PCI: Document reason for using pci_is_root_bus()



Some code assumes "bus->self == NULL" means the bus is a root bus.  This
adds a comment explaining why this is incorrect ("virtual" buses added for
SR-IOV have "bus->self == NULL" but are not root buses).

No functional change.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

parent 2ba29e27

include/linux/pci.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -470,6 +470,10 @@ struct pci_bus {
		/*
		* Returns true if the pci bus is root (behind host-pci bridge),
		* false otherwise
		*
		* Some code assumes that "bus->self == NULL" means that bus is a root bus.
		* This is incorrect because "virtual" buses added for SR-IOV (via
		* virtfn_add_bus()) have "bus->self == NULL" but are not root buses.
		*/
		static inline bool pci_is_root_bus(struct pci_bus *pbus)
		{