Re: [PATCH RFC v3 14/15] block: fix disordered IO in the case recursive split

[Yu Kuai <yukuai1@xxxxxxxxxxxxxxx>]

Hi,

在 2025/09/03 1:20, Bart Van Assche 写道:
> On 8/31/25 8:32 PM, Yu Kuai wrote:
> > -void submit_bio_noacct_nocheck(struct bio *bio)
> > +void submit_bio_noacct_nocheck(struct bio *bio, bool split)
> >   {
> >       blk_cgroup_bio_start(bio);
> >       blkcg_bio_issue_init(bio);
> > @@ -745,12 +745,16 @@ void submit_bio_noacct_nocheck(struct bio *bio)
> >        * to collect a list of requests submited by a ->submit_bio 
> > method while
> >        * it is active, and then process them after it returned.
> >        */
> > -    if (current->bio_list)
> > -        bio_list_add(&current->bio_list[0], bio);
> > -    else if (!bdev_test_flag(bio->bi_bdev, BD_HAS_SUBMIT_BIO))
> > +    if (current->bio_list) {
> > +        if (split && !bdev_is_zoned(bio->bi_bdev))
> > +            bio_list_add_head(&current->bio_list[0], bio);
> > +        else
> > +            bio_list_add(&current->bio_list[0], bio);
>
> The above change will cause write errors for zoned block devices. As I
> have shown before, also for zoned block devices, if a bio is split
> insertion must happen at the head of the list. See e.g.
> "Re: [PATCH 1/2] block: Make __submit_bio_noacct() preserve the bio 
> submission order"
> (https://lore.kernel.org/linux-block/a0c89df8-4b33-409c-ba43-f9543fb1b091@xxxxxxx/) 

Do you mean we should remove the bdev_is_zoned() checking? I added this
checking because I'm not quite sure about details in zone device, and
this checking is aimed at prevent functional changes in zone device.

So I don't think this change will cause write errors, the write errors
should already exist before this set, right?

Thanks,
Kuai

> Thanks,
>
> Bart.
> .