[PATCH V2 05/13] block: only account passthrough IO from userspace

[Ming Lei]

On Wed, Jan 26, 2022 at 06:50:03AM +0100, Christoph Hellwig wrote:
> On Tue, Jan 25, 2022 at 05:09:42PM +0800, Ming Lei wrote:
> > Follows another simple way by accounting all request with bio attached,
> > except for requests with kernel buffer.
> 
> > -	else if (rq->q->disk)
> > +	else if (rq->q->disk && rq->bio)
> >  		rq->part = rq->q->disk->part0;
> 
> Most passthrough requests will have a bio, so you'll still use e.g.
> the sd gendisk for sg request here.
> 
> I think the right way would be to just remove this branch entirely.
> This means we only account bios with a block_device, which implies
> they have a gendisk.

That will not account userspace IO, and people may complain.

We can just account passthrough request from userspace by the patch
in my last email.


Thanks, 
Ming