md/raid5: use bio_list for the list of bios to return.

This will make it easier to splice two lists together which will
be needed in future patch.

Signed-off-by: NeilBrown <neilb@suse.com>

2 files changed, 16 insertions, 27 deletions

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 7b0c706f33e7..214dcca0d7f8 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -223,18 +223,14 @@ static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
         return slot;
 }
 
-static void return_io(struct bio *return_bi)
+static void return_io(struct bio_list *return_bi)
 {
-        struct bio *bi = return_bi;
-        while (bi) {
-
-                return_bi = bi->bi_next;
-                bi->bi_next = NULL;
+        struct bio *bi;
+        while ((bi = bio_list_pop(return_bi)) != NULL) {
                 bi->bi_iter.bi_size = 0;
                 trace_block_bio_complete(bdev_get_queue(bi->bi_bdev),
                                          bi, 0);
                 bio_endio(bi, 0);
-                bi = return_bi;
         }
 }
 
@@ -1177,7 +1173,7 @@ async_copy_data(int frombio, struct bio *bio, struct page **page,
 static void ops_complete_biofill(void *stripe_head_ref)
 {
         struct stripe_head *sh = stripe_head_ref;
-        struct bio *return_bi = NULL;
+        struct bio_list return_bi = BIO_EMPTY_LIST;
         int i;
 
         pr_debug("%s: stripe %llu\n", __func__,
@@ -1201,17 +1197,15 @@ static void ops_complete_biofill(void *stripe_head_ref)
                         while (rbi && rbi->bi_iter.bi_sector <
                                 dev->sector + STRIPE_SECTORS) {
                                 rbi2 = r5_next_bio(rbi, dev->sector);
-                                if (!raid5_dec_bi_active_stripes(rbi)) {
-                                        rbi->bi_next = return_bi;
-                                        return_bi = rbi;
-                                }
+                                if (!raid5_dec_bi_active_stripes(rbi))
+                                        bio_list_add(&return_bi, rbi);
                                 rbi = rbi2;
                         }
                 }
         }
         clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
 
-        return_io(return_bi);
+        return_io(&return_bi);
 
         set_bit(STRIPE_HANDLE, &sh->state);
         release_stripe(sh);
@@ -3071,7 +3065,7 @@ static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
 static void
 handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
                                 struct stripe_head_state *s, int disks,
-                                struct bio **return_bi)
+                                struct bio_list *return_bi)
 {
         int i;
         BUG_ON(sh->batch_head);
@@ -3115,8 +3109,7 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
                         clear_bit(BIO_UPTODATE, &bi->bi_flags);
                         if (!raid5_dec_bi_active_stripes(bi)) {
                                 md_write_end(conf->mddev);
-                                bi->bi_next = *return_bi;
-                                *return_bi = bi;
+                                bio_list_add(return_bi, bi);
                         }
                         bi = nextbi;
                 }
@@ -3139,8 +3132,7 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
                         clear_bit(BIO_UPTODATE, &bi->bi_flags);
                         if (!raid5_dec_bi_active_stripes(bi)) {
                                 md_write_end(conf->mddev);
-                                bi->bi_next = *return_bi;
-                                *return_bi = bi;
+                                bio_list_add(return_bi, bi);
                         }
                         bi = bi2;
                 }
@@ -3162,10 +3154,8 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
                                 struct bio *nextbi =
                                         r5_next_bio(bi, sh->dev[i].sector);
                                 clear_bit(BIO_UPTODATE, &bi->bi_flags);
-                                if (!raid5_dec_bi_active_stripes(bi)) {
-                                        bi->bi_next = *return_bi;
-                                        *return_bi = bi;
-                                }
+                                if (!raid5_dec_bi_active_stripes(bi))
+                                        bio_list_add(return_bi, bi);
                                 bi = nextbi;
                         }
                 }
@@ -3444,7 +3434,7 @@ static void break_stripe_batch_list(struct stripe_head *head_sh,
  * never LOCKED, so we don't need to test 'failed' directly.
  */
 static void handle_stripe_clean_event(struct r5conf *conf,
-        struct stripe_head *sh, int disks, struct bio **return_bi)
+        struct stripe_head *sh, int disks, struct bio_list *return_bi)
 {
         int i;
         struct r5dev *dev;
@@ -3478,8 +3468,7 @@ returnbi:
                                         wbi2 = r5_next_bio(wbi, dev->sector);
                                         if (!raid5_dec_bi_active_stripes(wbi)) {
                                                 md_write_end(conf->mddev);
-                                                wbi->bi_next = *return_bi;
-                                                *return_bi = wbi;
+                                                bio_list_add(return_bi, wbi);
                                         }
                                         wbi = wbi2;
                                 }
@@ -4612,7 +4601,7 @@ finish:
                         md_wakeup_thread(conf->mddev->thread);
         }
 
-        return_io(s.return_bi);
+        return_io(&s.return_bi);
 
         clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
 }
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index d05144278690..1de82a6e4c23 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -265,7 +265,7 @@ struct stripe_head_state {
         int dec_preread_active;
         unsigned long ops_request;
 
-        struct bio *return_bi;
+        struct bio_list return_bi;
         struct md_rdev *blocked_rdev;
         int handle_bad_blocks;
 };