From: David Daney Date: Thu, 10 May 2018 19:32:00 +0000 (+0200) Subject: PCI: Avoid bus reset if bridge itself is broken X-Git-Tag: Ubuntu-4.13.0-45.50~35 X-Git-Url: https://git.proxmox.com/?p=mirror_ubuntu-artful-kernel.git;a=commitdiff_plain;h=434e9e87d3150584d269784501e37eecacbb527a PCI: Avoid bus reset if bridge itself is broken 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. BugLink: https://launchpad.net/bugs/1770254 Signed-off-by: David Daney [jglauber@cavium.com: fixed typo] Signed-off-by: Jan Glauber Signed-off-by: Bjorn Helgaas Reviewed-by: Alex Williamson (cherry picked from commit 357027786f3523d26f42391aa4c075b8495e5d28) Signed-off-by: Manoj Iyer Acked-by: Kleber Sacilotto de Souza Acked-by: Khalid Elmously Signed-off-by: Kleber Sacilotto de Souza --- diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 7bb3332310ed..02e844c1e637 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4379,6 +4379,10 @@ static bool pci_bus_resetable(struct pci_bus *bus) { 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)))