linux-kernel - Re: [PATCH v3 3/4] cxl/mem: Do not rely on device_add() side effects for dev_set

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Date:   Wed, 31 Mar 2021 10:09:53 -0300
From:   Jason Gunthorpe <jgg@...dia.com>
To:     Dan Williams <dan.j.williams@...el.com>
Cc:     linux-cxl@...r.kernel.org, linux-kernel@...r.kernel.org,
        vishal.l.verma@...el.com, ira.weiny@...el.com,
        alison.schofield@...el.com
Subject: Re: [PATCH v3 3/4] cxl/mem: Do not rely on device_add() side effects
 for dev_set_name() failures

On Tue, Mar 30, 2021 at 04:36:42PM -0700, Dan Williams wrote:
> +static int cxl_mem_add_memdev(struct cxl_mem *cxlm)
> +{
> +	struct cxl_memdev *cxlmd;
> +	struct device *dev;
> +	struct cdev *cdev;
> +	int rc;
> +
> +	cxlmd = cxl_memdev_alloc(cxlm);
> +	if (IS_ERR(cxlmd))
> +		return PTR_ERR(cxlmd);
> +
> +	dev = &cxlmd->dev;
> +	rc = dev_set_name(dev, "mem%d", cxlmd->id);
> +	if (rc)
> +		goto err;
>  
> +	cdev = &cxlmd->cdev;
>  	cxl_memdev_activate(cxlmd, cxlm);
>  	rc = cdev_device_add(cdev, dev);
>  	if (rc)
> -		goto err_add;
> +		goto err;

It might read nicer to have the error unwind here just call cxl_memdev_unregister()

> -	return devm_add_action_or_reset(&pdev->dev, cxl_memdev_unregister,
> +	return devm_add_action_or_reset(dev->parent, cxl_memdev_unregister,
>  					cxlmd);

Since that is what the error unwind does at this point.

>  
> -err_add:
> +err:
>  	/*
>  	 * The cdev was briefly live, shutdown any ioctl operations that
>  	 * saw that state.
>  	 */
>  	cxl_memdev_shutdown(cxlmd);

Then this doesn't need to be a function

But it is OK as is

Reviewed-by: Jason Gunthorpe <jgg@...dia.com>

Jason