md/raid10: switch to use md_account_bio() for io accounting

Make sure that 'active_io' will represent inflight io instead of io that
is dispatching, and io accounting from all levels will be consistent.

Signed-off-by: Yu Kuai <[e-mail]>
Reviewed-by: Xiao Ni <[e-mail]>
Signed-off-by: Song Liu <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/md/raid10.c

···
 	if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
 		bio->bi_status = BLK_STS_IOERR;
 
-	if (r10_bio->start_time)
-		bio_end_io_acct(bio, r10_bio->start_time);
 	bio_endio(bio);
 	/*
 	 * Wake up any possible resync thread that waits for the device
···
 }
 
 static void raid10_read_request(struct mddev *mddev, struct bio *bio,
-				struct r10bio *r10_bio)
+				struct r10bio *r10_bio, bool io_accounting)
 {
 	struct r10conf *conf = mddev->private;
 	struct bio *read_bio;
···
 	}
 	slot = r10_bio->read_slot;
 
-	if (!r10_bio->start_time &&
-	    blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
-		r10_bio->start_time = bio_start_io_acct(bio);
+	if (io_accounting) {
+		md_account_bio(mddev, &bio);
+		r10_bio->master_bio = bio;
+	}
 	read_bio = bio_alloc_clone(rdev->bdev, bio, gfp, &mddev->bio_set);
 
 	r10_bio->devs[slot].bio = read_bio;
···
 		r10_bio->master_bio = bio;
 	}
 
-	if (blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
-		r10_bio->start_time = bio_start_io_acct(bio);
+	md_account_bio(mddev, &bio);
+	r10_bio->master_bio = bio;
 	atomic_set(&r10_bio->remaining, 1);
 	md_bitmap_startwrite(mddev->bitmap, r10_bio->sector, r10_bio->sectors, 0);
 
···
 	r10_bio->sector = bio->bi_iter.bi_sector;
 	r10_bio->state = 0;
 	r10_bio->read_slot = -1;
-	r10_bio->start_time = 0;
 	memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) *
 			conf->geo.raid_disks);
 
 	if (bio_data_dir(bio) == READ)
-		raid10_read_request(mddev, bio, r10_bio);
+		raid10_read_request(mddev, bio, r10_bio, true);
 	else
 		raid10_write_request(mddev, bio, r10_bio);
 }
···
 
 	rdev_dec_pending(rdev, mddev);
 	r10_bio->state = 0;
-	raid10_read_request(mddev, r10_bio->master_bio, r10_bio);
+	raid10_read_request(mddev, r10_bio->master_bio, r10_bio, false);
 	/*
 	 * allow_barrier after re-submit to ensure no sync io
 	 * can be issued while regular io pending.

drivers/md/raid10.h

···
 	sector_t		sector;	/* virtual sector number */
 	int			sectors;
 	unsigned long		state;
-	unsigned long		start_time;
 	struct mddev		*mddev;
 	/*
 	 * original bio going to /dev/mdx