[3.13.y.z extended stable] Patch "powerpc/pci: Reorder pci bus/bridge unregistration during PHB removal" has been added to staging queue

[Kamal Mostafa]

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

    powerpc/pci: Reorder pci bus/bridge unregistration during PHB removal

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

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.7.

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.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 3a3d5946a3ce5c6d9c8d5bdb366ff5dcb12b74d6 Mon Sep 17 00:00:00 2001
From: Tyrel Datwyler <tyreld at linux.vnet.ibm.com>
Date: Tue, 29 Jul 2014 13:48:13 -0400
Subject: powerpc/pci: Reorder pci bus/bridge unregistration during PHB removal

commit 7340056567e32b2c9d3554eb146e1977c93da116 upstream.

Commit bcdde7e made __sysfs_remove_dir() recursive and introduced a BUG_ON
during PHB removal while attempting to delete the power managment attribute
group of the bus. This is a result of tearing the bridge and bus devices down
out of order in remove_phb_dynamic. Since, the the bus resides below the bridge
in the sysfs device tree it should be torn down first.

This patch simply moves the device_unregister call for the PHB bridge device
after the device_unregister call for the PHB bus.

Fixes: bcdde7e221a8 ("sysfs: make __sysfs_remove_dir() recursive")
Signed-off-by: Tyrel Datwyler <tyreld at linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 arch/powerpc/platforms/pseries/pci_dlpar.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/pci_dlpar.c b/arch/powerpc/platforms/pseries/pci_dlpar.c
index efe6137..e68922b 100644
--- a/arch/powerpc/platforms/pseries/pci_dlpar.c
+++ b/arch/powerpc/platforms/pseries/pci_dlpar.c
@@ -118,10 +118,10 @@ int remove_phb_dynamic(struct pci_controller *phb)
 		}
 	}

-	/* Unregister the bridge device from sysfs and remove the PCI bus */
-	device_unregister(b->bridge);
+	/* Remove the PCI bus and unregister the bridge device from sysfs */
 	phb->bus = NULL;
 	pci_remove_bus(b);
+	device_unregister(b->bridge);

 	/* Now release the IO resource */
 	if (res->flags & IORESOURCE_IO)
--
1.9.1