From patchwork Tue Jul 30 18:21:54 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. 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Wysocki" To: Linux PM Cc: LKML , Linux ACPI , Daniel Lezcano , Lukasz Luba , Zhang Rui Subject: [PATCH v1 07/17] thermal: core: Move thermal zone locking out of bind/unbind functions Date: Tue, 30 Jul 2024 20:21:54 +0200 Message-ID: <2681296.7s5MMGUR32@rjwysocki.net> In-Reply-To: <1922131.tdWV9SEqCh@rjwysocki.net> References: <1922131.tdWV9SEqCh@rjwysocki.net> Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CLIENT-IP: 195.136.19.94 X-CLIENT-HOSTNAME: 195.136.19.94 X-VADE-SPAMSTATE: spam:low X-VADE-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgeeftddrjeeggdduvdehucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecujffqoffgrffnpdggtffipffknecuuegrihhlohhuthemucduhedtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenogfuphgrmhfkphculdeftddtmdenucfjughrpefhvfevufffkfgjfhgggfgtsehtufertddttdejnecuhfhrohhmpedftfgrfhgrvghlucflrdcuhgihshhotghkihdfuceorhhjfiesrhhjfiihshhotghkihdrnhgvtheqnecuggftrfgrthhtvghrnhepvdffueeitdfgvddtudegueejtdffteetgeefkeffvdeftddttdeuhfegfedvjefhnecukfhppeduleehrddufeeirdduledrleegnecuufhprghmkfhppeduleehrddufeeirdduledrleegnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepudelhedrudefiedrudelrdelgedphhgvlhhopehkrhgvrggthhgvrhdrlhhotggrlhhnvghtpdhmrghilhhfrhhomhepfdftrghfrggvlhculfdrucghhihsohgtkhhifdcuoehrjhifsehrjhifhihsohgtkhhirdhnvghtqedpnhgspghrtghpthhtohepiedprhgtphhtthhopehlihhnuhigqdhpmhesvhhgvghrrdhkvghrnhgvlhdrohhrghdprhgtphhtthhopehlihhnuhigqdhkvghrnhgvlhesvhhgvghrrdhkvghrnhgvlhdrohhrghdprhgtphhtthhopehlihhnuhigqdgrtghpihesvhhgvghrrdhkvghrnhgvlhdrohhrghdprhgtphhtthhopegurghnihgvlhdrlhgviigtrghnoheslhhinhgrrhhordhorhhgpdhrtghpthhtoheplhhukhgrshiirdhluhgsrgesrghrmhdrtghomhdprhgtphhtthhopehruhhirdiihhgrnhhgsehinhhtvghlrdgtohhm X-DCC--Metrics: v370.home.net.pl 1024; Body=18 Fuz1=18 Fuz2=18 From: Rafael J. Wysocki Since thermal_bind_cdev_to_trip() and thermal_unbind_cdev_from_trip() acquire the thermal zone lock, the locking rules for their callers get complicated. In particular, the thermal zone lock cannot be acquired in any code path leading to one of these functions even though it might be useful to do so. To address this, remove the thermal zone locking from both these functions, add lockdep assertions for the thermal zone lock to both of them and make their callers acquire the thermal zone lock instead. No intentional functional impact. Signed-off-by: Rafael J. Wysocki --- drivers/acpi/thermal.c | 2 +- drivers/thermal/thermal_core.c | 30 ++++++++++++++++++++++-------- 2 files changed, 23 insertions(+), 9 deletions(-) Index: linux-pm/drivers/thermal/thermal_core.c =================================================================== --- linux-pm.orig/drivers/thermal/thermal_core.c +++ linux-pm/drivers/thermal/thermal_core.c @@ -789,6 +789,7 @@ int thermal_bind_cdev_to_trip(struct the int result; lockdep_assert_held(&thermal_list_lock); + lockdep_assert_held(&tz->lock); if (list_empty(&tz->node) || list_empty(&cdev->node)) return -EINVAL; @@ -851,7 +852,6 @@ int thermal_bind_cdev_to_trip(struct the if (result) goto remove_trip_file; - mutex_lock(&tz->lock); mutex_lock(&cdev->lock); list_for_each_entry(instance, &td->thermal_instances, trip_node) { @@ -868,7 +868,6 @@ int thermal_bind_cdev_to_trip(struct the thermal_governor_update_tz(tz, THERMAL_TZ_BIND_CDEV); mutex_unlock(&cdev->lock); - mutex_unlock(&tz->lock); return 0; @@ -892,11 +891,19 @@ int thermal_zone_bind_cooling_device(str unsigned long upper, unsigned long lower, unsigned int weight) { + int ret; + if (trip_index < 0 || trip_index >= tz->num_trips) return -EINVAL; - return thermal_bind_cdev_to_trip(tz, &tz->trips[trip_index].trip, cdev, - upper, lower, weight); + mutex_lock(&tz->lock); + + ret = thermal_bind_cdev_to_trip(tz, &tz->trips[trip_index].trip, cdev, + upper, lower, weight); + + mutex_unlock(&tz->lock); + + return ret; } EXPORT_SYMBOL_GPL(thermal_zone_bind_cooling_device); @@ -919,7 +926,8 @@ int thermal_unbind_cdev_from_trip(struct struct thermal_trip_desc *td = trip_to_trip_desc(trip); struct thermal_instance *pos, *next; - mutex_lock(&tz->lock); + lockdep_assert_held(&tz->lock); + mutex_lock(&cdev->lock); list_for_each_entry_safe(pos, next, &td->thermal_instances, trip_node) { @@ -930,13 +938,11 @@ int thermal_unbind_cdev_from_trip(struct thermal_governor_update_tz(tz, THERMAL_TZ_UNBIND_CDEV); mutex_unlock(&cdev->lock); - mutex_unlock(&tz->lock); goto free; } } mutex_unlock(&cdev->lock); - mutex_unlock(&tz->lock); return -ENODEV; @@ -954,10 +960,18 @@ int thermal_zone_unbind_cooling_device(s int trip_index, struct thermal_cooling_device *cdev) { + int ret; + if (trip_index < 0 || trip_index >= tz->num_trips) return -EINVAL; - return thermal_unbind_cdev_from_trip(tz, &tz->trips[trip_index].trip, cdev); + mutex_lock(&tz->lock); + + ret = thermal_unbind_cdev_from_trip(tz, &tz->trips[trip_index].trip, cdev); + + mutex_unlock(&tz->lock); + + return ret; } EXPORT_SYMBOL_GPL(thermal_zone_unbind_cooling_device); Index: linux-pm/drivers/acpi/thermal.c =================================================================== --- linux-pm.orig/drivers/acpi/thermal.c +++ linux-pm/drivers/acpi/thermal.c @@ -609,7 +609,7 @@ static int acpi_thermal_bind_unbind_cdev .thermal = thermal, .cdev = cdev, .bind = bind }; - return for_each_thermal_trip(thermal, bind_unbind_cdev_cb, &bd); + return thermal_zone_for_each_trip(thermal, bind_unbind_cdev_cb, &bd); } static int