linux-kernel - Re: [PATCH v4 1/4] base/platform: Only insert MEM and IO resources

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Message-Id: <20150607142616.B21B3C4244B@trevor.secretlab.ca>
Date:	Sun, 07 Jun 2015 15:26:16 +0100
From:	Grant Likely <grant.likely@...aro.org>
To:	Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Rob Herring <robh+dt@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Jakub Sitnicki <jsitnicki@...il.com>,
	Vivek Goyal <vgoyal@...hat.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Jiang Liu <jiang.liu@...ux.intel.com>,
	Mike Travis <travis@....com>,
	Thierry Reding <treding@...dia.com>,
	linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Cc:	Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>
Subject: Re: [PATCH v4 1/4] base/platform: Only insert MEM and IO resources

On Thu, 23 Apr 2015 15:58:11 +0200
, Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>
 wrote:
> platform_device_del only checks the type of the resource in order to
> call release_resource.
> 
> On the other hand, platform_device_add calls insert_resource for any
> resource that has a parent.
> 
> Make both code branches balanced.
> 
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>
> ---
>  drivers/base/platform.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> index ebf034b..6028681 100644
> --- a/drivers/base/platform.c
> +++ b/drivers/base/platform.c
> @@ -341,19 +341,23 @@ int platform_device_add(struct platform_device *pdev)
>  
>  	for (i = 0; i < pdev->num_resources; i++) {
>  		struct resource *p, *r = &pdev->resource[i];
> +		unsigned long type = resource_type(r);
>  
>  		if (r->name == NULL)
>  			r->name = dev_name(&pdev->dev);
>  
> +		if (!(type == IORESOURCE_MEM || type == IORESOURCE_IO))
> +			continue;
> +
>  		p = r->parent;
>  		if (!p) {
> -			if (resource_type(r) == IORESOURCE_MEM)
> +			if (type == IORESOURCE_MEM)
>  				p = &iomem_resource;
> -			else if (resource_type(r) == IORESOURCE_IO)
> +			else if (type == IORESOURCE_IO)
>  				p = &ioport_resource;
>  		}
>  
> -		if (p && insert_resource(p, r)) {
> +		if (insert_resource(p, r)) {
>  			dev_err(&pdev->dev, "failed to claim resource %d\n", i);
>  			ret = -EBUSY;
>  			goto failed;

This patch is correct in that it makes things balanced, but I don't
think it is the right behaviour. I've just posted a patch that does it
the other way around, based on a patch that Pantelis posted doing the
same thing, but without refactoring at the same time.

Instead of filtering out the non-MEM/IO resources, the new code checks
the parent pointer on removal, because that is the safe test of if a
resource has been registered in the first place.

g.
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