From 82e3e767c21fef2b1b38868e20eb4e470a1e38e3 Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Wed, 10 Nov 2010 10:26:07 -0700 Subject: [PATCH] PCI: fix pci_bus_alloc_resource() hang, prefer positive decode When a PCI bus has two resources with the same start/end, e.g., pci_bus 0000:04: resource 2 [mem 0xd0000000-0xd7ffffff pref] pci_bus 0000:04: resource 7 [mem 0xd0000000-0xd7ffffff] the previous pci_bus_find_resource_prev() implementation would alternate between them forever: pci_bus_find_resource_prev(... [mem 0xd0000000-0xd7ffffff pref]) returns [mem 0xd0000000-0xd7ffffff] pci_bus_find_resource_prev(... [mem 0xd0000000-0xd7ffffff]) returns [mem 0xd0000000-0xd7ffffff pref] pci_bus_find_resource_prev(... [mem 0xd0000000-0xd7ffffff pref]) returns [mem 0xd0000000-0xd7ffffff] ... This happened because there was no ordering between two resources with the same start and end. A resource that had the same start and end as the cursor, but was not itself the cursor, was considered to be before the cursor. This patch fixes the hang by making a fixed ordering between any two resources. In addition, it tries to allocate from positively decoded regions before using any subtractively decoded resources. This means we will use a positive decode region before a subtractive decode one, even if it means using a smaller address. Reference: https://bugzilla.kernel.org/show_bug.cgi?id=22062 Reported-by: Borislav Petkov Tested-by: Borislav Petkov Acked-by: Linus Torvalds Signed-off-by: Bjorn Helgaas Signed-off-by: Jesse Barnes --- Reading git-format-patch failed