On Wed, Nov 19, 2014 at 01:11:41PM +0100, Arnd Bergmann wrote:

On Wednesday 19 November 2014 15:32:49 Yijing Wang wrote:

quoted

Just like pci_scan_bus(), we also should rip out
pci_bus_add_devices() from pci_scan_root_bus().
Lots platforms first call pci_scan_root_bus(), but
after that, they call pci_bus_size_bridges() and
pci_bus_assign_resources(). Place pci_bus_add_devices()
in pci_scan_root_bus() hurts PCI scan logic.

I think we really need to wait for Bjorn to comment on this patch,
as I mentioned the idea behind pci_scan_root_bus() was to integrate
the scanning part, which you now undo, though I can still see this
working out in the long run.

quoted

Should no functional change.

But you are moving the pci_bus_add_devices() later in a couple of
places. While this seems entirely reasonable, I would consider
it a functional change.

quoted

diff --git a/arch/alpha/kernel/pci.c b/arch/alpha/kernel/pci.c
index 076c35c..97f9730 100644
--- a/arch/alpha/kernel/pci.c
+++ b/arch/alpha/kernel/pci.c

@@ -334,6 +334,8 @@ common_init_pci(void)
 
 		bus = pci_scan_root_bus(NULL, next_busno, alpha_mv.pci_ops,
 					hose, &resources);
+		if (bus)
+			pci_bus_add_devices(bus);
 		hose->bus = bus;
 		hose->need_domain_info = need_domain_info;
 		next_busno = bus->busn_res.end + 1;

How about making pci_bus_add_devices() handle a NULL argument to save
the if() here and elsewhere?

Actually, I would stop there if the bus is NULL and start cleaning up. If not,
things are going to blow up three lines down when next_busno is calculated.

Best regards,
Liviu

quoted

diff --git a/arch/mips/pci/pci.c b/arch/mips/pci/pci.c
index 1bf60b1..f083688 100644
--- a/arch/mips/pci/pci.c
+++ b/arch/mips/pci/pci.c

@@ -113,6 +113,7 @@ static void pcibios_scanbus(struct pci_controller *hose)
 		if (!pci_has_flag(PCI_PROBE_ONLY)) {
 			pci_bus_size_bridges(bus);
 			pci_bus_assign_resources(bus);
+			pci_bus_add_devices(bus);
 		}
 	}
 }

This one looks wrong, I think you still want to call pci_bus_add_devices()
even with PCI_PROBE_ONLY set.

quoted

diff --git a/arch/tile/kernel/pci.c b/arch/tile/kernel/pci.c
index 1f80a88..007466e 100644
--- a/arch/tile/kernel/pci.c
+++ b/arch/tile/kernel/pci.c

@@ -308,6 +308,8 @@ int __init pcibios_init(void)
 			pci_add_resource(&resources, &iomem_resource);
 			bus = pci_scan_root_bus(NULL, 0, controller->ops,
 						controller, &resources);
+			if (bus)
+				pci_bus_add_devices(bus);
 			controller->root_bus = bus;
 			controller->last_busno = bus->busn_res.end;
 		}

Should the pci_bus_add_devices come after setting the bus numbers here?

	Arnd

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