linux/drivers/pci/remove.c

168 lines
3.7 KiB
C
Raw Normal View History

// SPDX-License-Identifier: GPL-2.0
#include <linux/pci.h>
#include <linux/module.h>
#include <linux/pci-aspm.h>
#include "pci.h"
static void pci_free_resources(struct pci_dev *dev)
{
int i;
for (i = 0; i < PCI_NUM_RESOURCES; i++) {
struct resource *res = dev->resource + i;
if (res->parent)
release_resource(res);
}
}
static void pci_stop_dev(struct pci_dev *dev)
{
pci_pme_active(dev, false);
if (dev->is_added) {
device_release_driver(&dev->dev);
pci_proc_detach_device(dev);
pci_remove_sysfs_dev_files(dev);
dev->is_added = 0;
}
if (dev->bus->self)
pcie_aspm_exit_link_state(dev);
}
static void pci_destroy_dev(struct pci_dev *dev)
{
if (!dev->dev.kobj.parent)
return;
PCI: Move device_del() from pci_stop_dev() to pci_destroy_dev() After commit bcdde7e221a8 (sysfs: make __sysfs_remove_dir() recursive) I'm seeing traces analogous to the one below in Thunderbolt testing: WARNING: CPU: 3 PID: 76 at /scratch/rafael/work/linux-pm/fs/sysfs/group.c:214 sysfs_remove_group+0x59/0xe0() sysfs group ffffffff81c6c500 not found for kobject '0000:08' Modules linked in: ... CPU: 3 PID: 76 Comm: kworker/u16:7 Not tainted 3.13.0-rc1+ #76 Hardware name: Acer Aspire S5-391/Venus , BIOS V1.02 05/29/2012 Workqueue: kacpi_hotplug acpi_hotplug_work_fn 0000000000000009 ffff8801644b9ac8 ffffffff816b23bf 0000000000000007 ffff8801644b9b18 ffff8801644b9b08 ffffffff81046607 ffff88016925b800 0000000000000000 ffffffff81c6c500 ffff88016924f928 ffff88016924f800 Call Trace: [<ffffffff816b23bf>] dump_stack+0x4e/0x71 [<ffffffff81046607>] warn_slowpath_common+0x87/0xb0 [<ffffffff810466d1>] warn_slowpath_fmt+0x41/0x50 [<ffffffff811e42ef>] ? sysfs_get_dirent_ns+0x6f/0x80 [<ffffffff811e5389>] sysfs_remove_group+0x59/0xe0 [<ffffffff8149f00b>] dpm_sysfs_remove+0x3b/0x50 [<ffffffff81495818>] device_del+0x58/0x1c0 [<ffffffff814959c8>] device_unregister+0x48/0x60 [<ffffffff813254fe>] pci_remove_bus+0x6e/0x80 [<ffffffff81325548>] pci_remove_bus_device+0x38/0x110 [<ffffffff8132555d>] pci_remove_bus_device+0x4d/0x110 [<ffffffff81325639>] pci_stop_and_remove_bus_device+0x19/0x20 [<ffffffff813418d0>] disable_slot+0x20/0xe0 [<ffffffff81341a38>] acpiphp_check_bridge+0xa8/0xd0 [<ffffffff813427ad>] hotplug_event+0x17d/0x220 [<ffffffff81342880>] hotplug_event_work+0x30/0x70 [<ffffffff8136d665>] acpi_hotplug_work_fn+0x18/0x24 [<ffffffff81061331>] process_one_work+0x261/0x450 [<ffffffff81061a7e>] worker_thread+0x21e/0x370 [<ffffffff81061860>] ? rescuer_thread+0x300/0x300 [<ffffffff81068342>] kthread+0xd2/0xe0 [<ffffffff81068270>] ? flush_kthread_worker+0x70/0x70 [<ffffffff816c19bc>] ret_from_fork+0x7c/0xb0 [<ffffffff81068270>] ? flush_kthread_worker+0x70/0x70 (Mika Westerberg sees them too in his tests). Some investigation documented in kernel bug #65281 led me to the conclusion that the source of the problem is the device_del() in pci_stop_dev() as it now causes the sysfs directory of the device to be removed recursively along with all of its subdirectories. That includes the sysfs directory of the device's subordinate bus (dev->subordinate) and its "power" group. Consequently, when pci_remove_bus() is called for dev->subordinate in pci_remove_bus_device(), it calls device_unregister(&bus->dev), but at this point the sysfs directory of bus->dev doesn't exist any more and its "power" group doesn't exist either. Thus, when dpm_sysfs_remove() called from device_del() tries to remove that group, it triggers the above warning. That indicates a logical mistake in the design of pci_stop_and_remove_bus_device(), which causes bus device objects to be left behind their parents (bridge device objects) and can be fixed by moving the device_del() from pci_stop_dev() into pci_destroy_dev(), so pci_remove_bus() can be called for the device's subordinate bus before the device itself is unregistered from the hierarchy. Still, the driver, if any, should be detached from the device in pci_stop_dev(), so use device_release_driver() directly from there. References: https://bugzilla.kernel.org/show_bug.cgi?id=65281#c6 Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2013-12-18 20:53:32 +00:00
device_del(&dev->dev);
down_write(&pci_bus_sem);
list_del(&dev->bus_list);
up_write(&pci_bus_sem);
pci_bridge_d3_update(dev);
pci_free_resources(dev);
put_device(&dev->dev);
}
void pci_remove_bus(struct pci_bus *bus)
{
pci_proc_detach_bus(bus);
down_write(&pci_bus_sem);
list_del(&bus->node);
pci_bus_release_busn_res(bus);
up_write(&pci_bus_sem);
pci_remove_legacy_files(bus);
if (bus->ops->remove_bus)
bus->ops->remove_bus(bus);
pcibios_remove_bus(bus);
device_unregister(&bus->dev);
}
EXPORT_SYMBOL(pci_remove_bus);
static void pci_stop_bus_device(struct pci_dev *dev)
{
struct pci_bus *bus = dev->subordinate;
struct pci_dev *child, *tmp;
/*
* Stopping an SR-IOV PF device removes all the associated VFs,
* which will update the bus->devices list and confuse the
* iterator. Therefore, iterate in reverse so we remove the VFs
* first, then the PF.
*/
if (bus) {
list_for_each_entry_safe_reverse(child, tmp,
&bus->devices, bus_list)
pci_stop_bus_device(child);
}
pci_stop_dev(dev);
}
static void pci_remove_bus_device(struct pci_dev *dev)
{
struct pci_bus *bus = dev->subordinate;
struct pci_dev *child, *tmp;
if (bus) {
list_for_each_entry_safe(child, tmp,
&bus->devices, bus_list)
pci_remove_bus_device(child);
pci_remove_bus(bus);
dev->subordinate = NULL;
}
pci_destroy_dev(dev);
}
/**
* pci_stop_and_remove_bus_device - remove a PCI device and any children
* @dev: the device to remove
*
* Remove a PCI device from the device lists, informing the drivers
* that the device has been removed. We also remove any subordinate
* buses and children in a depth-first manner.
*
* For each device we remove, delete the device structure from the
* device lists, remove the /proc entry, and notify userspace
* (/sbin/hotplug).
*/
void pci_stop_and_remove_bus_device(struct pci_dev *dev)
{
pci_stop_bus_device(dev);
pci_remove_bus_device(dev);
}
EXPORT_SYMBOL(pci_stop_and_remove_bus_device);
void pci_stop_and_remove_bus_device_locked(struct pci_dev *dev)
{
pci_lock_rescan_remove();
pci_stop_and_remove_bus_device(dev);
pci_unlock_rescan_remove();
}
EXPORT_SYMBOL_GPL(pci_stop_and_remove_bus_device_locked);
void pci_stop_root_bus(struct pci_bus *bus)
{
struct pci_dev *child, *tmp;
struct pci_host_bridge *host_bridge;
if (!pci_is_root_bus(bus))
return;
host_bridge = to_pci_host_bridge(bus->bridge);
list_for_each_entry_safe_reverse(child, tmp,
&bus->devices, bus_list)
pci_stop_bus_device(child);
/* stop the host bridge */
device_release_driver(&host_bridge->dev);
}
EXPORT_SYMBOL_GPL(pci_stop_root_bus);
void pci_remove_root_bus(struct pci_bus *bus)
{
struct pci_dev *child, *tmp;
struct pci_host_bridge *host_bridge;
if (!pci_is_root_bus(bus))
return;
host_bridge = to_pci_host_bridge(bus->bridge);
list_for_each_entry_safe(child, tmp,
&bus->devices, bus_list)
pci_remove_bus_device(child);
pci_remove_bus(bus);
host_bridge->bus = NULL;
/* remove the host bridge */
device_unregister(&host_bridge->dev);
}
EXPORT_SYMBOL_GPL(pci_remove_root_bus);