[PATCH v5 16/23] PCI: hotplug: movable BARs: Don't reserve IO/mem bus space

Sergey Miroshnichenko s.miroshnichenko at yadro.com
Sat Aug 17 02:50:54 AEST 2019


A hotplugged bridge with many hotplug-capable ports may request
reserving more IO space than the machine has. This could be overridden
with the "hpiosize=" kernel argument though.

But when BARs are movable, there are no need to reserve space anymore:
new BARs are allocated not from reserved gaps, but via rearranging the
existing BARs. Requesting a precise amount of space for bridge windows
increases the chances of adding the new bridge successfully.

Signed-off-by: Sergey Miroshnichenko <s.miroshnichenko at yadro.com>
---
 drivers/pci/setup-bus.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index c7b7e30c6284..7d64ec8e7088 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1287,7 +1287,7 @@ void __pci_bus_size_bridges(struct pci_bus *bus, struct list_head *realloc_head)
 
 	case PCI_HEADER_TYPE_BRIDGE:
 		pci_bridge_check_ranges(bus);
-		if (bus->self->is_hotplug_bridge) {
+		if (bus->self->is_hotplug_bridge && !pci_movable_bars_enabled()) {
 			additional_io_size  = pci_hotplug_io_size;
 			additional_mem_size = pci_hotplug_mem_size;
 		}
-- 
2.21.0



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