Re: [PATCH v10 06/10] io_uring: introduce attributes for read/write and PI support

[Anuj Gupta <anuj20.g@xxxxxxxxxxx>]

On Tue, Nov 26, 2024 at 01:01:03PM +0000, Pavel Begunkov wrote:
> On 11/25/24 07:06, Anuj Gupta wrote:
> ...
> > +	/* type specific struct here */
> > +	struct io_uring_attr_pi	pi;
> > +};
> 
> This also looks PI specific but with a generic name. Or are
> attribute structures are supposed to be unionised?

Yes, attribute structures would be unionised here. This is done so that
"attr_type" always remains at the top. When there are multiple attributes
this structure would look something like this:

/* attribute information along with type */
struct io_uring_attr {
	enum io_uring_attr_type attr_type;
	/* type specific struct here */
	union {
		struct io_uring_attr_pi	pi;
		struct io_uring_attr_x	x;
		struct io_uring_attr_y	y;
	};
};

And then on the application side for sending attribute x, one would do:

io_uring_attr attr;
attr.type = TYPE_X;
prepare_attr(&attr.x);