linux-kernel - Re: [PATCH -next 2/5] drm/mediatek: Fix missing of_node_put() for mtk_drm_get_all_drm

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Message-ID: <9f93fe1f-c7d7-7d96-44ab-2bca0aae407e@huawei.com>
Date: Tue, 27 Aug 2024 09:42:30 +0800
From: Jinjie Ruan <ruanjinjie@...wei.com>
To: Marion & Christophe JAILLET <christophe.jaillet@...adoo.fr>,
	<hjc@...k-chips.com>, <heiko@...ech.de>, <andy.yan@...k-chips.com>,
	<maarten.lankhorst@...ux.intel.com>, <mripard@...nel.org>,
	<tzimmermann@...e.de>, <airlied@...il.com>, <daniel@...ll.ch>,
	<dri-devel@...ts.freedesktop.org>, <linux-arm-kernel@...ts.infradead.org>,
	<linux-rockchip@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
	<krzk@...nel.org>, <jic23@...nel.org>
Subject: Re: [PATCH -next 2/5] drm/mediatek: Fix missing of_node_put() for
 mtk_drm_get_all_drm_priv()



On 2024/8/25 13:16, Marion & Christophe JAILLET wrote:
> 
> 
> Le 23/08/2024 à 12:46, Christophe JAILLET a écrit :
>>> @@ -933,10 +931,8 @@ static int mtk_drm_probe(struct platform_device
>>> *pdev)
>>>           }
>>>           ret = mtk_ddp_comp_init(node, &private->ddp_comp[comp_id],
>>> comp_id);
>>> -        if (ret) {
>>> -            of_node_put(node);
>>> +        if (ret)
>>>               goto err_node;
>>
>> Hi,
>>
>> I've seen on another thread that is was not sure that scoped versions
>> and gotos played well together.
>>
>> It was asked to check more in details and confirm that it was safe
>> before applying the patch.
>>
>> I've not followed the discussion, so I just point it out, in case it
>> helps.
>>
>> I'll try to give it a look in the coming days.
>>
>>
>> CJ
>>
> 
> Hi,
> looking at the generated asm file (gcc 14.2.1), everything looks fine.

Yes, as I pointed out in another thread, the test show that goto with
this scoped function is good.

> 
> # drivers/gpu/drm/mediatek/mtk_drm_drv.c:933:         ret =
> mtk_ddp_comp_init(node, &private->ddp_comp[comp_id], comp_id);
>     salq    $5, %rax    #, _36
>     movl    %r14d, %edx    # comp_id,
>     movq    %rbx, %rdi    # node,
>     leaq    552(%rbp,%rax), %rsi    #, _28
>     call    mtk_ddp_comp_init    #
>     movl    %eax, %r12d    # tmp205, <retval>
> # drivers/gpu/drm/mediatek/mtk_drm_drv.c:934:         if (ret)
>     testl    %eax, %eax    # <retval>
>     jne    .L212    #,
> 
> ...
> 
> .L212:
> # ./include/linux/of.h:138: DEFINE_FREE(device_node, struct device_node
> *, if (_T) of_node_put(_T))
>     movq    %rbx, %rdi    # node,
>     call    of_node_put    #
>     jmp    .L171    #
> 
> CJ
>