4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Daney <david.daney@xxxxxxxxxx> [ Upstream commit 357027786f3523d26f42391aa4c075b8495e5d28 ] When checking to see if a PCI bus can safely be reset, we previously checked to see if any of the children had their PCI_DEV_FLAGS_NO_BUS_RESET flag set. Children marked with that flag are known not to behave well after a bus reset. Some PCIe root port bridges also do not behave well after a bus reset, sometimes causing the devices behind the bridge to become unusable. Add a check for PCI_DEV_FLAGS_NO_BUS_RESET being set in the bridge device to allow these bridges to be flagged, and prevent their secondary buses from being reset. Signed-off-by: David Daney <david.daney@xxxxxxxxxx> [jglauber@xxxxxxxxxx: fixed typo] Signed-off-by: Jan Glauber <jglauber@xxxxxxxxxx> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> Reviewed-by: Alex Williamson <alex.williamson@xxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/pci/pci.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -3850,6 +3850,10 @@ static bool pci_bus_resetable(struct pci { struct pci_dev *dev; + + if (bus->self && (bus->self->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET)) + return false; + list_for_each_entry(dev, &bus->devices, bus_list) { if (dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET || (dev->subordinate && !pci_bus_resetable(dev->subordinate)))