Re: [PATCH RFC 3/4] gpio: loongson-64bit: Add shared interrupt support

[Miao Wang <shankerwangmiao@gmail.com>]

Hi,

> 2026年10月2日 03:43，Linus Walleij <linusw@kernel.org> 写道：
> 
> On Thu, Oct 1, 2026 at 7:47 PM Miao Wang <shankerwangmiao@gmail.com> wrote:
> 
>>>>> +       unsigned int usedby : 31;
>>>> 
>>>> Is this a bitmap? Then use a bitmap abstraction.
>>> 
>>> When exclusive is 1, it is a pure number while when exclusive is 0,
>>> it is a bitmap.
>> 
>> To correct my self, usedby is not a bitmap. When exclusive is 1, it stores the using pin
>> id, while when exclusive is zero, it is a counter which stores the number of using pins.
> 
> But what is this mess with using 31 bits for the pin ID?
> 
> How many bits does it *actually* need, using 31 bits looks
> like some way to try to help the compiler to optimize the struct
> which is pointless because the struct isn't even suffixed with
> __packed...

Ah, you are right about it. I intended to reduce the memory that
is needed to hold the struct. However I realized that by using
bit fields, the memory cannot be saved due to the alignment. Will
change in next version.

Cheers,

Miao Wang