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![Lukas Wunner](/assets/img/avatar_default.png)
Upon removal of the last device on a bus, the link_state of the bridge leading to that bus is sought to be torn down by having pci_stop_dev() call pcie_aspm_exit_link_state(). When ASPM was originally introduced by commit7d715a6c1a
("PCI: add PCI Express ASPM support"), it determined whether the device being removed is the last one by calling list_empty() on the bridge's subordinate devices list. That didn't work because the device is only removed from the list slightly later in pci_destroy_dev(). Commit3419c75e15
("PCI: properly clean up ASPM link state on device remove") attempted to fix it by calling list_is_last(), but that's not correct either because it checks whether the device is at the *end* of the list, not whether it's the last one *left* in the list. If the user removes the device which happens to be at the end of the list via sysfs but other devices are preceding the device in the list, the link_state is torn down prematurely. The real fix is to move the invocation of pcie_aspm_exit_link_state() to pci_destroy_dev() and reinstate the call to list_empty(). Remove a duplicate check for dev->bus->self because pcie_aspm_exit_link_state() already contains an identical check. Fixes:7d715a6c1a
("PCI: add PCI Express ASPM support") Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Shaohua Li <shaohua.li@intel.com> Cc: stable@vger.kernel.org # v2.6.26
165 lines
3.7 KiB
C
165 lines
3.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/pci.h>
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#include <linux/module.h>
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#include "pci.h"
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static void pci_free_resources(struct pci_dev *dev)
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{
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int i;
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for (i = 0; i < PCI_NUM_RESOURCES; i++) {
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struct resource *res = dev->resource + i;
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if (res->parent)
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release_resource(res);
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}
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}
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static void pci_stop_dev(struct pci_dev *dev)
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{
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pci_pme_active(dev, false);
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if (pci_dev_is_added(dev)) {
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device_release_driver(&dev->dev);
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pci_proc_detach_device(dev);
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pci_remove_sysfs_dev_files(dev);
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pci_dev_assign_added(dev, false);
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}
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}
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static void pci_destroy_dev(struct pci_dev *dev)
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{
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if (!dev->dev.kobj.parent)
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return;
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device_del(&dev->dev);
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down_write(&pci_bus_sem);
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list_del(&dev->bus_list);
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up_write(&pci_bus_sem);
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pcie_aspm_exit_link_state(dev);
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pci_bridge_d3_update(dev);
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pci_free_resources(dev);
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put_device(&dev->dev);
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}
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void pci_remove_bus(struct pci_bus *bus)
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{
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pci_proc_detach_bus(bus);
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down_write(&pci_bus_sem);
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list_del(&bus->node);
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pci_bus_release_busn_res(bus);
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up_write(&pci_bus_sem);
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pci_remove_legacy_files(bus);
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if (bus->ops->remove_bus)
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bus->ops->remove_bus(bus);
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pcibios_remove_bus(bus);
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device_unregister(&bus->dev);
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}
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EXPORT_SYMBOL(pci_remove_bus);
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static void pci_stop_bus_device(struct pci_dev *dev)
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{
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struct pci_bus *bus = dev->subordinate;
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struct pci_dev *child, *tmp;
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/*
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* Stopping an SR-IOV PF device removes all the associated VFs,
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* which will update the bus->devices list and confuse the
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* iterator. Therefore, iterate in reverse so we remove the VFs
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* first, then the PF.
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*/
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if (bus) {
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list_for_each_entry_safe_reverse(child, tmp,
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&bus->devices, bus_list)
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pci_stop_bus_device(child);
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}
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pci_stop_dev(dev);
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}
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static void pci_remove_bus_device(struct pci_dev *dev)
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{
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struct pci_bus *bus = dev->subordinate;
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struct pci_dev *child, *tmp;
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if (bus) {
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list_for_each_entry_safe(child, tmp,
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&bus->devices, bus_list)
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pci_remove_bus_device(child);
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pci_remove_bus(bus);
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dev->subordinate = NULL;
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}
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pci_destroy_dev(dev);
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}
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/**
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* pci_stop_and_remove_bus_device - remove a PCI device and any children
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* @dev: the device to remove
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*
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* Remove a PCI device from the device lists, informing the drivers
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* that the device has been removed. We also remove any subordinate
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* buses and children in a depth-first manner.
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*
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* For each device we remove, delete the device structure from the
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* device lists, remove the /proc entry, and notify userspace
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* (/sbin/hotplug).
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*/
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void pci_stop_and_remove_bus_device(struct pci_dev *dev)
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{
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pci_stop_bus_device(dev);
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pci_remove_bus_device(dev);
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}
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EXPORT_SYMBOL(pci_stop_and_remove_bus_device);
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void pci_stop_and_remove_bus_device_locked(struct pci_dev *dev)
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{
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pci_lock_rescan_remove();
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pci_stop_and_remove_bus_device(dev);
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pci_unlock_rescan_remove();
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}
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EXPORT_SYMBOL_GPL(pci_stop_and_remove_bus_device_locked);
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void pci_stop_root_bus(struct pci_bus *bus)
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{
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struct pci_dev *child, *tmp;
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struct pci_host_bridge *host_bridge;
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if (!pci_is_root_bus(bus))
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return;
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host_bridge = to_pci_host_bridge(bus->bridge);
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list_for_each_entry_safe_reverse(child, tmp,
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&bus->devices, bus_list)
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pci_stop_bus_device(child);
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/* stop the host bridge */
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device_release_driver(&host_bridge->dev);
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}
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EXPORT_SYMBOL_GPL(pci_stop_root_bus);
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void pci_remove_root_bus(struct pci_bus *bus)
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{
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struct pci_dev *child, *tmp;
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struct pci_host_bridge *host_bridge;
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if (!pci_is_root_bus(bus))
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return;
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host_bridge = to_pci_host_bridge(bus->bridge);
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list_for_each_entry_safe(child, tmp,
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&bus->devices, bus_list)
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pci_remove_bus_device(child);
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pci_remove_bus(bus);
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host_bridge->bus = NULL;
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/* remove the host bridge */
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device_unregister(&host_bridge->dev);
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}
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EXPORT_SYMBOL_GPL(pci_remove_root_bus);
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