[PATCH] powerpc/pci: reorder pci bus/bridge unregistration during PHB removal

[PATCH] powerpc/pci: reorder pci bus/bridge unregistration during PHB removal

[Tyrel Datwyler]

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")
Cc: stable@vger.kernel.org
Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
---
v2:
 - Included stable kernel list on Cc per comment by mpe

 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 203cbf0..89e2381 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)
-- 
1.7.12.4

Re: [PATCH] powerpc/pci: reorder pci bus/bridge unregistration during PHB removal

[Tyrel Datwyler]

On 07/28/2014 06:44 PM, Michael Ellerman wrote:
> On Mon, 2014-07-28 at 20:48 -0400, Tyrel Datwyler wrote:
>> 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.
>>
>> Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
> 
> That commit went into 3.13, so shouldn't this be CC to stable?

Darn it. Yes, it should.

> 
> And also:
> 
>   Fixes: bcdde7e221a8 ("sysfs: make __sysfs_remove_dir() recursive")
> 
> cheers
> 
> 

Re: [PATCH] powerpc/pci: reorder pci bus/bridge unregistration during PHB removal

[Michael Ellerman]

On Mon, 2014-07-28 at 20:48 -0400, Tyrel Datwyler wrote:
> 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.
> 
> Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>

That commit went into 3.13, so shouldn't this be CC to stable?

And also:

  Fixes: bcdde7e221a8 ("sysfs: make __sysfs_remove_dir() recursive")

cheers

[PATCH] powerpc/pci: reorder pci bus/bridge unregistration during PHB removal

[Tyrel Datwyler]

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.

Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.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 203cbf0..89e2381 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)
-- 
1.7.12.4