[PATCH] PCI: Add pci_walk_bus function to PCI core (nonrecursive)

[PATCH] PCI: Add pci_walk_bus function to PCI core (nonrecursive)

The PCI error recovery infrastructure needs to be able to contact all
the drivers affected by a PCI error event, which may mean traversing
all the devices under a given PCI-PCI bridge.  This patch adds a
function to the PCI core that traverses all the PCI devices on a PCI
bus and under any PCI-PCI bridges on that bus (and so on), calling a
given function for each device.  This provides a way for the error
recovery code to iterate through all devices that are affected by an
error event.

This version is not implemented as a recursive function.  Instead,
when we reach a PCI-PCI bridge, we set the pointers to start doing the
devices on the bus under the bridge, and when we reach the end of a
bus's devices, we use the bus->self pointer to go back up to the next
higher bus and continue doing its devices.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>