Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Content-Type: text/plain;
        charset=utf-8
Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3731.200.110.1.12\))
Subject: Re: [PATCH 02/13] leds: el15203000: Fix devm vs. non-devm ordering
From:   Oleh Kravchenko <oleg@kaa.org.ua>
In-Reply-To: <c53e4614-eb06-cda8-f9da-2ca58396df54@huawei.com>
Date:   Fri, 11 Nov 2022 12:39:22 +0200
Cc:     linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org,
        Pavel Machek <pavel@ucw.cz>,
        "weiyongjun (A)" <weiyongjun1@huawei.com>
Content-Transfer-Encoding: 8BIT
Message-Id: <AA4E5187-59BC-4E04-B392-7BD48F0443A1@kaa.org.ua>
References: <1667983694-15040-1-git-send-email-wangyufen@huawei.com>
 <1667983694-15040-3-git-send-email-wangyufen@huawei.com>
 <5D15416B-1866-4031-9958-7CD763C0BD6E@kaa.org.ua>
 <bbd67e6a-8ce0-dbe8-6ab1-9d4a015f4ee9@huawei.com>
 <6D18A607-EC63-495F-BA2D-78E0DB056D3C@kaa.org.ua>
 <c53e4614-eb06-cda8-f9da-2ca58396df54@huawei.com>
To:     wangyufen <wangyufen@huawei.com>
Precedence: bulk

Hello Wang,

> 11 лист. 2022 р. о 11:21 wangyufen <wangyufen@huawei.com> написав(ла):
> 
> 
> 在 2022/11/9 18:43, Oleh Kravchenko 写道:
>> 
>> 
>>> 9 лист. 2022 р. о 12:25 wangyufen <wangyufen@huawei.com> написав(ла):
>>> 
>>> 
>>> 在 2022/11/9 17:39, Oleh Kravchenko 写道:
>>> 
>>>>> -static void el15203000_remove(struct spi_device *spi)
>>>>> 
>>>> Is remove() callback from struct spi_driver deprecated?
>>>> 
>>> It is not that remove() callback is deprecated,
>>> it's that after wrapping mutex_destroy() call with devm_add_action_or_reset(),
>>> remove() callback is unnecessary here.
>>> 
>> When remove() is called, the memory allocated by devm_*() is valid.
>> So what you try to fix here?
> 
> Fix the &priv->lock used after destroy, for details, please see patch #0
> LKML: Wang Yufen: [PATCH 00/13] leds: Fix devm vs. non-devm ordering

It doesn’t make any sense for me.
You saying that remove() called before devm_* allocation
if it true then set_brightness_delayed() will crash the system in anyway.

LED device has a parent SPI device; LED device can’t exist without SPI device.

So deallocation order should be next:
1. LED device devm_*()
2. SPI device remove()