[PATCH 2/5] powerpc/pci: Don't scan empty slot

[Gavin Shan]

In hotplug case, function pcibios_add_pci_devices() is called to
rescan the specified PCI bus, which possibly doesn't have any child
devices. Access to the PCI bus's child device node will cause kernel
crash without exception. The patch adds conditions to skip scanning
the PCI bus, which doesn't have any child devices, to avoid the kernel
crash.

Signed-off-by: Gavin Shan <gwshan at linux.vnet.ibm.com>
---
 arch/powerpc/kernel/pci-hotplug.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/pci-hotplug.c b/arch/powerpc/kernel/pci-hotplug.c
index 6e2b4e3..270a26d 100644
--- a/arch/powerpc/kernel/pci-hotplug.c
+++ b/arch/powerpc/kernel/pci-hotplug.c
@@ -120,7 +120,8 @@ void pcibios_add_pci_devices(struct pci_bus * bus)
 	if (mode == PCI_PROBE_DEVTREE) {
 		/* use ofdt-based probe */
 		of_rescan_bus(dn, bus);
-	} else if (mode == PCI_PROBE_NORMAL) {
+	} else if (mode == PCI_PROBE_NORMAL &&
+		   dn->child && PCI_DN(dn->child)) {
 		/*
 		 * Use legacy probe. In the partial hotplug case, we
 		 * probably have grandchildren devices unplugged. So
-- 
1.8.3.2