FAILED: patch "[PATCH] ACPI: thermal: Do not call acpi_thermal_check() directly" failed to apply to 4.9-stable tree
Subsystems (3)
[email protected]
maintainerThe patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 81b704d3e4674e09781d331df73d76675d5ad8cb Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <[email protected]>
Date: Thu, 14 Jan 2021 19:34:22 +0100
Subject: [PATCH] ACPI: thermal: Do not call acpi_thermal_check() directly
Calling acpi_thermal_check() from acpi_thermal_notify() directly is problematic if _TMP triggers Notify () on the thermal zone for which it has been evaluated (which happens on some systems), because it causes a new acpi_thermal_notify() invocation to be queued up every time and if that takes place too often, an indefinite number of pending work items may accumulate in kacpi_notify_wq over time.
Besides, it is not really useful to queue up a new invocation of acpi_thermal_check() if one of them is pending already.
For these reasons, rework acpi_thermal_notify() to queue up a thermal check instead of calling acpi_thermal_check() directly and only allow one thermal check to be pending at a time. Moreover, only allow one acpi_thermal_check_fn() instance at a time to run thermal_zone_device_update() for one thermal zone and make it return early if it sees other instances running for the same thermal zone.
While at it, fold acpi_thermal_check() into acpi_thermal_check_fn(), as it is only called from there after the other changes made here.
[This issue appears to have been exposed by commit 6d25be5782e4
("sched/core, workqueues: Distangle worker accounting from rq lock"), but it is unclear why it was not visible earlier.]
drivers/acpi/thermal.c +33 -13
@@ -174,6 +174,8 @@ struct acpi_thermal {struct thermal_zone_device *thermal_zone;int kelvin_offset;/* in millidegrees */ struct work_struct thermal_check_work; +struct mutex thermal_check_lock; +refcount_t thermal_check_count; };/* --------------------------------------------------------------------------
@@ -495,14 +497,6 @@ static int acpi_thermal_get_trip_points(struct acpi_thermal *tz)return 0 ; } -static void acpi_thermal_check (void *data) -{ -struct acpi_thermal *tz = data; - -thermal_zone_device_update (tz->thermal_zone, -THERMAL_EVENT_UNSPECIFIED ); -} -/* sys I/F for generic thermal sysfs support */ static int thermal_get_temp (struct thermal_zone_device *thermal,int *temp)
@@ -900,6 +894,12 @@ static void acpi_thermal_unregister_thermal_zone(struct acpi_thermal *tz)Driver Interface -------------------------------------------------------------------------- */ +static void acpi_queue_thermal_check (struct acpi_thermal *tz) +{ +if (!work_pending (&tz->thermal_check_work)) +queue_work (acpi_thermal_pm_queue, &tz->thermal_check_work); +} +static void acpi_thermal_notify (struct acpi_device *device,u32 event) {struct acpi_thermal *tz =acpi_driver_data (device);
@@ -910,17 +910,17 @@ static void acpi_thermal_notify(struct acpi_device *device, u32 event)switch (event) {case ACPI_THERMAL_NOTIFY_TEMPERATURE : -acpi_thermal_check (tz); +acpi_queue_thermal_check (tz);break ;case ACPI_THERMAL_NOTIFY_THRESHOLDS :acpi_thermal_trips_update (tz,ACPI_TRIPS_REFRESH_THRESHOLDS ); -acpi_thermal_check (tz); +acpi_queue_thermal_check (tz);acpi_bus_generate_netlink_event (device->pnp.device_class,dev_name (&device->dev), event,0 );break ;case ACPI_THERMAL_NOTIFY_DEVICES :acpi_thermal_trips_update (tz,ACPI_TRIPS_REFRESH_DEVICES ); -acpi_thermal_check (tz); +acpi_queue_thermal_check (tz);acpi_bus_generate_netlink_event (device->pnp.device_class,dev_name (&device->dev), event,0 );break ;
@@ -1020,7 +1020,25 @@ static void acpi_thermal_check_fn(struct work_struct *work) { struct acpi_thermal *tz = container_of(work, struct acpi_thermal, thermal_check_work); -acpi_thermal_check (tz); + +/* +* In general, it is not sufficient to check the pending bit, because +* subsequent instances of this function may be queued after one of them +* has started running (e.g. if _TMP sleeps). Avoid bailing out if just +* one of them is running, though, because it may have done the actual +* check some time ago, so allow at least one of them to block on the +* mutex while another one is running the update. +*/ +if (!refcount_dec_not_one (&tz->thermal_check_count)) +return ; + +mutex_lock (&tz->thermal_check_lock); + +thermal_zone_device_update (tz->thermal_zone,THERMAL_EVENT_UNSPECIFIED ); + +refcount_inc (&tz->thermal_check_count); + +mutex_unlock (&tz->thermal_check_lock); }static int acpi_thermal_add (struct acpi_device *device)
@@ -1052,6 +1070,8 @@ static int acpi_thermal_add(struct acpi_device *device)if (result) goto free_memory; +refcount_set (&tz->thermal_check_count,3 ); +mutex_init (&tz->thermal_check_lock);INIT_WORK (&tz->thermal_check_work, acpi_thermal_check_fn); pr_info(PREFIX "%s [%s] (%ld C)\n", acpi_device_name(device),
@@ -1117,7 +1137,7 @@ static int acpi_thermal_resume(struct device *dev) tz->state.active |= tz->trips.active[i].flags.enabled; } -queue_work (acpi_thermal_pm_queue, &tz->thermal_check_work); +acpi_queue_thermal_check (tz);return AE_OK ; }