Subject: Re: [PATCH] ocxl: Clarify error path in setup_xsl_irq()

From: Frederic Barrat <[email-masked]>
Date: Mon, 10 Dec 2018 18:18:08 +0100

Le 10/12/2018 à 16:18, Greg Kurz a écrit :
> Implementing rollback with goto and labels is a common practice that
> leads to prettier and more maintainable code. FWIW, this design pattern
> is already being used in alloc_link() a few lines below in this file.
> 
> Do the same in setup_xsl_irq().
> 
> Signed-off-by: Greg Kurz <[email-masked]>
> ---

This looks good. I don't have a fixed limit when I start using the "goto 
undo" pattern, so it's likely inconsistent in other places as well. 
Truth is I'm not too fussed either way.

Acked-by: Frederic Barrat <[email-masked]>

>   drivers/misc/ocxl/link.c |   23 ++++++++++++++---------
>   1 file changed, 14 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
> index eed92055184d..659977a17405 100644
> --- a/drivers/misc/ocxl/link.c
> +++ b/drivers/misc/ocxl/link.c
> @@ -273,9 +273,9 @@ static int setup_xsl_irq(struct pci_dev *dev, struct link *link)
>   	spa->irq_name = kasprintf(GFP_KERNEL, "ocxl-xsl-%x-%x-%x",
>   				link->domain, link->bus, link->dev);
>   	if (!spa->irq_name) {
> -		unmap_irq_registers(spa);
>   		dev_err(&dev->dev, "Can't allocate name for xsl interrupt\n");
> -		return -ENOMEM;
> +		rc = -ENOMEM;
> +		goto err_xsl;
>   	}
>   	/*
>   	 * At some point, we'll need to look into allowing a higher
> @@ -283,11 +283,10 @@ static int setup_xsl_irq(struct pci_dev *dev, struct link *link)
>   	 */
>   	spa->virq = irq_create_mapping(NULL, hwirq);
>   	if (!spa->virq) {
> -		kfree(spa->irq_name);
> -		unmap_irq_registers(spa);
>   		dev_err(&dev->dev,
>   			"irq_create_mapping failed for translation interrupt\n");
> -		return -EINVAL;
> +		rc = -EINVAL;
> +		goto err_name;
>   	}
> 
>   	dev_dbg(&dev->dev, "hwirq %d mapped to virq %d\n", hwirq, spa->virq);
> @@ -295,15 +294,21 @@ static int setup_xsl_irq(struct pci_dev *dev, struct link *link)
>   	rc = request_irq(spa->virq, xsl_fault_handler, 0, spa->irq_name,
>   			link);
>   	if (rc) {
> -		irq_dispose_mapping(spa->virq);
> -		kfree(spa->irq_name);
> -		unmap_irq_registers(spa);
>   		dev_err(&dev->dev,
>   			"request_irq failed for translation interrupt: %d\n",
>   			rc);
> -		return -EINVAL;
> +		rc = -EINVAL;
> +		goto err_mapping;
>   	}
>   	return 0;
> +
> +err_mapping:
> +	irq_dispose_mapping(spa->virq);
> +err_name:
> +	kfree(spa->irq_name);
> +err_xsl:
> +	unmap_irq_registers(spa);
> +	return rc;
>   }
> 
>   static void release_xsl_irq(struct link *link)
>