1 files changed, 10 insertions, 2 deletions

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 3dc00f0ca8a0..6186f4d7b119 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -411,7 +411,7 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev * dev, int max
 {
         struct pci_bus *child;
         int is_cardbus = (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS);
-        u32 buses;
+        u32 buses, i;
         u16 bctl;
 
         pci_read_config_dword(dev, PCI_PRIMARY_BUS, &buses);
@@ -470,6 +470,10 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev * dev, int max
                 /* Clear errors */
                 pci_write_config_word(dev, PCI_STATUS, 0xffff);
 
+                /* Prevent assigning a bus number that already exists.
+                 * This can happen when a bridge is hot-plugged */
+                if (pci_find_bus(pci_domain_nr(bus), max+1))
+                        return max;
                 child = pci_alloc_child_bus(bus, dev, ++max);
                 buses = (buses & 0xff000000)
                       | ((unsigned int)(child->primary)     <<  0)
@@ -501,7 +505,11 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev * dev, int max
                          * as cards with a PCI-to-PCI bridge can be
                          * inserted later.
                          */
-                        max += CARDBUS_RESERVE_BUSNR;
+                        for (i=0; i<CARDBUS_RESERVE_BUSNR; i++)
+                                if (pci_find_bus(pci_domain_nr(bus),
+                                                        max+i+1))
+                                        break;
+                        max += i;
                 }
                 /*
                  * Set the subordinate bus number to its real value.