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
