linux-kernel - Re: [PATCH v4 2/4] base/platform: Continue on insert

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Message-ID: <CAL_JsqJ63yajAgFtfrehZWaOQFt0_nwGfh-U501needaBhTMqA@mail.gmail.com>
Date:	Wed, 13 May 2015 09:11:32 -0500
From:	Rob Herring <robherring2@...il.com>
To:	Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Grant Likely <grant.likely@...aro.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" <linux-kernel@...r.kernel.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: Re: [PATCH v4 2/4] base/platform: Continue on insert_resource() error

On Thu, Apr 23, 2015 at 8:58 AM, Ricardo Ribalda Delgado
<ricardo.ribalda@...il.com> 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 (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
> platform_device_del() knows that the resource was not added, and
> therefore it should not be released.
>
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>

Acked-by: Rob Herring <robh@...nel.org>

> ---
>  drivers/base/platform.c | 26 +++++++++++++++-----------
>  1 file changed, 15 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> index 6028681..2e7e904 100644
> --- a/drivers/base/platform.c
> +++ b/drivers/base/platform.c
> @@ -332,7 +332,7 @@ int platform_device_add(struct platform_device *pdev)
>                  */
>                 ret = ida_simple_get(&platform_devid_ida, 0, 0, GFP_KERNEL);
>                 if (ret < 0)
> -                       goto err_out;
> +                       return ret;
>                 pdev->id = ret;
>                 pdev->id_auto = true;
>                 dev_set_name(&pdev->dev, "%s.%d.auto", pdev->name, pdev->id);
> @@ -340,7 +340,7 @@ int platform_device_add(struct platform_device *pdev)
>         }
>
>         for (i = 0; i < pdev->num_resources; i++) {
> -               struct resource *p, *r = &pdev->resource[i];
> +               struct resource *conflict, *p, *r = &pdev->resource[i];
>                 unsigned long type = resource_type(r);
>
>                 if (r->name == NULL)
> @@ -357,11 +357,14 @@ int platform_device_add(struct platform_device *pdev)
>                                 p = &ioport_resource;
>                 }
>
> -               if (insert_resource(p, r)) {
> -                       dev_err(&pdev->dev, "failed to claim resource %d\n", i);
> -                       ret = -EBUSY;
> -                       goto failed;
> -               }
> +               conflict = insert_resource_conflict(p, r);
> +               if (!conflict)
> +                       continue;
> +
> +               dev_err(&pdev->dev,
> +                       "ignoring resource %pR (conflicts with %s %pR)\n",
> +                       r, conflict->name, conflict);
> +               p->parent = NULL;
>         }
>
>         pr_debug("Registering platform device '%s'. Parent at %s\n",
> @@ -371,7 +374,7 @@ int platform_device_add(struct platform_device *pdev)
>         if (ret == 0)
>                 return ret;
>
> - failed:
> +       /* Failure path */
>         if (pdev->id_auto) {
>                 ida_simple_remove(&platform_devid_ida, pdev->id);
>                 pdev->id = PLATFORM_DEVID_AUTO;
> @@ -381,11 +384,11 @@ 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);
>         }
>
> - err_out:
>         return ret;
>  }
>  EXPORT_SYMBOL_GPL(platform_device_add);
> @@ -414,7 +417,8 @@ 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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