From 8066cc86b7aaaf6b4b38a81932459c6450440daa Mon Sep 17 00:00:00 2001 From: Mika Westerberg Date: Mon, 5 Sep 2022 11:02:27 +0300 Subject: PCI: Fix used_buses calculation in pci_scan_child_bus_extend() pci_scan_bridge_extend() returns the subordinate bus number needed to cover all the buses below a bridge. pci_scan_child_bus_extend() computes the number of buses to reserve by comparing that with the current max bus number. Previously it did the subtraction in the wrong order, so 'used_buses' was nonsense. Subtract 'max' from 'cmax' as is done for the similar pci_scan_bridge_extend() call in the following block. Link: https://bugzilla.kernel.org/show_bug.cgi?id=216000 Fixes: 3374c545c27c ("PCI: Account for all bridges on bus when distributing bus numbers") Link: https://lore.kernel.org/r/20220905080232.36087-2-mika.westerberg@linux.intel.com Reported-by: Chris Chiu Tested-by: Chris Chiu Signed-off-by: Mika Westerberg Signed-off-by: Bjorn Helgaas Reviewed-by: Andy Shevchenko --- drivers/pci/probe.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index c5286b027f00..4f940dcd102c 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -2920,8 +2920,8 @@ static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus, * hotplug bridges too much during the second scan below. */ used_buses++; - if (cmax - max > 1) - used_buses += cmax - max - 1; + if (max - cmax > 1) + used_buses += max - cmax - 1; } /* Scan bridges that need to be reconfigured */ -- cgit v1.2.3