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SubjectRe: [PATCH v3 3/4] base/platform: Continue on insert_resource() error
On Wed, Apr 22, 2015 at 06:14:20PM +0200, Ricardo Ribalda Delgado wrote:
> insert_resource() can fail when the resource added overlaps
> (partially or fully) with another.
>
> Device tree and AMBA devices may contain resources that overlap, so they
> could not call platform_device_add (Revert "of: use platform_device_add"
> 02bbde7849e68e193cefaa1885fe0df0f03c9fcd )

Usual style for referencing a commit is "(see 02bbde7849e6 ('Revert "of:
use platform_device_add"'))".

> On the other hand, device trees are released using
> platform_device_unregister(). This function calls platform_device_del(),
> which calls release_resource(), that crashes when the resource has not
> been added with with insert_resource. This was not an issue when the
> device tree could not be modified online, but this is not the case
> anymore.
>
> This patch let the flow continue when there is an insert error, after
> notifying the user with a dev_err(). r->parent is set to NULL, so the
> device_del knows that the resource was not added, and therefore it
> should not be released.

I think you meant platform_device_del()? I don't think device_del() does
anything with resources.

> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
> ---
> drivers/base/platform.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> index 6028681..8cce2a3 100644
> --- a/drivers/base/platform.c
> +++ b/drivers/base/platform.c
> @@ -359,8 +359,7 @@ int platform_device_add(struct platform_device *pdev)
>
> if (insert_resource(p, r)) {
> dev_err(&pdev->dev, "failed to claim resource %d\n", i);

Sounds like we should expect to see this message more in the future, after
you change of_platform_device_create_pdata() use platform_device_add().
You might want to use insert_resource_conflict() here so you can include
information about *why* we failed to claim the resource. And it would be
nice to use %pR for both resources.

> - ret = -EBUSY;
> - goto failed;
> + r->parent = NULL;
> }
> }
>
> @@ -371,7 +370,6 @@ int platform_device_add(struct platform_device *pdev)
> if (ret == 0)
> return ret;
>
> - failed:

Might be nice to keep a comment here as a clue that the rest of the
function is the failure path.

It's a minor style thing, but I would also remove the "err_out" label and
return "ret" directly above rather than branching to "err_out".

> if (pdev->id_auto) {
> ida_simple_remove(&platform_devid_ida, pdev->id);
> pdev->id = PLATFORM_DEVID_AUTO;
> @@ -381,7 +379,8 @@ int platform_device_add(struct platform_device *pdev)
> struct resource *r = &pdev->resource[i];
> unsigned long type = resource_type(r);
>
> - if (type == IORESOURCE_MEM || type == IORESOURCE_IO)
> + if ((type == IORESOURCE_MEM || type == IORESOURCE_IO) &&
> + r->parent)
> release_resource(r);
> }
>
> @@ -414,7 +413,8 @@ void platform_device_del(struct platform_device *pdev)
> struct resource *r = &pdev->resource[i];
> unsigned long type = resource_type(r);
>
> - if (type == IORESOURCE_MEM || type == IORESOURCE_IO)
> + if ((type == IORESOURCE_MEM || type == IORESOURCE_IO) &&
> + r->parent)
> release_resource(r);
> }
> }
> --
> 2.1.4
>


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