[PATCH 3.13 151/187] powerpc/pci: Reorder pci bus/bridge unregistration during PHB removal

Kamal Mostafa kamal at canonical.com
Mon Sep 15 22:09:21 UTC 2014 -stable review patch.  If anyone has any objections, please let me know.


From: Tyrel Datwyler <tyreld at linux.vnet.ibm.com>

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;
+	device_unregister(b->bridge);
 	/* Now release the IO resource */
 	if (res->flags & IORESOURCE_IO)

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