linux-kernel - [PATCH 2/2] drivercore: Fix unregistration path of platform devices

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Message-Id: <1433686811-12303-3-git-send-email-grant.likely@linaro.org>
Date:	Sun,  7 Jun 2015 15:20:11 +0100
From:	Grant Likely <grant.likely@...aro.org>
To:	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:	Grant Likely <grant.likely@...aro.org>,
	Pantelis Antoniou <pantelis.antoniou@...sulko.com>,
	Wolfram Sang <wsa@...-dreams.de>,
	Rob Herring <robh@...nel.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>
Subject: [PATCH 2/2] drivercore: Fix unregistration path of platform devices

The unregister path of platform_device is broken. On registration, it
will register all resources with either a parent already set, or
type==IORESOURCE_{IO,MEM}. However, on unregister it will release
everything with type==IORESOURCE_{IO,MEM}, but ignore the others. There
are also cases where resources don't get registered in the first place,
like with devices created by of_platform_populate()*.

Fix the unregister path to be symmetrical with the register path by
checking the parent pointer instead of the type field to decide which
resources to unregister. This is safe because the upshot of the
registration path algorithm is that registered resources have a parent
pointer, and non-registered resources do not.

* It can be argued that of_platform_populate() should be registering
  it's resources, and they argument has some merit. However, there are
  quite a few platforms that end up broken if we try to do that due to
  overlapping resources in the device tree. Until that is fixed, we need
  to solve the immediate problem.

Cc: Pantelis Antoniou <pantelis.antoniou@...sulko.com>
Cc: Wolfram Sang <wsa@...-dreams.de>
Cc: Rob Herring <robh@...nel.org>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>
Signed-off-by: Grant Likely <grant.likely@...aro.org>
---
 drivers/base/platform.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index ebf034b97278..7403de94832c 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -375,9 +375,7 @@ int platform_device_add(struct platform_device *pdev)

 	while (--i >= 0) {
 		struct resource *r = &pdev->resource[i];
-		unsigned long type = resource_type(r);
-
-		if (type == IORESOURCE_MEM || type == IORESOURCE_IO)
+		if (r->parent)
 			release_resource(r);
 	}

@@ -408,9 +406,7 @@ void platform_device_del(struct platform_device *pdev)

 		for (i = 0; i < pdev->num_resources; i++) {
 			struct resource *r = &pdev->resource[i];
-			unsigned long type = resource_type(r);
-
-			if (type == IORESOURCE_MEM || type == IORESOURCE_IO)
+			if (r->parent)
 				release_resource(r);
 		}
 	}
-- 
2.1.4

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