1 files changed, 22 insertions, 15 deletions

diff --git a/block/partitions/core.c b/block/partitions/core.c
index e62a98a8eeb7..722406b841df 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -278,6 +278,15 @@ static void hd_struct_free_work(struct work_struct *work)
 {
 	struct hd_struct *part =
 		container_of(to_rcu_work(work), struct hd_struct, rcu_work);
+	struct gendisk *disk = part_to_disk(part);
+
+	/*
+	 * Release the disk reference acquired in delete_partition here.
+	 * We can't release it in hd_struct_free because the final put_device
+	 * needs process context and thus can't be run directly from a
+	 * percpu_ref ->release handler.
+	 */
+	put_device(disk_to_dev(disk));
 
 	part->start_sect = 0;
 	part->nr_sects = 0;
@@ -293,7 +302,6 @@ static void hd_struct_free(struct percpu_ref *ref)
 		rcu_dereference_protected(disk->part_tbl, 1);
 
 	rcu_assign_pointer(ptbl->last_lookup, NULL);
-	put_device(disk_to_dev(disk));
 
 	INIT_RCU_WORK(&part->rcu_work, hd_struct_free_work);
 	queue_rcu_work(system_wq, &part->rcu_work);
@@ -524,19 +532,20 @@ int bdev_add_partition(struct block_device *bdev, int partno,
 int bdev_del_partition(struct block_device *bdev, int partno)
 {
 	struct block_device *bdevp;
-	struct hd_struct *part;
-	int ret = 0;
+	struct hd_struct *part = NULL;
+	int ret;
 
-	part = disk_get_part(bdev->bd_disk, partno);
-	if (!part)
-		return -ENXIO;
-
-	ret = -ENOMEM;
-	bdevp = bdget(part_devt(part));
+	bdevp = bdget_disk(bdev->bd_disk, partno);
 	if (!bdevp)
-		goto out_put_part;
+		return -ENXIO;
 
 	mutex_lock(&bdevp->bd_mutex);
+	mutex_lock_nested(&bdev->bd_mutex, 1);
+
+	ret = -ENXIO;
+	part = disk_get_part(bdev->bd_disk, partno);
+	if (!part)
+		goto out_unlock;
 
 	ret = -EBUSY;
 	if (bdevp->bd_openers)
@@ -545,16 +554,14 @@ int bdev_del_partition(struct block_device *bdev, int partno)
 	sync_blockdev(bdevp);
 	invalidate_bdev(bdevp);
 
-	mutex_lock_nested(&bdev->bd_mutex, 1);
 	delete_partition(bdev->bd_disk, part);
-	mutex_unlock(&bdev->bd_mutex);
-
 	ret = 0;
 out_unlock:
+	mutex_unlock(&bdev->bd_mutex);
 	mutex_unlock(&bdevp->bd_mutex);
 	bdput(bdevp);
-out_put_part:
-	disk_put_part(part);
+	if (part)
+		disk_put_part(part);
 	return ret;
 }