Re: [PATCH v2] md: make md_flush_request() more readable

[Yu Kuai <yukuai1@xxxxxxxxxxxxxxx>]

Hi,

在 2024/05/29 13:44, Christoph Hellwig 写道:
> On Tue, May 28, 2024 at 09:49:44PM +0800, Li Nan wrote:
> > 在 2024/5/28 21:23, Christoph Hellwig 写道:
> > > Looks good:
> > >
> > > Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> > >
> > > .
> > As suggested by Kuai, I will use bio_sectors instead of bi_size in v3.
> >
> > -       if (bio->bi_iter.bi_size == 0) {
> > +       if (!bio_sectors(bio)) {
>
> That looks weird.   bio_sectors literally just shifts
> bio->bi_iter.bi_size to be in units of sectors, which doesn't
> matter for comparing with 0.

The block layer use the same code several times to check if flush bio
contain data, for example:

submit_bio_noacct
 if (op_is_flush(bio->bi_opf))
  if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags))
   if (!bio_sectors(bio))
    bio_endio(bio);

Or will the bi_size to be less than one sector?

Thanks,
Kuai
> .