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authorMika Westerberg <mika.westerberg@linux.intel.com>2017-10-13 21:35:43 +0300
committerBjorn Helgaas <bhelgaas@google.com>2017-11-06 18:48:59 -0600
commita20c7f36bd3d20d245616ae223bb9d05dfb6f050 (patch)
parent4147c2fd9b12ae1e0bdbb2dbb9a9163c94a10a22 (diff)
PCI: Do not allocate more buses than available in parent
One can ask more buses to be reserved for hotplug bridges by passing pci=hpbussize=N in the kernel command line. If the parent bus does not have enough bus space available we incorrectly create child bus with the requested number of subordinate buses. In the example below hpbussize is set to one more than we have available buses in the root port: pci 0000:07:00.0: [8086:1578] type 01 class 0x060400 pci 0000:07:00.0: scanning [bus 00-00] behind bridge, pass 0 pci 0000:07:00.0: bridge configuration invalid ([bus 00-00]), reconfiguring pci 0000:07:00.0: scanning [bus 00-00] behind bridge, pass 1 pci_bus 0000:08: busn_res: can not insert [bus 08-ff] under [bus 07-3f] (conflicts with (null) [bus 07-3f]) pci_bus 0000:08: scanning bus ... pci_bus 0000:0a: bus scan returning with max=40 pci_bus 0000:0a: busn_res: [bus 0a-ff] end is updated to 40 pci_bus 0000:0a: [bus 0a-40] partially hidden behind bridge 0000:07 [bus 07-3f] pci_bus 0000:08: bus scan returning with max=40 pci_bus 0000:08: busn_res: [bus 08-ff] end is updated to 40 Instead of allowing this, limit the subordinate number to be less than or equal the maximum subordinate number allocated for the parent bus (if it has any). Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> [bhelgaas: remove irrelevant dmesg messages] Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 61813938d186..1f82f49c0bb3 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1076,7 +1076,8 @@ int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass)
child = pci_add_new_bus(bus, dev, max+1);
if (!child)
goto out;
- pci_bus_insert_busn_res(child, max+1, 0xff);
+ pci_bus_insert_busn_res(child, max+1,
+ bus->busn_res.end);
buses = (buses & 0xff000000)
@@ -2439,6 +2440,10 @@ unsigned int pci_scan_child_bus(struct pci_bus *bus)
if (bus->self && bus->self->is_hotplug_bridge && pci_hotplug_bus_size) {
if (max - bus->busn_res.start < pci_hotplug_bus_size - 1)
max = bus->busn_res.start + pci_hotplug_bus_size - 1;
+ /* Do not allocate more buses than we have room left */
+ if (max > bus->busn_res.end)
+ max = bus->busn_res.end;