c:1267:7: warning: variable 'result' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
if (!tz->tzp)
^~~~~~~~
drivers/thermal/thermal_core.c:1388:17: note: uninitialized use occurs here
return ERR_PTR(result);
^~~~~~
drivers/thermal/thermal_core.c:1267:3: note: remove the 'if' if its condition is always false
if (!tz->tzp)
^~~~~~~~~~~~~
drivers/thermal/thermal_core.c:1217:12: note: initialize the variable 'result' to silence this warning
int result;
^
= 0
1 warning generated.

vim +1267 drivers/thermal/thermal_core.c

1183
1184 /**
1185 * thermal_zone_device_register_with_trips() - register a new thermal zone device
1186 * @type: the thermal zone device type
1187 * @trips: a pointer to an array of thermal trips
1188 * @num_trips: the number of trip points the thermal zone support
1189 * @mask: a bit string indicating the writeablility of trip points
1190 * @devdata: private device data
1191 * @ops: standard thermal zone device callbacks
1192 * @tzp: thermal zone platform parameters
1193 * @passive_delay: number of milliseconds to wait between polls when
1194 * performing passive cooling
1195 * @polling_delay: number of milliseconds to wait between polls when checking
1196 * whether trip points have been crossed (0 for interrupt
1197 * driven systems)
1198 *
1199 * This interface function adds a new thermal zone device (sensor) to
1200 * /sys/class/thermal folder as thermal_zone[0-*]. It tries to bind all the
1201 * thermal cooling devices registered at the same time.
1202 * thermal_zone_device_unregister() must be called when the device is no
1203 * longer needed. The passive cooling depends on the .get_trend() return value.
1204 *
1205 * Return: a pointer to the created struct thermal_zone_device or an
1206 * in case of error, an ERR_PTR. Caller must check return value with
1207 * IS_ERR*() helpers.
1208 */
1209 struct thermal_zone_device *
1210 thermal_zone_device_register_with_trips(const char *type, struct thermal_trip *trips, int num_trips, int mask,
1211 void *devdata, struct thermal_zone_device_ops *ops,
1212 struct thermal_zone_params *tzp, int passive_delay,
1213 int polling_delay)
1214 {
1215 struct thermal_zone_device *tz;
1216 int id;
1217 int result;
1218 int count;
1219 struct thermal_governor *governor;
1220
1221 if (!type || strlen(type) == 0) {
1222 pr_err("No thermal zone type defined\n");
1223 return ERR_PTR(-EINVAL);
1224 }
1225
1226 if (strlen(type) >= THERMAL_NAME_LENGTH) {
1227 pr_err("Thermal zone name (%s) too long, should be under %d chars\n",
1228 type, THERMAL_NAME_LENGTH);
1229 return ERR_PTR(-EINVAL);
1230 }
1231
1232 /*
1233 * Max trip count can't exceed 31 as the "mask >> num_trips" condition.
1234 * For example, shifting by 32 will result in compiler warning:
1235 * warning: right shift count >= width of type [-Wshift-count- overflow]
1236 *
1237 * Also "mask >> num_trips" will always be true with 32 bit shift.
1238 * E.g. mask = 0x80000000 for trip id 31 to be RW. Then
1239 * mask >> 32 = 0x80000000
1240 * This will result in failure for the below condition.
1241 *
1242 * Check will be true when the bit 31 of the mask is set.
1243 * 32 bit shift will cause overflow of 4 byte integer.
1244 */
1245 if (num_trips > (BITS_PER_TYPE(int) - 1) || num_trips < 0 || mask >> num_trips) {
1246 pr_err("Incorrect number of thermal trips\n");
1247 return ERR_PTR(-EINVAL);
1248 }
1249
1250 if (!ops) {
1251 pr_err("Thermal zone device ops not defined\n");
1252 return ERR_PTR(-EINVAL);
1253 }
1254
1255 if (num_trips > 0 && (!ops->get_trip_type || !ops->get_trip_temp) && !trips)
1256 return ERR_PTR(-EINVAL);
1257
1258 if (!thermal_class)
1259 return ERR_PTR(-ENODEV);
1260
1261 tz = kzalloc(sizeof(*tz), GFP_KERNEL);
1262 if (!tz)
1263 return ERR_PTR(-ENOMEM);
1264
1265 if (tzp) {
1266 tz->tzp = kmemdup(tzp, sizeof(*tzp), GFP_KERNEL);
> 1267 if (!tz->tzp)
1268 goto free_tz;
1269 }
1270
1271 INIT_LIST_HEAD(&tz->thermal_instances);
1272 ida_init(&tz->ida);
1273 mutex_init(&tz->lock);
1274 id = ida_alloc(&thermal_tz_ida, GFP_KERNEL);
1275 if (id < 0) {
1276 result = id;
1277 goto free_tzp;
1278 }
1279
1280 tz->id = id;
1281 strscpy(tz->type, type, sizeof(tz->type));
1282
1283 if (!ops->critical)
1284 ops->critical = thermal_zone_device_critical;
1285
1286 tz->ops = ops;
1287 tz->device.class = thermal_class;
1288 tz->devdata = devdata;
1289 tz->trips = trips;
1290 tz->num_trips = num_trips;
1291
1292 thermal_set_delay_jiffies(&tz->passive_delay_jiffies, passive_delay);
1293 thermal_set_delay_jiffies(&tz->polling_delay_jiffies, polling_delay);
1294
1295 /* sys I/F */
1296 /* Add nodes that are always present via .groups */
1297 result = thermal_zone_create_device_groups(tz, mask);
1298 if (result)
1299 goto remove_id;
1300
1301 /* A new thermal zone needs to be updated anyway. */
1302 atomic_set(&tz->need_update, 1);
1303
1304 result = dev_set_name(&tz->device, "thermal_zone%d", tz->id);
1305 if (result) {
1306 thermal_zone_destroy_device_groups(tz);
1307 goto remove_id;
1308 }
1309 result = device_register(&tz->device);
1310 if (result)
1311 goto release_device;
1312
1313 for (count = 0; count < num_trips; count++) {
1314 struct thermal_trip trip;
1315
1316 result = thermal_zone_get_trip(tz, count, &trip);
1317 if (result)
1318 set_bit(count, &tz->trips_disabled);
1319 }
1320
1321 /* Update 'this' zone's governor information */
1322 mutex_lock(&thermal_governor_lock);
1323
1324 if (tz->tzp)
1325 governor = __find_governor(tz->tzp->governor_name);
1326 else
1327 governor = def_governor;
1328
1329 result = thermal_set_governor(tz, governor);
1330 if (result) {
1331 mutex_unlock(&thermal_governor_lock);
1332 goto unregister;
1333 }
1334
1335 mutex_unlock(&thermal_governor_lock);
1336
1337 if (!tz->tzp || !tz->tzp->no_hwmon) {
1338 result = thermal_add_hwmon_sysfs(tz);
1339 if (result)
1340 goto unregister;
1341 }
1342
1343 mutex_lock(&thermal_list_lock);
1344 list_add_tail(&tz->node, &thermal_tz_list);
1345 mutex_unlock(&thermal_list_lock);
1346
1347 if (tzp && tzp->linked_dev) {
1348 result = sysfs_create_link(&tzp->linked_dev->kobj,
1349 &tz->device.kobj, "thermal_zone");
1350 if (result)
1351 goto out_list_del;
1352
1353 result = sysfs_create_link(&tz->device.kobj,
1354 &tzp->linked_dev->kobj, "device");
1355 if (result)
1356 goto out_del_link;
1357 }
1358
1359 /* Bind cooling devices for this zone */
1360 bind_tz(tz);
1361
1362 INIT_DELAYED_WORK(&tz->poll_queue, thermal_zone_device_check);
1363
1364 thermal_zone_device_init(tz);
1365 /* Update the new thermal zone and mark it as already updated. */
1366 if (atomic_cmpxchg(&tz->need_update, 1, 0))
1367 thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
1368
1369 thermal_notify_tz_create(tz->id, tz->type);
1370
1371 return tz;
1372
1373 out_del_link:
1374 sysfs_remove_link(&tz->device.kobj, "thermal_zone");
1375 out_list_del:
1376 list_del(&tz->node);
1377 unregister:
1378 device_del(&tz->device);
1379 release_device:
1380 put_device(&tz->device);
1381 tz = NULL;
1382 remove_id:
1383 ida_free(&thermal_tz_ida, id);
1384 free_tzp:
1385 kfree(tz->tzp);
1386 free_tz:
1387 kfree(tz);
1388 return ERR_PTR(result);
1389 }
1390 EXPORT_SYMBOL_GPL(thermal_zone_device_register_with_trips);
1391

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests

2023-03-18 09:07:35

by Dan Carpenter

[permalink] [raw]

Subject: Re: [PATCH v1 10/11] thermal/core: Alloc-copy-free the thermal zone parameters structure