linux-kernel - Re: [PATCH v3 02/14] thermal: core: Rearrange checks in thermal_bind_cdev_to

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Message-ID: <66bb19a0-00ba-40a5-91ef-73368659b30a@linaro.org>
Date: Wed, 21 Aug 2024 11:28:27 +0200
From: Daniel Lezcano <daniel.lezcano@...aro.org>
To: "lihuisong (C)" <lihuisong@...wei.com>,
 "Rafael J. Wysocki" <rjw@...ysocki.net>, Linux PM <linux-pm@...r.kernel.org>
Cc: LKML <linux-kernel@...r.kernel.org>, Lukasz Luba <lukasz.luba@....com>,
 Zhang Rui <rui.zhang@...el.com>
Subject: Re: [PATCH v3 02/14] thermal: core: Rearrange checks in
 thermal_bind_cdev_to_trip()

On 21/08/2024 10:49, lihuisong (C) wrote:

[ ... ]

>> -    list_for_each_entry(pos2, &thermal_cdev_list, node) {
>> -        if (pos2 == cdev)
>> -            break;
>> -    }
>> +    lockdep_assert_held(&thermal_list_lock);
>> -    if (tz != pos1 || cdev != pos2)
>> +    if (list_empty(&tz->node) || list_empty(&cdev->node))
> The old verification is ensure that tz and cdev already add to 
> thermal_tz_list and thermal_cdev_list，respectively.
> Namely, tz and cdev are definitely registered and intialized.
> The check is ok for all untizalized thermal_zone_device and cooling device.
> But the new verification doesn't seem to do that.

If the tz or the cdev are registered then their "->node" is not empty 
because they are linked with the thermal_list and cdev_list

So either way is browsing the lists to find the tz/cdev or just check 
"->node" is not empty. The latter the faster.

Did I misunderstood your comment ?

[ ... ]

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