From 36af2d5c4433fb40ee2af912c4ac0a30991aecfc Mon Sep 17 00:00:00 2001 From: Kai-Heng Feng Date: Fri, 22 Jan 2021 20:53:02 +0800 Subject: ACPI: sysfs: Prefer "compatible" modalias Commit 8765c5ba1949 ("ACPI / scan: Rework modalias creation when "compatible" is present") may create two "MODALIAS=" in one uevent file if specific conditions are met. This breaks systemd-udevd, which assumes each "key" in one uevent file to be unique. The internal implementation of systemd-udevd overwrites the first MODALIAS with the second one, so its kmod rule doesn't load the driver for the first MODALIAS. So if both the ACPI modalias and the OF modalias are present, use the latter to ensure that there will be only one MODALIAS. Link: https://github.com/systemd/systemd/pull/18163 Suggested-by: Mika Westerberg Fixes: 8765c5ba1949 ("ACPI / scan: Rework modalias creation when "compatible" is present") Signed-off-by: Kai-Heng Feng Reviewed-by: Mika Westerberg Reviewed-by: Greg Kroah-Hartman Cc: 4.1+ # 4.1+ [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki --- drivers/acpi/device_sysfs.c | 20 ++++++-------------- 1 file changed, 6 insertions(+), 14 deletions(-) diff --git a/drivers/acpi/device_sysfs.c b/drivers/acpi/device_sysfs.c index 96869f1538b9..bfca116482b8 100644 --- a/drivers/acpi/device_sysfs.c +++ b/drivers/acpi/device_sysfs.c @@ -251,20 +251,12 @@ int __acpi_device_uevent_modalias(struct acpi_device *adev, if (add_uevent_var(env, "MODALIAS=")) return -ENOMEM; - len = create_pnp_modalias(adev, &env->buf[env->buflen - 1], - sizeof(env->buf) - env->buflen); - if (len < 0) - return len; - - env->buflen += len; - if (!adev->data.of_compatible) - return 0; - - if (len > 0 && add_uevent_var(env, "MODALIAS=")) - return -ENOMEM; - - len = create_of_modalias(adev, &env->buf[env->buflen - 1], - sizeof(env->buf) - env->buflen); + if (adev->data.of_compatible) + len = create_of_modalias(adev, &env->buf[env->buflen - 1], + sizeof(env->buf) - env->buflen); + else + len = create_pnp_modalias(adev, &env->buf[env->buflen - 1], + sizeof(env->buf) - env->buflen); if (len < 0) return len; -- cgit v1.2.3 From 81b704d3e4674e09781d331df73d76675d5ad8cb Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 14 Jan 2021 19:34:22 +0100 Subject: 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.] BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=208877 Reported-by: Stephen Berman Diagnosed-by: Sebastian Andrzej Siewior Signed-off-by: Rafael J. Wysocki Reviewed-by: Sebastian Andrzej Siewior Tested-by: Stephen Berman Cc: All applicable --- drivers/acpi/thermal.c | 46 +++++++++++++++++++++++++++++++++------------- 1 file changed, 33 insertions(+), 13 deletions(-) diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c index 12c0ece746f0..859b1de31ddc 100644 --- a/drivers/acpi/thermal.c +++ b/drivers/acpi/thermal.c @@ -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; } -- cgit v1.2.3