lightnvm: if LUNs are already allocated fix return

While creating new device with NVM_DEV_CREATE if LUNs are already
allocated ioctl would return -ENOMEM which is wrong.  This patch
propagates -EBUSY from nvm_reserve_luns which is correct response.

Fixes: ade69e24 ("lightnvm: merge gennvm with core")
Reviewed-by: Frans Klaver <fransklaver@gmail.com>
Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/lightnvm/core.c

@@ -252,8 +252,9 @@ static int nvm_create_tgt(struct nvm_dev *dev, struct nvm_ioctl_create *create)
 	}
 	mutex_unlock(&dev->mlock);
 
-	if (nvm_reserve_luns(dev, s->lun_begin, s->lun_end))
-		return -ENOMEM;
+	ret = nvm_reserve_luns(dev, s->lun_begin, s->lun_end);
+	if (ret)
+		return ret;
 
 	t = kmalloc(sizeof(struct nvm_target), GFP_KERNEL);
 	if (!t) {