[3.13.y-ckt stable] Patch "drivercore: Fix unregistration path of platform devices" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    drivercore: Fix unregistration path of platform devices

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt28.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From d9e87bf3c299ded79f2cfafc073c72ba376800b6 Mon Sep 17 00:00:00 2001
From: Grant Likely <grant.likely at linaro.org>
Date: Sun, 7 Jun 2015 15:20:11 +0100
Subject: drivercore: Fix unregistration path of platform devices

commit 7f5dcaf1fdf289767a126a0a5cc3ef39b5254b06 upstream.

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 at konsulko.com>
Cc: Wolfram Sang <wsa at the-dreams.de>
Cc: Rob Herring <robh at kernel.org>
Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Cc: Ricardo Ribalda Delgado <ricardo.ribalda at gmail.com>
Signed-off-by: Grant Likely <grant.likely at linaro.org>
Tested-by: Ricardo Ribalda Delgado <ricardo.ribalda at gmail.com>
Tested-by: Wolfram Sang <wsa+renesas at sang-engineering.com>
Signed-off-by: Rob Herring <robh at kernel.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 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 f081b81..7cc890b 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -362,9 +362,7 @@ 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);
 	}

@@ -395,9 +393,7 @@ 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);
 		}
 	}
--
1.9.1