diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 3e45013d9607..3f2da07676e7 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -103,13 +103,23 @@ static inline struct r10bio *get_resync_r10bio(struct bio *bio)
 	return get_resync_pages(bio)->raid_bio;
 }
 
-static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data)
+static inline int calc_r10bio_size(unsigned int raid_disks)
 {
-	struct r10conf *conf = data;
-	int size = offsetof(struct r10bio, devs[conf->geo.raid_disks]);
+	return offsetof(struct r10bio, devs[raid_disks]);
+}
 
-	/* allocate a r10bio with room for raid_disks entries in the
-	 * bios array */
+static mempool_t *create_r10bio_pool(unsigned int raid_disks)
+{
+	int size = calc_r10bio_size(raid_disks);
+
+	return mempool_create_kmalloc_pool(NR_RAID_BIOS, size);
+}
+
+static struct r10bio *alloc_r10bio(unsigned int raid_disks, gfp_t gfp_flags)
+{
+	int size = calc_r10bio_size(raid_disks);
+
+	/* allocate a r10bio sized for current geometry */
 	return kzalloc(size, gfp_flags);
 }
 
@@ -137,7 +147,7 @@ static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
 	int nalloc, nalloc_rp;
 	struct resync_pages *rps;
 
-	r10_bio = r10bio_pool_alloc(gfp_flags, conf);
+	r10_bio = alloc_r10bio(conf->geo.raid_disks, gfp_flags);
 	if (!r10_bio)
 		return NULL;
 
@@ -277,7 +287,7 @@ static void free_r10bio(struct r10bio *r10_bio)
 	struct r10conf *conf = r10_bio->mddev->private;
 
 	put_all_bios(conf, r10_bio);
-	mempool_free(r10_bio, &conf->r10bio_pool);
+	mempool_free(r10_bio, conf->r10bio_pool);
 }
 
 static void put_buf(struct r10bio *r10_bio)
@@ -1492,7 +1502,7 @@ static bool __make_request(struct mddev *mddev, struct bio *bio, int sectors)
 	struct r10conf *conf = mddev->private;
 	struct r10bio *r10_bio;
 
-	r10_bio = mempool_alloc(&conf->r10bio_pool, GFP_NOIO);
+	r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
 
 	r10_bio->master_bio = bio;
 	r10_bio->sectors = sectors;
@@ -1688,7 +1698,7 @@ static int raid10_handle_discard(struct mddev *mddev, struct bio *bio)
 				(last_stripe_index << geo->chunk_shift);
 
 retry_discard:
-	r10_bio = mempool_alloc(&conf->r10bio_pool, GFP_NOIO);
+	r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
 	r10_bio->mddev = mddev;
 	r10_bio->state = 0;
 	r10_bio->sectors = 0;
@@ -3790,7 +3800,7 @@ static void raid10_free_conf(struct r10conf *conf)
 	if (!conf)
 		return;
 
-	mempool_exit(&conf->r10bio_pool);
+	mempool_destroy(conf->r10bio_pool);
 	kfree(conf->mirrors);
 	kfree(conf->mirrors_old);
 	kfree(conf->mirrors_new);
@@ -3837,9 +3847,8 @@ static struct r10conf *setup_conf(struct mddev *mddev)
 
 	conf->geo = geo;
 	conf->copies = copies;
-	err = mempool_init(&conf->r10bio_pool, NR_RAID_BIOS, r10bio_pool_alloc,
-			   rbio_pool_free, conf);
-	if (err)
+	conf->r10bio_pool = create_r10bio_pool(conf->geo.raid_disks);
+	if (!conf->r10bio_pool)
 		goto out;
 
 	err = bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0);
@@ -4333,6 +4342,7 @@ static int raid10_start_reshape(struct mddev *mddev)
 	struct md_rdev *rdev;
 	int spares = 0;
 	int ret;
+	mempool_t *new_pool = NULL;
 
 	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
 		return -EBUSY;
@@ -4369,6 +4379,11 @@ static int raid10_start_reshape(struct mddev *mddev)
 		return -EINVAL;
 
 	conf->offset_diff = min_offset_diff;
+	if (mddev->delta_disks > 0) {
+		new_pool = create_r10bio_pool(new.raid_disks);
+		if (!new_pool)
+			return -ENOMEM;
+	}
 	spin_lock_irq(&conf->device_lock);
 	if (conf->mirrors_new) {
 		memcpy(conf->mirrors_new, conf->mirrors,
@@ -4469,6 +4484,10 @@ static int raid10_start_reshape(struct mddev *mddev)
 	mddev->raid_disks = conf->geo.raid_disks;
 	mddev->reshape_position = conf->reshape_progress;
 	set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
+	if (new_pool) {
+		mempool_destroy(conf->r10bio_pool);
+		conf->r10bio_pool = new_pool;
+	}
 
 	clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
 	clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
@@ -4491,6 +4510,7 @@ static int raid10_start_reshape(struct mddev *mddev)
 	conf->reshape_safe = MaxSector;
 	mddev->reshape_position = MaxSector;
 	spin_unlock_irq(&conf->device_lock);
+	mempool_destroy(new_pool);
 	return ret;
 }
 
diff --git a/drivers/md/raid10.h b/drivers/md/raid10.h
index ec79d87fb92f..b711626a5db7 100644
--- a/drivers/md/raid10.h
+++ b/drivers/md/raid10.h
@@ -87,7 +87,7 @@ struct r10conf {
 						   */
 	wait_queue_head_t	wait_barrier;
 
-	mempool_t		r10bio_pool;
+	mempool_t		*r10bio_pool;
 	mempool_t		r10buf_pool;
 	struct page		*tmppage;
 	struct bio_set		bio_split;