nvme: apple: fix device reference counting

Drivers must call nvme_uninit_ctrl after a successful nvme_init_ctrl.
Split the allocation side out to make the error handling boundary easier
to navigate. The apple driver had been doing this wrong, leaking the
controller device memory on a tagset failure.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>

drivers/nvme/host/apple.c

@@ -1388,7 +1388,7 @@ static void devm_apple_nvme_mempool_destroy(void *data)
 	mempool_destroy(data);
 }
 
-static int apple_nvme_probe(struct platform_device *pdev)
+static struct apple_nvme *apple_nvme_alloc(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct apple_nvme *anv;
@@ -1396,7 +1396,7 @@ static int apple_nvme_probe(struct platform_device *pdev)
 
 	anv = devm_kzalloc(dev, sizeof(*anv), GFP_KERNEL);
 	if (!anv)
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
 	anv->dev = get_device(dev);
 	anv->adminq.is_adminq = true;
@@ -1516,10 +1516,26 @@ static int apple_nvme_probe(struct platform_device *pdev)
 		goto put_dev;
 	}
 
+	return anv;
+put_dev:
+	put_device(anv->dev);
+	return ERR_PTR(ret);
+}
+
+static int apple_nvme_probe(struct platform_device *pdev)
+{
+	struct apple_nvme *anv;
+	int ret;
+
+	anv = apple_nvme_alloc(pdev);
+	if (IS_ERR(anv))
+		return PTR_ERR(anv);
+
 	anv->ctrl.admin_q = blk_mq_alloc_queue(&anv->admin_tagset, NULL, NULL);
 	if (IS_ERR(anv->ctrl.admin_q)) {
 		ret = -ENOMEM;
-		goto put_dev;
+		anv->ctrl.admin_q = NULL;
+		goto out_uninit_ctrl;
 	}
 
 	nvme_reset_ctrl(&anv->ctrl);
@@ -1527,8 +1543,9 @@ static int apple_nvme_probe(struct platform_device *pdev)
 
 	return 0;
 
-put_dev:
-	put_device(anv->dev);
+out_uninit_ctrl:
+	nvme_uninit_ctrl(&anv->ctrl);
+	nvme_put_ctrl(&anv->ctrl);
 	return ret;
 }