On Sun, 6 Dec 2020 at 19:29, Hannes Reinecke <hare@xxxxxxx> wrote:
>
> On 12/6/20 6:53 AM, Tom Yan wrote:
> > Instead of using the same check for the two layers of loops, count
> > bio pages in the inner loop instead.
> >
> > Signed-off-by: Tom Yan <tom.ty89@xxxxxxxxx>
> > ---
> > block/blk-lib.c | 11 +++++------
> > 1 file changed, 5 insertions(+), 6 deletions(-)
> >
> > diff --git a/block/blk-lib.c b/block/blk-lib.c
> > index c1e9388a8fb8..354dcab760c7 100644
> > --- a/block/blk-lib.c
> > +++ b/block/blk-lib.c
> > @@ -318,7 +318,7 @@ static int __blkdev_issue_zero_pages(struct block_device *bdev,
> > struct request_queue *q = bdev_get_queue(bdev);
> > struct bio *bio = *biop;
> > int bi_size = 0;
> > - unsigned int sz;
> > + unsigned int sz, bio_nr_pages;
> >
> > if (!q)
> > return -ENXIO;
> > @@ -327,19 +327,18 @@ static int __blkdev_issue_zero_pages(struct block_device *bdev,
> > return -EPERM;
> >
> > while (nr_sects != 0) {
> > - bio = blk_next_bio(bio, __blkdev_sectors_to_bio_pages(nr_sects),
> > - gfp_mask);
> > + bio_nr_pages = __blkdev_sectors_to_bio_pages(nr_sects);
> > + bio = blk_next_bio(bio, bio_nr_pages, gfp_mask);
> > bio->bi_iter.bi_sector = sector;
> > bio_set_dev(bio, bdev);
> > bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
> >
> > - while (nr_sects != 0) {
> > + while (bio_nr_pages != 0) {
> > sz = min((sector_t) PAGE_SIZE, nr_sects << 9);
>
> nr_sects will need to be modified, too, if we iterate over bio_nr_pages
> instead of nr_sects.
>
> > bi_size = bio_add_page(bio, ZERO_PAGE(0), sz, 0);
> > nr_sects -= bi_size >> 9;
Not sure what modification you are suggesting. We are still deducting
from it the "added" sectors.
> > sector += bi_size >> 9;
> > - if (bi_size < sz)
> > - break;
> > + bio_nr_pages--;
> > }
> > cond_resched();
> > }
> >
>
> 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
