On Wed, Jul 12 2017, Ming Lei wrote:
> bio_add_page() won't fail for resync bio, and the page index for each
> bio is same, so remove it.
>
> More importantly the 'idx' of 'struct resync_pages' is initialized in
> mempool allocator function, this way is wrong since mempool is only
> responsible for allocation, we can't use that for initialization.
>
> Suggested-by: NeilBrown <neilb@xxxxxxxx>
> Reported-by: NeilBrown <neilb@xxxxxxxx>
> Fixes: f0250618361d(md: raid10: don't use bio's vec table to manage resync pages)
> Fixes: 98d30c5812c3(md: raid1: don't use bio's vec table to manage resync pages)
> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
> ---
> drivers/md/md.h | 1 -
> drivers/md/raid1.c | 6 +++---
> drivers/md/raid10.c | 6 +++---
> 3 files changed, 6 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/md/md.h b/drivers/md/md.h
> index 991f0fe2dcc6..2c780aa8d07f 100644
> --- a/drivers/md/md.h
> +++ b/drivers/md/md.h
> @@ -736,7 +736,6 @@ static inline void mddev_check_write_zeroes(struct mddev *mddev, struct bio *bio
>
> /* for managing resync I/O pages */
> struct resync_pages {
> - unsigned idx; /* for get/put page from the pool */
> void *raid_bio;
> struct page *pages[RESYNC_PAGES];
> };
> diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
> index 3febfc8391fb..7901ddc3362f 100644
> --- a/drivers/md/raid1.c
> +++ b/drivers/md/raid1.c
> @@ -170,7 +170,6 @@ static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
> resync_get_all_pages(rp);
> }
>
> - rp->idx = 0;
> rp->raid_bio = r1_bio;
> bio->bi_private = rp;
> }
> @@ -2619,6 +2618,7 @@ static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr,
> int good_sectors = RESYNC_SECTORS;
> int min_bad = 0; /* number of sectors that are bad in all devices */
> int idx = sector_to_idx(sector_nr);
> + int page_idx = 0;
>
> if (!conf->r1buf_pool)
> if (init_resync(conf))
> @@ -2846,7 +2846,7 @@ static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr,
> bio = r1_bio->bios[i];
> rp = get_resync_pages(bio);
> if (bio->bi_end_io) {
> - page = resync_fetch_page(rp, rp->idx++);
> + page = resync_fetch_page(rp, page_idx);
>
> /*
> * won't fail because the vec table is big
> @@ -2858,7 +2858,7 @@ static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr,
> nr_sectors += len>>9;
> sector_nr += len>>9;
> sync_blocks -= (len>>9);
> - } while (get_resync_pages(r1_bio->bios[disk]->bi_private)->idx < RESYNC_PAGES);
> + } while (page_idx++ < RESYNC_PAGES);
I think you want ++page_idx < RESYNC_PAGES, otherwise there will be
one pass through the loop where page_idx == RESYNC_PAGES
>
> r1_bio->sectors = nr_sectors;
>
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index 5026e7ad51d3..e594ca610f27 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -221,7 +221,6 @@ static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
> resync_get_all_pages(rp);
> }
>
> - rp->idx = 0;
> rp->raid_bio = r10_bio;
> bio->bi_private = rp;
> if (rbio) {
> @@ -2853,6 +2852,7 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
> sector_t sectors_skipped = 0;
> int chunks_skipped = 0;
> sector_t chunk_mask = conf->geo.chunk_mask;
> + int page_idx = 0;
>
> if (!conf->r10buf_pool)
> if (init_resync(conf))
> @@ -3355,7 +3355,7 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
> break;
> for (bio= biolist ; bio ; bio=bio->bi_next) {
> struct resync_pages *rp = get_resync_pages(bio);
> - page = resync_fetch_page(rp, rp->idx++);
> + page = resync_fetch_page(rp, page_idx);
> /*
> * won't fail because the vec table is big enough
> * to hold all these pages
> @@ -3364,7 +3364,7 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
> }
> nr_sectors += len>>9;
> sector_nr += len>>9;
> - } while (get_resync_pages(biolist)->idx < RESYNC_PAGES);
> + } while (page_idx++ < RESYNC_PAGES);
Same problem here.
Otherwise, the patch looks good.
NeilBrown
> r10_bio->sectors = nr_sectors;
>
> while (biolist) {
> --
> 2.9.4
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