md: remove 'idx' from 'struct resync_pages'

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, the current way is wrong since mempool is
only responsible for allocation, we can't use that for initialization.

Suggested-by: NeilBrown <neilb@suse.com>
Reported-by: NeilBrown <neilb@suse.com>
Reported-and-tested-by: Patrick <dto@gmx.net>
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)
Cc: stable@vger.kernel.org (4.12+)
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Shaohua Li <shli@fb.com>

3 files changed, 6 insertions, 7 deletions

diff --git a/drivers/md/md.h b/drivers/md/md.h
index b50eb4ac1b82..991769cc3615 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -738,7 +738,6 @@ 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..0896c772a560 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);
 
         r1_bio->sectors = nr_sectors;
 
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 5026e7ad51d3..fa8bcf04e791 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);
         r10_bio->sectors = nr_sectors;
 
         while (biolist) {