Re: [PATCH v3 4/4] rtw88: Fix Sparse warning for rtw8821c_hw_spec

[Kalle Valo <kvalo@kernel.org>]

Ping-Ke Shih <pkshih@realtek.com> writes:

>> -----Original Message-----
>> From: Kalle Valo <kvalo@kernel.org>
>> Sent: Wednesday, June 8, 2022 3:45 PM
>> To: Ping-Ke Shih <pkshih@realtek.com>
>> Cc: Larry Finger <Larry.Finger@lwfinger.net>; Nathan Chancellor
>> <nathan@kernel.org>; Johannes Berg
>> <johannes@sipsolutions.net>; linux-wireless@vger.kernel.org
>> Subject: Re: [PATCH v3 4/4] rtw88: Fix Sparse warning for rtw8821c_hw_spec
>> 
>> Ping-Ke Shih <pkshih@realtek.com> writes:
>> 
>> >
>> > The ch_param[3] is only used by 8821c, so it doesn't affect other devices.
>> > I will prepare a patch to fix it.
>> 
>> But why didn't the compiler catch this? Is there some evil cast
>> somewhere which removes the const? We should fix that as well (in a
>> separate patch).
>> 
>
> This is because we assign a const to .driver_data that is non-const kernel_ulong_t:
>
> static const struct pci_device_id rtw_8821ce_id_table[] = {
> 	{
> 		.driver_data = (kernel_ulong_t)&rtw8821c_hw_spec
> 	},
>
> When casting it back in pci_probe(), we need to add 'const' after Larry's patches:
>
> rtwdev->chip = (struct rtw_chip_info *)id->driver_data;

Yeah, that definitely needs to be const.

> I will prepare another patch to fix that.

Great, thanks!

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