linux-kernel - Re: [PATCH v3 05/14] thermal: core: Move thermal zone locking out of bind/unbind functions

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Message-ID: <93639d68-e396-a782-410c-f7827dbd54f5@huawei.com>
Date: Wed, 21 Aug 2024 17:02:31 +0800
From: "lihuisong (C)" <lihuisong@...wei.com>
To: "Rafael J. Wysocki" <rafael@...nel.org>
CC: "Rafael J. Wysocki" <rjw@...ysocki.net>, Linux PM
	<linux-pm@...r.kernel.org>, LKML <linux-kernel@...r.kernel.org>, Daniel
 Lezcano <daniel.lezcano@...aro.org>, Lukasz Luba <lukasz.luba@....com>, Zhang
 Rui <rui.zhang@...el.com>
Subject: Re: [PATCH v3 05/14] thermal: core: Move thermal zone locking out of
 bind/unbind functions


在 2024/8/20 18:27, Rafael J. Wysocki 写道:
> On Tue, Aug 20, 2024 at 10:27 AM lihuisong (C) <lihuisong@...wei.com> wrote:
>>
>> 在 2024/8/19 23:58, Rafael J. Wysocki 写道:
>>> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>>>
>>> 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 <rafael.j.wysocki@...el.com>
>>> ---
>>>
>>> v2 -> v3: Rebase after dropping patches [04-05/17] from the series
>>>
>>> v1 -> v2: No changes
>>>
>>> ---
>>>    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
>>> @@ -785,6 +785,7 @@ int thermal_bind_cdev_to_trip(struct the
>>>        int result;
>>>
>> <snip>
>>> 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);
>> If so, it seems that the for_each_thermal_trip() can be removed or no
>> need to export.
> I beg to differ:
>
> $ git grep for_each_thermal_trip | head -1
> drivers/net/wireless/intel/iwlwifi/mvm/tt.c:
> for_each_thermal_trip(mvm->tz_device.tzone, iwl_trip_temp_cb, &twd);
Can we modify it for tt.c?
It doesn't seem to keep two interfaces. I'm a little confused for that.
> .