PCI: Make rescan bus increase bridge resource size if needed

Current rescan will not touch bridge MMIO and IO.

Try to reuse pci_assign_unassigned_bridge_resources(bridge) to update bridge
resources, if child devices need more resources.

Only do that for bridges whose children are all removed already; i.e. don't
release resources that could already be in use by drivers on child devices.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index a3cd8cad532a..d9723039e99a 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -366,7 +366,10 @@ dev_bus_rescan_store(struct device *dev, struct device_attribute *attr,
 
         if (val) {
                 mutex_lock(&pci_remove_rescan_mutex);
-                pci_rescan_bus(bus);
+                if (!pci_is_root_bus(bus) && list_empty(&bus->devices))
+                        pci_rescan_bus_bridge_resize(bus->self);
+                else
+                        pci_rescan_bus(bus);
                 mutex_unlock(&pci_remove_rescan_mutex);
         }
         return count;