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/m68k/coldfire/pci.c b/arch/m68k/coldfire/pci.c
index df9679238b6d..821de928dc3f 100644
--- a/arch/m68k/coldfire/pci.c
+++ b/arch/m68k/coldfire/pci.c
@@ -313,12 +313,16 @@ static int __init mcf_pci_init(void)
         schedule_timeout(msecs_to_jiffies(200));
 
         rootbus = pci_scan_bus(0, &mcf_pci_ops, NULL);
+        if (!rootbus)
+                return -ENODEV;
+
         rootbus->resource[0] = &mcf_pci_io;
         rootbus->resource[1] = &mcf_pci_mem;
 
         pci_fixup_irqs(pci_common_swizzle, mcf_pci_map_irq);
         pci_bus_size_bridges(rootbus);
         pci_bus_assign_resources(rootbus);
+        pci_bus_add_devices(rootbus);
         return 0;
 }