Re: [PATCH v3] net: bluetooth: hci_sock: Use 'const u32 *' instead of 'void *' for 2nd parameter of hci_test_bit()

[Marcel Holtmann]

Hi Chen,

>>>>> So at present, in kernel part, we can only say the original authors
>>>>> intended to do like this. And only within kernel part, it can not cause
>>>>> issue. I guess, original authors originally knew what we talk about.
>>>> 
>>>> I've just searched for hci_u*filter it is all horrid.
>>>> Look at the code for get/set_sockopt of HCI_FILTER.
>>>> Someone seems to have done a complete 'bodge job' of fixing the user interface
>>>> for apps (32bit and 64bit) on 64bit kernels.
>>> 
>>> we are actually fully aware of that. Just keep in mind that this code is from 2.4.6 kernel and with
>>> that most likely 14 years old by now. Unfortunately it ended up as userspace API.
>> 
>> AFAICT the userspace API is always __u32[2] the long[2] is never exposed
>> to userspace (certainly not through the socket option code).
>> 
>> Quite why all the casts were added - instead of changing the type
>> is probably hidden in the annals of the source repo.
>> Some serious archaeology might be in order.
>> 
> 
> For me, I guess what you said above sounds reasonable. But excuse me,
> I am not familiar with the related modules outside Linux kernel (at
> present, it is out of my border).
> 
> I guess, I am not the suitable member to make the related fix patch for
> this issue. Welcome any other members to send the fix patch for it.
> 
> And for me, if "hci_u*filter" is related with the modules outside kernel
> (I guess, it should be), I recommend to put it to the related "uapi"
> header.

since that is such old code, the "uapi" is essentially what we have as libbluetooth from the BlueZ userspace code.

Regards

Marcel

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