diff --git a/block/blk-map.c b/block/blk-map.c
index 4849fa36161eb697b47b08efa27af085b58bed3c..0f4b4b88181178b0344127df63af79f7d95da915 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -217,6 +217,12 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
 		return PTR_ERR(bio);
 
 	if (bio->bi_size != len) {
+		/*
+		 * Grab an extra reference to this bio, as bio_unmap_user()
+		 * expects to be able to drop it twice as it happens on the
+		 * normal IO completion path
+		 */
+		bio_get(bio);
 		bio_endio(bio, 0);
 		bio_unmap_user(bio);
 		return -EINVAL;
diff --git a/block/genhd.c b/block/genhd.c
index 4e5e7493f6764e8f3a03b62e40bd40b724d15880..27549e470da54d858e3bccd99946e2db2a311fa6 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -768,6 +768,8 @@ static int __init genhd_device_init(void)
 	bdev_map = kobj_map_init(base_probe, &block_class_lock);
 	blk_dev_init();
 
+	register_blkdev(BLOCK_EXT_MAJOR, "blkext");
+
 #ifndef CONFIG_SYSFS_DEPRECATED
 	/* create top-level block dir */
 	block_depr = kobject_create_and_add("block", NULL);
diff --git a/block/ioctl.c b/block/ioctl.c
index c832d639b6e254eb375d9c69504172182ab14c4d..d03985b04d6768bd0966c3c75f27b6a1336ede1b 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -18,7 +18,6 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user
 	struct disk_part_iter piter;
 	long long start, length;
 	int partno;
-	int err;
 
 	if (!capable(CAP_SYS_ADMIN))
 		return -EACCES;
@@ -61,10 +60,10 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user
 			disk_part_iter_exit(&piter);
 
 			/* all seems OK */
-			err = add_partition(disk, partno, start, length,
-					    ADDPART_FLAG_NONE);
+			part = add_partition(disk, partno, start, length,
+					     ADDPART_FLAG_NONE);
 			mutex_unlock(&bdev->bd_mutex);
-			return err;
+			return IS_ERR(part) ? PTR_ERR(part) : 0;
 		case BLKPG_DEL_PARTITION:
 			part = disk_get_part(disk, partno);
 			if (!part)
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index b220c686089d82b5ffc41eada6efd59c7f7ca7e5..2d19f0cc47f272c5ae4f96ee97ea34a1bce5a407 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -338,12 +338,18 @@ static void do_blkif_request(struct request_queue *rq)
 static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
 {
 	struct request_queue *rq;
+	elevator_t *old_e;
 
 	rq = blk_init_queue(do_blkif_request, &blkif_io_lock);
 	if (rq == NULL)
 		return -1;
 
-	elevator_init(rq, "noop");
+	old_e = rq->elevator;
+	if (IS_ERR_VALUE(elevator_init(rq, "noop")))
+		printk(KERN_WARNING
+			"blkfront: Switch elevator failed, use default\n");
+	else
+		elevator_exit(old_e);
 
 	/* Hard sector size and max sectors impersonate the equiv. hardware. */
 	blk_queue_hardsect_size(rq, sector_size);
diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index 633f7a0ebb2cdfb28207cbb9ec14128ede23f59b..6d5b213b8a9b4b6e834ca9be99ae6c15a3dc0d13 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -348,8 +348,8 @@ static ssize_t whole_disk_show(struct device *dev,
 static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
 		   whole_disk_show, NULL);
 
-int add_partition(struct gendisk *disk, int partno,
-		  sector_t start, sector_t len, int flags)
+struct hd_struct *add_partition(struct gendisk *disk, int partno,
+				sector_t start, sector_t len, int flags)
 {
 	struct hd_struct *p;
 	dev_t devt = MKDEV(0, 0);
@@ -361,15 +361,15 @@ int add_partition(struct gendisk *disk, int partno,
 
 	err = disk_expand_part_tbl(disk, partno);
 	if (err)
-		return err;
+		return ERR_PTR(err);
 	ptbl = disk->part_tbl;
 
 	if (ptbl->part[partno])
-		return -EBUSY;
+		return ERR_PTR(-EBUSY);
 
 	p = kzalloc(sizeof(*p), GFP_KERNEL);
 	if (!p)
-		return -ENOMEM;
+		return ERR_PTR(-EBUSY);
 
 	if (!init_part_stats(p)) {
 		err = -ENOMEM;
@@ -395,7 +395,7 @@ int add_partition(struct gendisk *disk, int partno,
 
 	err = blk_alloc_devt(p, &devt);
 	if (err)
-		goto out_free;
+		goto out_free_stats;
 	pdev->devt = devt;
 
 	/* delay uevent until 'holders' subdir is created */
@@ -424,18 +424,20 @@ int add_partition(struct gendisk *disk, int partno,
 	if (!ddev->uevent_suppress)
 		kobject_uevent(&pdev->kobj, KOBJ_ADD);
 
-	return 0;
+	return p;
 
+out_free_stats:
+	free_part_stats(p);
 out_free:
 	kfree(p);
-	return err;
+	return ERR_PTR(err);
 out_del:
 	kobject_put(p->holder_dir);
 	device_del(pdev);
 out_put:
 	put_device(pdev);
 	blk_free_devt(devt);
-	return err;
+	return ERR_PTR(err);
 }
 
 /* Not exported, helper to add_disk(). */
@@ -566,15 +568,16 @@ int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
 			       disk->disk_name, p, (unsigned long long) size);
 			size = get_capacity(disk) - from;
 		}
-		res = add_partition(disk, p, from, size, state->parts[p].flags);
-		if (res) {
-			printk(KERN_ERR " %s: p%d could not be added: %d\n",
-				disk->disk_name, p, -res);
+		part = add_partition(disk, p, from, size,
+				     state->parts[p].flags);
+		if (IS_ERR(part)) {
+			printk(KERN_ERR " %s: p%d could not be added: %ld\n",
+			       disk->disk_name, p, -PTR_ERR(part));
 			continue;
 		}
 #ifdef CONFIG_BLK_DEV_MD
 		if (state->parts[p].flags & ADDPART_FLAG_RAID)
-			md_autodetect_dev(bdev->bd_dev+p);
+			md_autodetect_dev(part_to_dev(part)->devt);
 #endif
 	}
 	kfree(state);
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index e439e6aed832f3fc98b3a7944521f108e5740fbb..3df7742ce2469e4bdc3673ec904b77e9e4eab6f7 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -522,7 +522,9 @@ extern char *disk_name (struct gendisk *hd, int partno, char *buf);
 
 extern int disk_expand_part_tbl(struct gendisk *disk, int target);
 extern int rescan_partitions(struct gendisk *disk, struct block_device *bdev);
-extern int __must_check add_partition(struct gendisk *, int, sector_t, sector_t, int);
+extern struct hd_struct * __must_check add_partition(struct gendisk *disk,
+						     int partno, sector_t start,
+						     sector_t len, int flags);
 extern void delete_partition(struct gendisk *, int);
 extern void printk_all_partitions(void);
 
diff --git a/kernel/relay.c b/kernel/relay.c
index 8d13a7855c0808858c20fd01d6decebc08c8eeaa..32b0befdcb6a6cba585cb555d9db4a87246d9468 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -400,7 +400,7 @@ void relay_reset(struct rchan *chan)
 	}
 
 	mutex_lock(&relay_channels_mutex);
-	for_each_online_cpu(i)
+	for_each_possible_cpu(i)
 		if (chan->buf[i])
 			__relay_reset(chan->buf[i], 0);
 	mutex_unlock(&relay_channels_mutex);
@@ -611,10 +611,9 @@ struct rchan *relay_open(const char *base_filename,
 	return chan;
 
 free_bufs:
-	for_each_online_cpu(i) {
-		if (!chan->buf[i])
-			break;
-		relay_close_buf(chan->buf[i]);
+	for_each_possible_cpu(i) {
+		if (chan->buf[i])
+			relay_close_buf(chan->buf[i]);
 	}
 
 	kref_put(&chan->kref, relay_destroy_channel);