Revert "lightnvm: prevent bd removal if busy"

Christoph correctly points out that this issue is no different
for other block devices, and poking at cross layer internals
is not the right way to solve it.

This reverts commit bb6aa6f08268bbce4e0185b18cab9e04505d6695.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/lightnvm/core.c

@@ -390,7 +390,6 @@ static void __nvm_remove_target(struct nvm_target *t)
 static int nvm_remove_tgt(struct nvm_dev *dev, struct nvm_ioctl_remove *remove)
 {
 	struct nvm_target *t;
-	struct block_device *bdev;
 
 	mutex_lock(&dev->mlock);
 	t = nvm_find_target(dev, remove->tgtname);
@@ -398,19 +397,6 @@ static int nvm_remove_tgt(struct nvm_dev *dev, struct nvm_ioctl_remove *remove)
 		mutex_unlock(&dev->mlock);
 		return 1;
 	}
-	bdev = bdget_disk(t->disk, 0);
-	if (!bdev) {
-		pr_err("nvm: removal failed, allocating bd failed\n");
-		mutex_unlock(&dev->mlock);
-		return -ENOMEM;
-	}
-	if (bdev->bd_super || bdev->bd_part_count) {
-		pr_err("nvm: removal failed, block device busy\n");
-		bdput(bdev);
-		mutex_unlock(&dev->mlock);
-		return -EBUSY;
-	}
-	bdput(bdev);
 	__nvm_remove_target(t);
 	mutex_unlock(&dev->mlock);