linux-kernel - Re: [PATCH] bus: hisi_lpc: fix missing platform_device_put() in hisi_lpc_acpi

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Date:   Mon, 4 Jul 2022 17:11:49 +0800
From:   Yang Yingliang <yangyingliang@...wei.com>
To:     John Garry <john.garry@...wei.com>, <linux-kernel@...r.kernel.org>
CC:     <andriy.shevchenko@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>
Subject: Re: [PATCH] bus: hisi_lpc: fix missing platform_device_put() in
 hisi_lpc_acpi_probe()


On 2022/7/4 16:01, John Garry wrote:
> On 01/07/2022 10:43, Yang Yingliang wrote:
>
> +
>
> Please send any updated version cc'ing Rafael, who kindly offered to 
> pick up this patch
>
>>
[...]
>> @@ -503,13 +503,13 @@ static int hisi_lpc_acpi_probe(struct device 
>> *hostdev)
>>   {
>>       struct acpi_device *adev = ACPI_COMPANION(hostdev);
>>       struct acpi_device *child;
>> +    struct platform_device *pdev;
>
> nit: please maintain reverse-firtree ordering
OK
>
>>       int ret;
>>         /* Only consider the children of the host */
>>       list_for_each_entry(child, &adev->children, node) {
>>           const char *hid = acpi_device_hid(child);
>>           const struct hisi_lpc_acpi_cell *cell;
>> -        struct platform_device *pdev;
>>           const struct resource *res;
>>           bool found = false;
>>           int num_res;
>> @@ -571,22 +571,24 @@ static int hisi_lpc_acpi_probe(struct device 
>> *hostdev)
>>             ret = platform_device_add_resources(pdev, res, num_res);
>>           if (ret)
>> -            goto fail;
>> +            goto fail_put_device;
>>             ret = platform_device_add_data(pdev, cell->pdata,
>>                              cell->pdata_size);
>>           if (ret)
>> -            goto fail;
>> +            goto fail_put_device;
>>             ret = platform_device_add(pdev);
>>           if (ret)
>> -            goto fail;
>> +            goto fail_put_device;
>>             acpi_device_set_enumerated(child);
>>       }
>>         return 0;
>>   +fail_put_device:
>> +    platform_device_put(pdev);
>
> is this enough? As I see, this invokes platform_device_release(), but 
> we would still need platform_device_del() to drop the pdev resources. 
> hisi_lpc_acpi_remove_subdev() calls platform_device_unregister(), so 
> it seems proper to do that here also. Please check it.
The resource allocated in platform_device_add_resources() is inserted by 
platform_device_add(), if platform_device_add() is not called 
successfully, freeing the resource in platform_device_release() is enough.
>
> Thanks,
> John
>
>>   fail:
>>       hisi_lpc_acpi_remove(hostdev);
>>       return ret;
>
> .