Btw, while this series relies on the blk_next_bio() patch to work, it
was not the reason that I sent the latter. It was just because the way
it calls bio_chain() doesn't look right to any of the functions that
make use of it (or in other words, the apparent logic of itself).
That's actually why I didn't have it in the same series.
On Sun, 6 Dec 2020 at 22:07, Tom Yan <tom.ty89@xxxxxxxxx> wrote:
>
> Yes it does have "dependency" to the blk_next_bio() patch. I just
> somehow missed that.
>
> The problem is, I don't think I'm trying to change the logic of
> bio_chain(), or even that of blk_next_bio(). It really just looks like
> a careless mistake, that the arguments were typed in the wrong order.
>
> Adding those who signed off the original commit (block: remove struct
> bio_batch / 9082e87b) here too to the CC list.
>
>
> On Sun, 6 Dec 2020 at 21:56, Hannes Reinecke <hare@xxxxxxx> wrote:
> >
> > On 12/6/20 2:25 PM, Tom Yan wrote:
> > > I think you misunderstood it. The goal of this patch is to split the
> > > current situation into two chains (or one unchained bio + a series of
> > > chained bio). The first one is an attempt/trial which makes sure that
> > > the latter large bio chain can actually be handled (as per the
> > > "command capability" of the device).
> > >
> > Oh, I think I do get what you're trying to do. And, in fact, I don't
> > argue with what you're trying to achieve.
> >
> > What I would like to see, though, is keep the current bio_chain logic
> > intact (irrespective of your previous patch, which should actually be
> > part of this series), and just lift the first check out of the loop:
> >
> > @@ -262,9 +262,14 @@ static int __blkdev_issue_write_zeroes(struct
> > block_device *bdev,
> >
> > if (max_write_zeroes_sectors == 0)
> > return -EOPNOTSUPP;
> > -
> > + new = bio_alloc(gfp_mask, 0);
> > + bio_chain(bio, new);
> > + if (submit_bio_wait(bio) == BLK_STS_NOTSUPP) {
> > + bio_put(new);
> > + return -ENOPNOTSUPP;
> > + }
> > + bio = new;
> > while (nr_sects) {
> > - bio = blk_next_bio(bio, 0, gfp_mask);
> > bio->bi_iter.bi_sector = sector;
> > bio_set_dev(bio, bdev);
> > bio->bi_opf = REQ_OP_WRITE_ZEROES;
> > @@ -279,6 +284,7 @@ static int __blkdev_issue_write_zeroes(struct
> > block_device *bdev,
> > bio->bi_iter.bi_size = nr_sects << 9;
> > nr_sects = 0;
> > }
> > + bio = blk_next_bio(bio, 0, gfp_mask);
> > cond_resched();
> > }
> >
> > (The error checking from submit_bio_wait() could be improved :-)
> >
> > Cheers,
> >
> > Hannes
> > --
> > Dr. Hannes Reinecke Kernel Storage Architect
> > hare@xxxxxxx +49 911 74053 688
> > SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
> > HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer
