diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index e871846..fb31e5d 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -29,6 +29,7 @@
 #include <linux/module.h>
 #include <linux/seq_file.h>
 #include <linux/ratelimit.h>
+#include <linux/interval_tree_generic.h>
 
 #include <trace/events/block.h>
 
@@ -50,55 +51,71 @@
 
 #include "raid1-10.c"
 
-static int check_and_add_wb(struct md_rdev *rdev, sector_t lo, sector_t hi)
+#define START(node) ((node)->start)
+#define LAST(node) ((node)->last)
+INTERVAL_TREE_DEFINE(struct serial_info, node, sector_t, _subtree_last,
+		     START, LAST, static inline, raid1_rb);
+
+static int check_and_add_serial(struct md_rdev *rdev, struct r1bio *r1_bio,
+				struct serial_info *si, int idx)
 {
-	struct wb_info *wi, *temp_wi;
 	unsigned long flags;
 	int ret = 0;
-	struct mddev *mddev = rdev->mddev;
+	sector_t lo = r1_bio->sector;
+	sector_t hi = lo + r1_bio->sectors;
+	struct serial_in_rdev *serial = &rdev->serial[idx];
 
-	wi = mempool_alloc(mddev->wb_info_pool, GFP_NOIO);
-
-	spin_lock_irqsave(&rdev->wb_list_lock, flags);
-	list_for_each_entry(temp_wi, &rdev->wb_list, list) {
-		/* collision happened */
-		if (hi > temp_wi->lo && lo < temp_wi->hi) {
-			ret = -EBUSY;
-			break;
-		}
+	spin_lock_irqsave(&serial->serial_lock, flags);
+	/* collision happened */
+	if (raid1_rb_iter_first(&serial->serial_rb, lo, hi))
+		ret = -EBUSY;
+	else {
+		si->start = lo;
+		si->last = hi;
+		raid1_rb_insert(si, &serial->serial_rb);
 	}
-
-	if (!ret) {
-		wi->lo = lo;
-		wi->hi = hi;
-		list_add(&wi->list, &rdev->wb_list);
-	} else
-		mempool_free(wi, mddev->wb_info_pool);
-	spin_unlock_irqrestore(&rdev->wb_list_lock, flags);
+	spin_unlock_irqrestore(&serial->serial_lock, flags);
 
 	return ret;
 }
 
-static void remove_wb(struct md_rdev *rdev, sector_t lo, sector_t hi)
+static void wait_for_serialization(struct md_rdev *rdev, struct r1bio *r1_bio)
 {
-	struct wb_info *wi;
+	struct mddev *mddev = rdev->mddev;
+	struct serial_info *si;
+	int idx = sector_to_idx(r1_bio->sector);
+	struct serial_in_rdev *serial = &rdev->serial[idx];
+
+	if (WARN_ON(!mddev->serial_info_pool))
+		return;
+	si = mempool_alloc(mddev->serial_info_pool, GFP_NOIO);
+	wait_event(serial->serial_io_wait,
+		   check_and_add_serial(rdev, r1_bio, si, idx) == 0);
+}
+
+static void remove_serial(struct md_rdev *rdev, sector_t lo, sector_t hi)
+{
+	struct serial_info *si;
 	unsigned long flags;
 	int found = 0;
 	struct mddev *mddev = rdev->mddev;
+	int idx = sector_to_idx(lo);
+	struct serial_in_rdev *serial = &rdev->serial[idx];
 
-	spin_lock_irqsave(&rdev->wb_list_lock, flags);
-	list_for_each_entry(wi, &rdev->wb_list, list)
-		if (hi == wi->hi && lo == wi->lo) {
-			list_del(&wi->list);
-			mempool_free(wi, mddev->wb_info_pool);
+	spin_lock_irqsave(&serial->serial_lock, flags);
+	for (si = raid1_rb_iter_first(&serial->serial_rb, lo, hi);
+	     si; si = raid1_rb_iter_next(si, lo, hi)) {
+		if (si->start == lo && si->last == hi) {
+			raid1_rb_remove(si, &serial->serial_rb);
+			mempool_free(si, mddev->serial_info_pool);
 			found = 1;
 			break;
 		}
-
+	}
 	if (!found)
-		WARN(1, "The write behind IO is not recorded\n");
-	spin_unlock_irqrestore(&rdev->wb_list_lock, flags);
-	wake_up(&rdev->wb_io_wait);
+		WARN(1, "The write IO is not recorded for serialization\n");
+	spin_unlock_irqrestore(&serial->serial_lock, flags);
+	wake_up(&serial->serial_io_wait);
 }
 
 /*
@@ -279,22 +296,17 @@
 static void call_bio_endio(struct r1bio *r1_bio)
 {
 	struct bio *bio = r1_bio->master_bio;
-	struct r1conf *conf = r1_bio->mddev->private;
 
 	if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
 		bio->bi_status = BLK_STS_IOERR;
 
 	bio_endio(bio);
-	/*
-	 * Wake up any possible resync thread that waits for the device
-	 * to go idle.
-	 */
-	allow_barrier(conf, r1_bio->sector);
 }
 
 static void raid_end_bio_io(struct r1bio *r1_bio)
 {
 	struct bio *bio = r1_bio->master_bio;
+	struct r1conf *conf = r1_bio->mddev->private;
 
 	/* if nobody has done the final endio yet, do it now */
 	if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
@@ -305,6 +317,12 @@
 
 		call_bio_endio(r1_bio);
 	}
+	/*
+	 * Wake up any possible resync thread that waits for the device
+	 * to go idle.  All I/Os, even write-behind writes, are done.
+	 */
+	allow_barrier(conf, r1_bio->sector);
+
 	free_r1bio(r1_bio);
 }
 
@@ -430,6 +448,8 @@
 	int mirror = find_bio_disk(r1_bio, bio);
 	struct md_rdev *rdev = conf->mirrors[mirror].rdev;
 	bool discard_error;
+	sector_t lo = r1_bio->sector;
+	sector_t hi = r1_bio->sector + r1_bio->sectors;
 
 	discard_error = bio->bi_status && bio_op(bio) == REQ_OP_DISCARD;
 
@@ -499,12 +519,8 @@
 	}
 
 	if (behind) {
-		if (test_bit(WBCollisionCheck, &rdev->flags)) {
-			sector_t lo = r1_bio->sector;
-			sector_t hi = r1_bio->sector + r1_bio->sectors;
-
-			remove_wb(rdev, lo, hi);
-		}
+		if (test_bit(CollisionCheck, &rdev->flags))
+			remove_serial(rdev, lo, hi);
 		if (test_bit(WriteMostly, &rdev->flags))
 			atomic_dec(&r1_bio->behind_remaining);
 
@@ -527,7 +543,8 @@
 				call_bio_endio(r1_bio);
 			}
 		}
-	}
+	} else if (rdev->mddev->serialize_policy)
+		remove_serial(rdev, lo, hi);
 	if (r1_bio->bios[mirror] == NULL)
 		rdev_dec_pending(rdev, conf->mddev);
 
@@ -769,36 +786,6 @@
 	return best_disk;
 }
 
-static int raid1_congested(struct mddev *mddev, int bits)
-{
-	struct r1conf *conf = mddev->private;
-	int i, ret = 0;
-
-	if ((bits & (1 << WB_async_congested)) &&
-	    conf->pending_count >= max_queued_requests)
-		return 1;
-
-	rcu_read_lock();
-	for (i = 0; i < conf->raid_disks * 2; i++) {
-		struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
-		if (rdev && !test_bit(Faulty, &rdev->flags)) {
-			struct request_queue *q = bdev_get_queue(rdev->bdev);
-
-			BUG_ON(!q);
-
-			/* Note the '|| 1' - when read_balance prefers
-			 * non-congested targets, it can be removed
-			 */
-			if ((bits & (1 << WB_async_congested)) || 1)
-				ret |= bdi_congested(q->backing_dev_info, bits);
-			else
-				ret &= bdi_congested(q->backing_dev_info, bits);
-		}
-	}
-	rcu_read_unlock();
-	return ret;
-}
-
 static void flush_bio_list(struct r1conf *conf, struct bio *bio)
 {
 	/* flush any pending bitmap writes to disk before proceeding w/ I/O */
@@ -817,8 +804,9 @@
 			/* Just ignore it */
 			bio_endio(bio);
 		else
-			generic_make_request(bio);
+			submit_bio_noacct(bio);
 		bio = next;
+		cond_resched();
 	}
 }
 
@@ -1294,7 +1282,7 @@
 		struct bio *split = bio_split(bio, max_sectors,
 					      gfp, &conf->bio_split);
 		bio_chain(split, bio);
-		generic_make_request(bio);
+		submit_bio_noacct(bio);
 		bio = split;
 		r1_bio->master_bio = bio;
 		r1_bio->sectors = max_sectors;
@@ -1320,7 +1308,7 @@
 	        trace_block_bio_remap(read_bio->bi_disk->queue, read_bio,
 				disk_devt(mddev->gendisk), r1_bio->sector);
 
-	generic_make_request(read_bio);
+	submit_bio_noacct(read_bio);
 }
 
 static void raid1_write_request(struct mddev *mddev, struct bio *bio,
@@ -1465,7 +1453,7 @@
 		struct bio *split = bio_split(bio, max_sectors,
 					      GFP_NOIO, &conf->bio_split);
 		bio_chain(split, bio);
-		generic_make_request(bio);
+		submit_bio_noacct(bio);
 		bio = split;
 		r1_bio->master_bio = bio;
 		r1_bio->sectors = max_sectors;
@@ -1478,6 +1466,7 @@
 
 	for (i = 0; i < disks; i++) {
 		struct bio *mbio = NULL;
+		struct md_rdev *rdev = conf->mirrors[i].rdev;
 		if (!r1_bio->bios[i])
 			continue;
 
@@ -1505,18 +1494,12 @@
 			mbio = bio_clone_fast(bio, GFP_NOIO, &mddev->bio_set);
 
 		if (r1_bio->behind_master_bio) {
-			struct md_rdev *rdev = conf->mirrors[i].rdev;
-
-			if (test_bit(WBCollisionCheck, &rdev->flags)) {
-				sector_t lo = r1_bio->sector;
-				sector_t hi = r1_bio->sector + r1_bio->sectors;
-
-				wait_event(rdev->wb_io_wait,
-					   check_and_add_wb(rdev, lo, hi) == 0);
-			}
+			if (test_bit(CollisionCheck, &rdev->flags))
+				wait_for_serialization(rdev, r1_bio);
 			if (test_bit(WriteMostly, &rdev->flags))
 				atomic_inc(&r1_bio->behind_remaining);
-		}
+		} else if (mddev->serialize_policy)
+			wait_for_serialization(rdev, r1_bio);
 
 		r1_bio->bios[i] = mbio;
 
@@ -2227,7 +2210,7 @@
 		atomic_inc(&r1_bio->remaining);
 		md_sync_acct(conf->mirrors[i].rdev->bdev, bio_sectors(wbio));
 
-		generic_make_request(wbio);
+		submit_bio_noacct(wbio);
 	}
 
 	put_sync_write_buf(r1_bio, 1);
@@ -2913,7 +2896,7 @@
 				md_sync_acct_bio(bio, nr_sectors);
 				if (read_targets == 1)
 					bio->bi_opf &= ~MD_FAILFAST;
-				generic_make_request(bio);
+				submit_bio_noacct(bio);
 			}
 		}
 	} else {
@@ -2922,7 +2905,7 @@
 		md_sync_acct_bio(bio, nr_sectors);
 		if (read_targets == 1)
 			bio->bi_opf &= ~MD_FAILFAST;
-		generic_make_request(bio);
+		submit_bio_noacct(bio);
 	}
 	return nr_sectors;
 }
@@ -3383,7 +3366,6 @@
 	.check_reshape	= raid1_reshape,
 	.quiesce	= raid1_quiesce,
 	.takeover	= raid1_takeover,
-	.congested	= raid1_congested,
 };
 
 static int __init raid_init(void)