Re: [PATCH] seqlock: avoid -Wshadow warnings

[Rasmus Villemoes]

On 28/10/2020 00.34, Arnd Bergmann wrote:
> On Mon, Oct 26, 2020 at 5:58 PM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>>
>> On Mon, Oct 26, 2020 at 05:50:38PM +0100, Arnd Bergmann wrote:
>>
>>> -     unsigned seq;                                                   \
>>> +     unsigned __seq;                                                 \
>>
>>> -     unsigned seq = __read_seqcount_begin(s);                        \
>>> +     unsigned _seq = __read_seqcount_begin(s);                       \
>>
>>> -     unsigned seq = __seqcount_sequence(s);                          \
>>> +     unsigned __seq = __seqcount_sequence(s);                        \
>>
>> Can we have a consistent number of leading '_' ?
> 
> Not really ;-)
> 
> The warning comes from raw_read_seqcount_begin() calling
> __read_seqcount_begin() and both using the same variable
> name. I could rename one of them  and use double-underscores
> for both, but I haven't come up with a good alternative name
> that wouldn't make it less consistent in the process.

At least x86's put_user and get_user use _pu/_gu suffixes on their local
variables, so perhaps that could be made a weak default convention?

__seq_rsb
__seq_rrsb
__seq_rrs

Hm, or perhaps not. But it's still better than triplicating each macro
to do a UNIQUE_ID dance.

Rasmus