PCI: Assign resources before drivers claim devices (pci_scan_bus())

Previously, pci_scan_bus() created a root PCI bus, enumerated the devices
on it, and called pci_bus_add_devices(), which made the devices available
for drivers to claim them.

Most callers assigned resources to devices after pci_scan_bus() returns,
which may be after drivers have claimed the devices.  This is incorrect;
the PCI core should not change device resources while a driver is managing
the device.

Remove pci_bus_add_devices() from pci_scan_bus() and do it after any
resource assignment in the callers.

[bhelgaas: changelog, check for failure in mcf_pci_init()]
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Geert Uytterhoeven <geert@linux-m68k.org>
CC: Guan Xuetao <gxt@mprc.pku.edu.cn>
CC: Richard Henderson <rth@twiddle.net>
CC: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
CC: Matt Turner <mattst88@gmail.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/arch/alpha/kernel/sys_nautilus.c b/arch/alpha/kernel/sys_nautilus.c
index 837c0fa..700686d 100644
--- a/arch/alpha/kernel/sys_nautilus.c
+++ b/arch/alpha/kernel/sys_nautilus.c
@@ -207,6 +207,9 @@ nautilus_init_pci(void)
 
 	/* Scan our single hose.  */
 	bus = pci_scan_bus(0, alpha_mv.pci_ops, hose);
+	if (!bus)
+		return;
+
 	hose->bus = bus;
 	pcibios_claim_one_bus(bus);
 
@@ -253,6 +256,7 @@ nautilus_init_pci(void)
 	   for the root bus, so just clear it. */
 	bus->self = NULL;
 	pci_fixup_irqs(alpha_mv.pci_swizzle, alpha_mv.pci_map_irq);
+	pci_bus_add_devices(bus);
 }
 
 /*