Re: [PATCH v2 11/51] md: raid1: initialize bvec table via bio_add_page()

Guoqing Jiang
2017-06-29T01:36:55Z

On 06/28/2017 12:22 AM, Ming Lei wrote:
>
>> Seems above section is similar as reset_bvec_table introduced in next patch,
>> why there is difference between raid1 and raid10? Maybe add reset_bvec_table
>> into md.c, then call it in raid1 or raid10 is better, just my 2 cents.
> Hi Guoqing,
>
> I think it is a good idea, and even the two patches can be put into
> one, so how about the following patch?

Looks good.

Acked-by: Guoqing Jiang <gqjiang@suse.com>

Thanks,
Guoqing

>
> Shaohua, what do you think of this one?
>
> ---
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 3d957ac1e109..7ffc622dd7fa 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -9126,6 +9126,24 @@ void md_reload_sb(struct mddev *mddev, int nr)
> }
> EXPORT_SYMBOL(md_reload_sb);
>
> +/* generally called after bio_reset() for reseting bvec */
> +void reset_bvec_table(struct bio *bio, struct resync_pages *rp, int size)
> +{
> + /* initialize bvec table again */
> + rp->idx = 0;
> + do {
> + struct page *page = resync_fetch_page(rp, rp->idx++);
> + int len = min_t(int, size, PAGE_SIZE);
> +
> + /*
> + * won't fail because the vec table is big
> + * enough to hold all these pages
> + */
> + bio_add_page(bio, page, len, 0);
> + size -= len;
> + } while (rp->idx < RESYNC_PAGES && size > 0);
> +}
> +
> #ifndef MODULE
>
> /*
> diff --git a/drivers/md/md.h b/drivers/md/md.h
> index 991f0fe2dcc6..f569831b1de9 100644
> --- a/drivers/md/md.h
> +++ b/drivers/md/md.h
> @@ -783,4 +783,6 @@ static inline struct page *resync_fetch_page(struct resync_pages *rp,
> return NULL;
> return rp->pages[idx];
> }
> +
> +void reset_bvec_table(struct bio *bio, struct resync_pages *rp, int size);
> #endif /* _MD_MD_H */
> diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
> index 3febfc8391fb..6ae2665ecd58 100644
> --- a/drivers/md/raid1.c
> +++ b/drivers/md/raid1.c
> @@ -2086,10 +2086,7 @@ static void process_checks(struct r1bio *r1_bio)
> /* Fix variable parts of all bios */
> vcnt = (r1_bio->sectors + PAGE_SIZE / 512 - 1) >> (PAGE_SHIFT - 9);
> for (i = 0; i < conf->raid_disks * 2; i++) {
> - int j;
> - int size;
> blk_status_t status;
> - struct bio_vec *bi;
> struct bio *b = r1_bio->bios[i];
> struct resync_pages *rp = get_resync_pages(b);
> if (b->bi_end_io != end_sync_read)
> @@ -2098,8 +2095,6 @@ static void process_checks(struct r1bio *r1_bio)
> status = b->bi_status;
> bio_reset(b);
> b->bi_status = status;
> - b->bi_vcnt = vcnt;
> - b->bi_iter.bi_size = r1_bio->sectors << 9;
> b->bi_iter.bi_sector = r1_bio->sector +
> conf->mirrors[i].rdev->data_offset;
> b->bi_bdev = conf->mirrors[i].rdev->bdev;
> @@ -2107,15 +2102,8 @@ static void process_checks(struct r1bio *r1_bio)
> rp->raid_bio = r1_bio;
> b->bi_private = rp;
>
> - size = b->bi_iter.bi_size;
> - bio_for_each_segment_all(bi, b, j) {
> - bi->bv_offset = 0;
> - if (size > PAGE_SIZE)
> - bi->bv_len = PAGE_SIZE;
> - else
> - bi->bv_len = size;
> - size -= PAGE_SIZE;
> - }
> + /* initialize bvec table again */
> + reset_bvec_table(b, rp, r1_bio->sectors << 9);
> }
> for (primary = 0; primary < conf->raid_disks * 2; primary++)
> if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index 5026e7ad51d3..72f4fa07449b 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -2087,8 +2087,8 @@ static void sync_request_write(struct mddev *mddev, struct r10bio *r10_bio)
> rp = get_resync_pages(tbio);
> bio_reset(tbio);
>
> - tbio->bi_vcnt = vcnt;
> - tbio->bi_iter.bi_size = fbio->bi_iter.bi_size;
> + reset_bvec_table(tbio, rp, fbio->bi_iter.bi_size);
> +
> rp->raid_bio = r10_bio;
> tbio->bi_private = rp;
> tbio->bi_iter.bi_sector = r10_bio->devs[i].addr;
>
> Thanks,
> Ming
>