Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit ac57cd5e authored by Bjorn Helgaas's avatar Bjorn Helgaas Committed by Jesse Barnes
Browse files

Revert "PCI: fix pci_bus_alloc_resource() hang, prefer positive decode" 



This reverts commit 82e3e767.

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: default avatarH. Peter Anvin <hpa@zytor.com>
Signed-off-by: default avatarBjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
parent 49c2fa08

drivers/pci/bus.c

+21 −49
Original line number Diff line number Diff line
@@ -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;