Re: [PATCH] nvme-hwmon: don't return errors from nvme_hwmon_init

[Christoph Hellwig <hch@lst.de>]

On Tue, Oct 18, 2022 at 09:15:08AM -0600, Keith Busch wrote:
> We still need to check for < 0 since nvme_hwmon_init() sends an admin
> command. If the admin command times out, the controller is reset and
> -EINTR is returned, indicating we have to abort initialization. All
> other errors should be ignored, though, since the controller remains
> usable.

So I guess we should just ignore everything but EINTR, e.g.:


diff --git a/drivers/nvme/host/hwmon.c b/drivers/nvme/host/hwmon.c
index 0a586d7129201..aed245678315f 100644
--- a/drivers/nvme/host/hwmon.c
+++ b/drivers/nvme/host/hwmon.c
@@ -230,7 +230,7 @@ int nvme_hwmon_init(struct nvme_ctrl *ctrl)
 
 	data = kzalloc(sizeof(*data), GFP_KERNEL);
 	if (!data)
-		return 0;
+		goto err;
 
 	data->ctrl = ctrl;
 	mutex_init(&data->read_lock);
@@ -238,8 +238,7 @@ int nvme_hwmon_init(struct nvme_ctrl *ctrl)
 	err = nvme_hwmon_get_smart_log(data);
 	if (err) {
 		dev_warn(dev, "Failed to read smart log (error %d)\n", err);
-		kfree(data);
-		return err;
+		goto err_free_data;
 	}
 
 	hwmon = hwmon_device_register_with_info(dev, "nvme",
@@ -247,11 +246,22 @@ int nvme_hwmon_init(struct nvme_ctrl *ctrl)
 						NULL);
 	if (IS_ERR(hwmon)) {
 		dev_warn(dev, "Failed to instantiate hwmon device\n");
-		kfree(data);
-		return PTR_ERR(hwmon);
+		err = PTR_ERR(hwmon);
+		goto err_free_data;
 	}
 	ctrl->hwmon_device = hwmon;
 	return 0;
+
+err_free_data:
+	kfree(data);
+err:
+	/*
+	 * Do not return errors unless we are in a controller reset.
+	 * The controller works perfectly fine without the hwmon registration.
+	 */
+	if (err == -EINTR)
+		return -EINTR;
+	return 0;
 }
 
 void nvme_hwmon_exit(struct nvme_ctrl *ctrl)
-- 
2.30.2