From ac57cd5ee1935d1e60de86d75f13f377775f1c96 Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Thu, 16 Dec 2010 10:38:20 -0700 Subject: Revert "PCI: fix pci_bus_alloc_resource() hang, prefer positive decode" This reverts commit 82e3e767c21fef2b1b38868e20eb4e470a1e38e3. We're going back to considering bus resources in the order we found them (in _CRS order, when we're using _CRS), so we don't need to define any ordering. Acked-by: H. Peter Anvin Signed-off-by: Bjorn Helgaas Signed-off-by: Jesse Barnes --- drivers/pci/bus.c | 70 +++++++++++++++++-------------------------------------- 1 file changed, 21 insertions(+), 49 deletions(-) diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c index 003170ea2e39..5624db8c9ad0 100644 --- a/drivers/pci/bus.c +++ b/drivers/pci/bus.c @@ -64,57 +64,17 @@ void pci_bus_remove_resources(struct pci_bus *bus) } } -static bool pci_bus_resource_better(struct resource *res1, bool pos1, - struct resource *res2, bool pos2) -{ - /* If exactly one is positive decode, always prefer that one */ - if (pos1 != pos2) - return pos1 ? true : false; - - /* Prefer the one that contains the highest address */ - if (res1->end != res2->end) - return (res1->end > res2->end) ? true : false; - - /* Otherwise, prefer the one with highest "center of gravity" */ - if (res1->start != res2->start) - return (res1->start > res2->start) ? true : false; - - /* Otherwise, choose one arbitrarily (but consistently) */ - return (res1 > res2) ? true : false; -} - -static bool pci_bus_resource_positive(struct pci_bus *bus, struct resource *res) -{ - struct pci_bus_resource *bus_res; - - /* - * This relies on the fact that pci_bus.resource[] refers to P2P or - * CardBus bridge base/limit registers, which are always positively - * decoded. The pci_bus.resources list contains host bridge or - * subtractively decoded resources. - */ - list_for_each_entry(bus_res, &bus->resources, list) { - if (bus_res->res == res) - return (bus_res->flags & PCI_SUBTRACTIVE_DECODE) ? - false : true; - } - return true; -} - /* - * Find the next-best bus resource after the cursor "res". If the cursor is - * NULL, return the best resource. "Best" means that we prefer positive - * decode regions over subtractive decode, then those at higher addresses. + * Find the highest-address bus resource below the cursor "res". If the + * cursor is NULL, return the highest resource. */ static struct resource *pci_bus_find_resource_prev(struct pci_bus *bus, unsigned int type, struct resource *res) { - bool res_pos, r_pos, prev_pos = false; struct resource *r, *prev = NULL; int i; - res_pos = pci_bus_resource_positive(bus, res); pci_bus_for_each_resource(bus, r, i) { if (!r) continue; @@ -122,14 +82,26 @@ static struct resource *pci_bus_find_resource_prev(struct pci_bus *bus, if ((r->flags & IORESOURCE_TYPE_BITS) != type) continue; - r_pos = pci_bus_resource_positive(bus, r); - if (!res || pci_bus_resource_better(res, res_pos, r, r_pos)) { - if (!prev || pci_bus_resource_better(r, r_pos, - prev, prev_pos)) { - prev = r; - prev_pos = r_pos; - } + /* If this resource is at or past the cursor, skip it */ + if (res) { + if (r == res) + continue; + if (r->end > res->end) + continue; + if (r->end == res->end && r->start > res->start) + continue; } + + if (!prev) + prev = r; + + /* + * A small resource is higher than a large one that ends at + * the same address. + */ + if (r->end > prev->end || + (r->end == prev->end && r->start > prev->start)) + prev = r; } return prev; -- cgit v1.2.3