linux-kernel - Re: [patch 15/15] PNP: convert resource options to single linked list

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Date:	Tue, 03 Jun 2008 23:13:37 +0200
From:	Rene Herman <rene.herman@...access.nl>
To:	Bjorn Helgaas <bjorn.helgaas@...com>
CC:	Len Brown <lenb@...nel.org>, linux-acpi@...r.kernel.org,
	linux-kernel@...r.kernel.org, Adam Belay <ambx1@....rr.com>,
	Adam M Belay <abelay@....edu>,
	Li Shaohua <shaohua.li@...el.com>,
	Matthieu Castet <castet.matthieu@...e.fr>,
	Thomas Renninger <trenn@...e.de>,
	Jaroslav Kysela <perex@...ex.cz>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Takashi Iwai <tiwai@...e.de>
Subject: Re: [patch 15/15] PNP: convert resource options to single linked
 list

On 31-05-08 00:49, Bjorn Helgaas wrote:

Forgot this comment:

> --- work10.orig/drivers/pnp/quirks.c	2008-05-30 15:58:14.000000000 -0600
> +++ work10/drivers/pnp/quirks.c	2008-05-30 15:58:15.000000000 -0600

> +static struct pnp_option *pnp_clone_dependent_set(struct pnp_dev *dev,
> +						  unsigned int set)
>  {
> -	struct pnp_option *head = NULL;
> -	struct pnp_option *prev = NULL;
> -	struct pnp_option *res;
> -
> -	/*
> -	 * Build a functional IRQ-optional variant of each MPU option.
> -	 */
> -
> -	for (res = dev->dependent; res; res = res->next) {
> -		struct pnp_option *curr;
> -		struct pnp_port *port;
> -		struct pnp_port *copy_port;
> -		struct pnp_irq *irq;
> -		struct pnp_irq *copy_irq;
> -
> -		port = res->port;
> -		irq = res->irq;
> -		if (!port || !irq)
> -			continue;
> +	struct pnp_option *tail = NULL, *first_new_option = NULL;
> +	struct pnp_option *option, *new_option;
> +	unsigned int flags;
> +
> +	list_for_each_entry(option, &dev->options, list) {
> +		if (pnp_option_is_dependent(option))
> +			tail = option;
> +	}
> +	if (!tail) {
> +		dev_err(&dev->dev, "no dependent option sets\n");
> +		return NULL;
> +	}
>  
> -		copy_port = pnp_alloc(sizeof *copy_port);
> -		if (!copy_port)
> -			break;
> -
> -		copy_irq = pnp_alloc(sizeof *copy_irq);
> -		if (!copy_irq) {
> -			kfree(copy_port);
> -			break;
> -		}
> +	flags = pnp_dependent_option(dev, PNP_RES_PRIORITY_FUNCTIONAL);
> +	list_for_each_entry(option, &dev->options, list) {
> +		if (pnp_option_is_dependent(option) &&
> +		    pnp_option_set(option) == set) {
> +			new_option = kmalloc(sizeof(struct pnp_option),
> +					     GFP_KERNEL);
> +			if (!new_option) {
> +				dev_err(&dev->dev, "couldn't clone dependent "
> +					"set %d\n", set);
> +				return NULL;
> +			}
>  
> -		*copy_port = *port;
> -		copy_port->next = NULL;
> +			*new_option = *option;
> +			new_option->flags = flags;
> +			if (!first_new_option)
> +				first_new_option = new_option;
>  
> -		*copy_irq = *irq;
> -		copy_irq->flags |= IORESOURCE_IRQ_OPTIONAL;
> -		copy_irq->next = NULL;
> -
> -		curr = pnp_build_option(PNP_RES_PRIORITY_FUNCTIONAL);
> -		if (!curr) {
> -			kfree(copy_port);
> -			kfree(copy_irq);
> -			break;
> +			list_add(&new_option->list, &tail->list);
> +			tail = new_option;
>  		}
> -		curr->port = copy_port;
> -		curr->irq = copy_irq;
> -
> -		if (prev)
> -			prev->next = curr;
> -		else
> -			head = curr;
> -		prev = curr;
>  	}
> -	if (head)
> -		dev_info(&dev->dev, "adding IRQ-optional MPU options\n");
>  
> -	return head;
> +	return first_new_option;
>  }

This works, but I did the "disconnected chain build" that I did due to 
finding it particularly clumsy to add to the dependent chain while 
walking it.

This avoids actual problems due to num_sets = dev->num_dependents_sets 
in caller and the pnp_option_set(option) == set in the loop (not unlike 
the first version of the original checked for a present irq) but it's 
again checking the options it just added itself.

If you feel that's perfectly fine then <shrug> but thought I'd still 
remark on it in case it wasn't intentional.

Rene.
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