Re: [PATCH 1/3] block: don't show disk stats if io accounting is disabled

[yukuai (C)]

在 2022/03/17 22:06, Bart Van Assche 写道:
> On 3/17/22 04:26, Yu Kuai wrote:
> > If io accounting is disabled, there is no point to handle such device
> > in diskstats_show(), and it can be confused for users because all fields
> > in iostat are zero while the disk is handling io.
> >
> > Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
> > ---
> >   block/genhd.c | 5 +++++
> >   1 file changed, 5 insertions(+)
> >
> > diff --git a/block/genhd.c b/block/genhd.c
> > index c3b32c665aec..e5307f512185 100644
> > --- a/block/genhd.c
> > +++ b/block/genhd.c
> > @@ -937,6 +937,9 @@ ssize_t part_stat_show(struct device *dev,
> >       struct disk_stats stat;
> >       unsigned int inflight;
> > +    if (!blk_queue_io_stat(q))
> > +        return sprintf(buf, "io accounting is disabled\n");
> > +
>
> Hmm ... the above looks sub-optimal to me. Has it been considered to 
> return an error code instead or even better to hide the stat attribute 
> if I/O accounting is disabled? The latter can be achieved by modifying 
> disk_visible().

Hi,

It's right this way is much better, i'll hide the 'stat' in next
iteration.

BTW, do you have any suggestion about patch 3?

Thanks,
Kuai