pci_bridge_secondary_bus_reset() triggers SBR followed by 1 second sleep, and then uses pci_dev_wait() for waiting device ready. The dev parameter passes to the wait function is currently the bridge itself, but not the device been reset. If we call pci_bridge_secondary_bus_reset() to trigger SBR to a device, there is 1 second sleep but not waiting device ready, since the bridge is always ready while resetting downstream devices. pci_dev_wait() here is a no-op actually. This would be risky in the case which the device becomes ready after more than 1 second, especially while hotplug enabled. The late coming hotplug event after 1 second will trigger hotplug module to remove/re-insert the device. Instead of waiting ready of bridge itself, changing to wait all the downstream devices become ready with timeout PCIE_RESET_READY_POLL_MS after SBR, considering all downstream devices are affected during SBR. Once one of the devices doesn't reappear within the timeout, return -ENOTTY to indicate SBR doesn't complete successfully. Fixes: 6b2f1351af56 ("PCI: Wait for device to become ready after secondary bus reset") Signed-off-by: Sheng Bi <windy.bi.enflame@xxxxxxxxx> --- drivers/pci/pci.c | 30 +++++++++++++++++++++++++++++- 1 file changed, 29 insertions(+), 1 deletion(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index eb7c0a08ff57..4653a9ae6e5b 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5049,6 +5049,34 @@ void pci_bridge_wait_for_secondary_bus(struct pci_dev *dev) } } +static int pci_bridge_secondary_bus_wait(struct pci_dev *bridge, int timeout) +{ + struct pci_dev *dev; + unsigned long start_jiffies; + + down_read(&pci_bus_sem); + + if (!bridge->subordinate || list_empty(&bridge->subordinate->devices)) { + up_read(&pci_bus_sem); + return 0; + } + + list_for_each_entry(dev, &bridge->subordinate->devices, bus_list) { + start_jiffies = jiffies; + + if (timeout < 0 || pci_dev_wait(dev, "bus reset", timeout)) { + up_read(&pci_bus_sem); + return -ENOTTY; + } + + timeout -= jiffies_to_msecs(jiffies - start_jiffies); + } + + up_read(&pci_bus_sem); + + return 0; +} + void pci_reset_secondary_bus(struct pci_dev *dev) { u16 ctrl; @@ -5092,7 +5120,7 @@ int pci_bridge_secondary_bus_reset(struct pci_dev *dev) { pcibios_reset_secondary_bus(dev); - return pci_dev_wait(dev, "bus reset", PCIE_RESET_READY_POLL_MS); + return pci_bridge_secondary_bus_wait(dev, PCIE_RESET_READY_POLL_MS); } EXPORT_SYMBOL_GPL(pci_bridge_secondary_bus_reset); base-commit: 617c8a1e527fadaaec3ba5bafceae7a922ebef7e -- 2.36.1