nvme-pci: factor out a nvme_pci_alloc_dev helper

Add a helper that allocates the nvme_dev structure up to the point where
we can call nvme_init_ctrl.  This pairs with the free_ctrl method and can
thus be used to cleanup the teardown path and make it more symmetric.

Note that this now calls nvme_init_ctrl a lot earlier during probing,
which also means the per-controller character device shows up earlier.
Due to the controller state no commnds can be send on it, but it might
make sense to delay the cdev registration until nvme_init_ctrl_finish.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Tested-by Gerd Bayer <gbayer@linxu.ibm.com>

drivers/nvme/host/pci.c

@@ -2777,6 +2777,7 @@ static void nvme_free_tagset(struct nvme_dev *dev)
 	dev->ctrl.tagset = NULL;
 }
 
+/* pairs with nvme_pci_alloc_dev */
 static void nvme_pci_free_ctrl(struct nvme_ctrl *ctrl)
 {
 	struct nvme_dev *dev = to_nvme_dev(ctrl);
@@ -3090,19 +3091,23 @@ static void nvme_async_probe(void *data, async_cookie_t cookie)
 	nvme_put_ctrl(&dev->ctrl);
 }
 
-static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+static struct nvme_dev *nvme_pci_alloc_dev(struct pci_dev *pdev,
+		const struct pci_device_id *id)
 {
-	int node, result = -ENOMEM;
-	struct nvme_dev *dev;
 	unsigned long quirks = id->driver_data;
+	int node = dev_to_node(&pdev->dev);
+	struct nvme_dev *dev;
+	int ret = -ENOMEM;
 
-	node = dev_to_node(&pdev->dev);
 	if (node == NUMA_NO_NODE)
 		set_dev_node(&pdev->dev, first_memory_node);
 
 	dev = kzalloc_node(sizeof(*dev), GFP_KERNEL, node);
 	if (!dev)
-		return -ENOMEM;
+		return NULL;
+	INIT_WORK(&dev->ctrl.reset_work, nvme_reset_work);
+	INIT_WORK(&dev->remove_work, nvme_remove_dead_ctrl_work);
+	mutex_init(&dev->shutdown_lock);
 
 	dev->nr_write_queues = write_queues;
 	dev->nr_poll_queues = poll_queues;
@@ -3110,25 +3115,11 @@ static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	dev->queues = kcalloc_node(dev->nr_allocated_queues,
 			sizeof(struct nvme_queue), GFP_KERNEL, node);
 	if (!dev->queues)
-		goto free;
+		goto out_free_dev;
 
 	dev->dev = get_device(&pdev->dev);
-	pci_set_drvdata(pdev, dev);
-
-	result = nvme_dev_map(dev);
-	if (result)
-		goto put_pci;
-
-	INIT_WORK(&dev->ctrl.reset_work, nvme_reset_work);
-	INIT_WORK(&dev->remove_work, nvme_remove_dead_ctrl_work);
-	mutex_init(&dev->shutdown_lock);
-
-	result = nvme_setup_prp_pools(dev);
-	if (result)
-		goto unmap;
 
 	quirks |= check_vendor_combination_bug(pdev);
-
 	if (!noacpi && acpi_storage_d3(&pdev->dev)) {
 		/*
 		 * Some systems use a bios work around to ask for D3 on
@@ -3138,34 +3129,54 @@ static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 			 "platform quirk: setting simple suspend\n");
 		quirks |= NVME_QUIRK_SIMPLE_SUSPEND;
 	}
+	ret = nvme_init_ctrl(&dev->ctrl, &pdev->dev, &nvme_pci_ctrl_ops,
+			     quirks);
+	if (ret)
+		goto out_put_device;
+	return dev;
 
-	result = nvme_pci_alloc_iod_mempool(dev);
+out_put_device:
+	put_device(dev->dev);
+	kfree(dev->queues);
+out_free_dev:
+	kfree(dev);
+	return ERR_PTR(ret);
+}
+
+static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+	struct nvme_dev *dev;
+	int result = -ENOMEM;
+
+	dev = nvme_pci_alloc_dev(pdev, id);
+	if (!dev)
+		return -ENOMEM;
+
+	result = nvme_dev_map(dev);
 	if (result)
-		goto release_pools;
+		goto out_uninit_ctrl;
 
-	result = nvme_init_ctrl(&dev->ctrl, &pdev->dev, &nvme_pci_ctrl_ops,
-			quirks);
+	result = nvme_setup_prp_pools(dev);
+	if (result)
+		goto out_dev_unmap;
+
+	result = nvme_pci_alloc_iod_mempool(dev);
 	if (result)
-		goto release_mempool;
+		goto out_release_prp_pools;
 
 	dev_info(dev->ctrl.device, "pci function %s\n", dev_name(&pdev->dev));
+	pci_set_drvdata(pdev, dev);
 
 	nvme_reset_ctrl(&dev->ctrl);
 	async_schedule(nvme_async_probe, dev);
-
 	return 0;
 
- release_mempool:
-	mempool_destroy(dev->iod_mempool);
- release_pools:
+out_release_prp_pools:
 	nvme_release_prp_pools(dev);
- unmap:
+out_dev_unmap:
 	nvme_dev_unmap(dev);
- put_pci:
-	put_device(dev->dev);
- free:
-	kfree(dev->queues);
-	kfree(dev);
+out_uninit_ctrl:
+	nvme_uninit_ctrl(&dev->ctrl);
 	return result;
 }