diff mbox series

[v8,3/6] PCI: Change extend_bridge_window() to set resource size directly

Message ID SL2P216MB018777F9E124D364769E5D4680C00@SL2P216MB0187.KORP216.PROD.OUTLOOK.COM (mailing list archive)
State New, archived
Delegated to: Bjorn Helgaas
Headers show
Series Patch series to support Thunderbolt without any BIOS support | expand

Commit Message

Nicholas Johnson July 26, 2019, 12:54 p.m. UTC
Change extend_bridge_window() to set resource size directly instead of
using additional resource lists.

Because additional resource lists are optional resources, any algorithm
that requires guaranteed allocation that uses them cannot be guaranteed
to work.

Remove the resource from add_list. If it is set to zero size and left,
it can cause significant problems when it comes to assigning resources.

Signed-off-by: Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au>
---
 drivers/pci/setup-bus.c | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

Comments

Mika Westerberg Oct. 8, 2019, 12:05 p.m. UTC | #1
On Fri, Jul 26, 2019 at 12:54:01PM +0000, Nicholas Johnson wrote:
> Change extend_bridge_window() to set resource size directly instead of
> using additional resource lists.
> 
> Because additional resource lists are optional resources, any algorithm
> that requires guaranteed allocation that uses them cannot be guaranteed
> to work.
> 
> Remove the resource from add_list. If it is set to zero size and left,
> it can cause significant problems when it comes to assigning resources.

It would be good if you would open bit more what kind of significant
problems this may result.

> Signed-off-by: Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au>

Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
diff mbox series

Patch

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 3b3055e0e..a072781ab 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1818,7 +1818,7 @@  static void extend_bridge_window(struct pci_dev *bridge, struct resource *res,
 				 struct list_head *add_list,
 				 resource_size_t new_size)
 {
-	struct pci_dev_resource *dev_res;
+	resource_size_t add_size;
 
 	if (res->parent)
 		return;
@@ -1826,17 +1826,10 @@  static void extend_bridge_window(struct pci_dev *bridge, struct resource *res,
 	if (resource_size(res) >= new_size)
 		return;
 
-	dev_res = res_to_dev_res(add_list, res);
-	if (!dev_res)
-		return;
-
-	/* Is there room to extend the window? */
-	if (new_size - resource_size(res) <= dev_res->add_size)
-		return;
-
-	dev_res->add_size = new_size - resource_size(res);
-	pci_dbg(bridge, "bridge window %pR extended by %pa\n", res,
-		&dev_res->add_size);
+	add_size = new_size - resource_size(res);
+	pci_dbg(bridge, "bridge window %pR extended by %pa\n", res, &add_size);
+	res->end = res->start + new_size - 1;
+	remove_from_list(add_list, res);
 }
 
 static void pci_bus_distribute_available_resources(struct pci_bus *bus,