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SubjectRe: [PATCH v4 1/2] clk: hisilicon: Use correct return value about hisi_reset_init()
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On 05/29/2020 11:58 AM, Stephen Boyd wrote:
> Quoting Tiezhu Yang (2020-05-28 19:03:54)
>> On 05/29/2020 07:15 AM, Stephen Boyd wrote:
>>> Quoting Tiezhu Yang (2020-05-27 19:27:42)
>>>> On 05/28/2020 03:06 AM, Stephen Boyd wrote:
>>>>> Quoting Tiezhu Yang (2020-05-27 07:39:21)
>>>>>> The return value about hisi_reset_init() is not correct, fix it.
>>>>>>
>>>>>> Fixes: e9a2310fb689 ("reset: hisilicon: fix potential NULL pointer dereference")
>>>>> hisi_reset_init() returns NULL on error in that commit. This patch
>>>>> doesn't make sense.
>>>> Hi Stephen,
>>>>
>>>> The initial aim of this patch is to use correct return value about
>>>> hisi_reset_init(), maybe NULL is OK, but the return value in this
>>>> patch is more accurate.
>>> The implementation of hisi_reset_init() that I see is this:
>>>
>>>
>>> struct hisi_reset_controller *rstc;
>>>
>>> rstc = devm_kmalloc(&pdev->dev, sizeof(*rstc), GFP_KERNEL);
>>> if (!rstc)
>>> return NULL;
>>>
>>> rstc->membase = devm_platform_ioremap_resource(pdev, 0);
>>> if (IS_ERR(rstc->membase))
>>> return NULL;
>>>
>>> spin_lock_init(&rstc->lock);
>>> rstc->rcdev.owner = THIS_MODULE;
>>> rstc->rcdev.ops = &hisi_reset_ops;
>>> rstc->rcdev.of_node = pdev->dev.of_node;
>>> rstc->rcdev.of_reset_n_cells = 2;
>>> rstc->rcdev.of_xlate = hisi_reset_of_xlate;
>>> reset_controller_register(&rstc->rcdev);
>>>
>>> return rstc;
>>>
>>> And that returns NULL on an error and a valid pointer on success.
>>> Changing the code to check the return value of hisi_reset_init() for an
>>> error pointer is simply wrong without updating hisi_reset_init() to
>>> return an error pointer on error. Where is the patch that changes
>>> hisi_reset_init() to return an error pointer?
>> Hi Stephen,
>>
>> Do you mean the following changes?
> Yes where is this change?

ERR_PTR(-ENOMEM) and ERR_CAST(rstc->membase)


rstc = devm_kmalloc(&pdev->dev, sizeof(*rstc), GFP_KERNEL);
if (!rstc)
- return NULL;
+ return ERR_PTR(-ENOMEM);

rstc->membase = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(rstc->membase))
- return NULL;
+ return ERR_CAST(rstc->membase);



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