On 2/5/15 05:09, Marcel Holtmann wrote:
> Hi Sergei,
>
>>>> -static inline int hci_test_bit(int nr, void *addr)
>>>> +static inline int hci_test_bit(int nr, const void *addr)
>>>> {
>>>> return *((__u32 *) addr + (nr >> 5)) & ((__u32) 1 << (nr & 31));
>>>> }
>>
>>> Is there a 'standard' function lurking that will do the above.
>>> On x86 the cpus 'bit test' instruction will handle bit numbers
>>> greater than the word size - so it can be a single instruction.
>>
>> Of course, there's test_bit().
>
> we did leave hci_test_bit in the code since there are some userspace facing
> API that we can not change. Remember that the origin of this code is from
> 2.4.6 kernel.
>
> So we can only change this if you can ensure not to break the userspace API.
> So might want to write unit tests to ensure working HCI filter before even
> considering touching this.
>
For me, we have to remain hci_test_bit(), it is for "__u32 *" (which we
can not change). The common test_bit() is for "unsigned long *", in this
case, I guess it may cause issue under 64-bit environments.
Thanks.
--
Chen Gang
Open, share, and attitude like air, water, and life which God blessed
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