pci_bridge_d3_update() propagates a bridge_d3 change to upstream bridges by tail recursion: when a bridge's bridge_d3 value changes, the function calls itself with that bridge as the new device.
Convert the tail recursion into an iterative loop. Each level recomputes "remove" and d3cold_ok exactly as the recursive call did for its own device, and the early returns become loop exits. No functional change intended. An upcoming change serializes this update with a mutex; the iterative form lets that mutex be taken once per external call instead of once per bridge level. Assisted-by: LLM Signed-off-by: Pavol Sakac <[email protected]> --- drivers/pci/pci.c | 67 +++++++++++++++++++++++++---------------------- 1 file changed, 35 insertions(+), 32 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index b2879a6be5f8..c62a315c0b4c 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -3104,46 +3104,49 @@ static int pci_dev_check_d3cold(struct pci_dev *dev, void *data) */ void pci_bridge_d3_update(struct pci_dev *dev) { - bool remove = !device_is_registered(&dev->dev); struct pci_dev *bridge; - bool d3cold_ok = true; - bridge = pci_upstream_bridge(dev); - if (!bridge || !pci_bridge_d3_possible(bridge)) - return; + while ((bridge = pci_upstream_bridge(dev)) && + pci_bridge_d3_possible(bridge)) { + bool remove = !device_is_registered(&dev->dev); + bool d3cold_ok = true; - /* - * If D3 is currently allowed for the bridge, removing one of its - * children won't change that. - */ - if (remove && bridge->bridge_d3) - return; + /* + * If D3 is currently allowed for the bridge, removing one of + * its children won't change that. + */ + if (remove && bridge->bridge_d3) + break; - /* - * If D3 is currently allowed for the bridge and a child is added or - * changed, disallowance of D3 can only be caused by that child, so - * we only need to check that single device, not any of its siblings. - * - * If D3 is currently not allowed for the bridge, checking the device - * first may allow us to skip checking its siblings. - */ - if (!remove) - pci_dev_check_d3cold(dev, &d3cold_ok); + /* + * If D3 is currently allowed for the bridge and a child is + * added or changed, disallowance of D3 can only be caused by + * that child, so we only need to check that single device, + * not any of its siblings. + * + * If D3 is currently not allowed for the bridge, checking the + * device first may allow us to skip checking its siblings. + */ + if (!remove) + pci_dev_check_d3cold(dev, &d3cold_ok); - /* - * If D3 is currently not allowed for the bridge, this may be caused - * either by the device being changed/removed or any of its siblings, - * so we need to go through all children to find out if one of them - * continues to block D3. - */ - if (d3cold_ok && !bridge->bridge_d3) - pci_walk_bus(bridge->subordinate, pci_dev_check_d3cold, - &d3cold_ok); + /* + * If D3 is currently not allowed for the bridge, this may be + * caused either by the device being changed/removed or any of + * its siblings, so we need to go through all children to find + * out if one of them continues to block D3. + */ + if (d3cold_ok && !bridge->bridge_d3) + pci_walk_bus(bridge->subordinate, pci_dev_check_d3cold, + &d3cold_ok); + + if (bridge->bridge_d3 == d3cold_ok) + break; - if (bridge->bridge_d3 != d3cold_ok) { bridge->bridge_d3 = d3cold_ok; + /* Propagate change to upstream bridges */ - pci_bridge_d3_update(bridge); + dev = bridge; } } -- 2.47.3
