linux/drivers/pci
Dan Williams c9d52fb313 PCI: Revert the cfg_access_lock lockdep mechanism
While the experiment did reveal that there are additional places that are
missing the lock during secondary bus reset, one of the places that needs
to take cfg_access_lock (pci_bus_lock()) is not prepared for lockdep
annotation.

Specifically, pci_bus_lock() takes pci_dev_lock() recursively and is
currently dependent on the fact that the device_lock() is marked
lockdep_set_novalidate_class(&dev->mutex). Otherwise, without that
annotation, pci_bus_lock() would need to use something like a new
pci_dev_lock_nested() helper, a scheme to track a PCI device's depth in the
topology, and a hope that the depth of a PCI tree never exceeds the max
value for a lockdep subclass.

The alternative to ripping out the lockdep coverage would be to deploy a
dynamic lock key for every PCI device. Unfortunately, there is evidence
that increasing the number of keys that lockdep needs to track to be
per-PCI-device is prohibitively expensive for something like the
cfg_access_lock.

The main motivation for adding the annotation in the first place was to
catch unlocked secondary bus resets, not necessarily catch lock ordering
problems between cfg_access_lock and other locks. Solve that narrower
problem with follow-on patches, and just due to targeted revert for now.

Link: https://lore.kernel.org/r/171711746402.1628941.14575335981264103013.stgit@dwillia2-xfh.jf.intel.com
Fixes: 7e89efc6e9 ("PCI: Lock upstream bridge for pci_reset_function()")
Reported-by: Imre Deak <imre.deak@intel.com>
Closes: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_134186v1/shard-dg2-1/igt@device_reset@unbind-reset-rebind.html
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Kalle Valo <kvalo@kernel.org>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Cc: Jani Saarinen <jani.saarinen@intel.com>
2024-06-04 12:10:05 -05:00
..
controller Merge branch 'pci/controller/tegra194' 2024-05-16 18:14:13 -05:00
endpoint Merge branch 'pci/endpoint' 2024-05-16 18:14:13 -05:00
hotplug PCI: hotplug: Remove obsolete sgi_hotplug TODO notes 2024-05-03 16:26:50 -05:00
msi Merge branch 'pci/ims-removal' 2024-05-16 18:14:14 -05:00
pcie pci-v6.10-changes 2024-05-21 10:09:28 -07:00
switch PCI: switchtec: Fix an error handling path in switchtec_pci_probe() 2024-02-08 15:35:38 -06:00
access.c PCI: Revert the cfg_access_lock lockdep mechanism 2024-06-04 12:10:05 -05:00
ats.c PCI/ATS: Use FIELD_GET() 2023-10-24 16:55:45 -05:00
bus.c PCI/ASPM: Fix deadlock when enabling ASPM 2024-01-31 09:03:51 -06:00
devres.c PCI: Move devres code from pci.c to devres.c 2024-02-12 10:36:17 -06:00
doe.c PCI/DOE: Support discovery version 2 2024-04-09 09:33:15 -05:00
ecam.c
host-bridge.c
iomap.c PCI: Move pci_iomap.c to drivers/pci/ 2024-02-12 10:35:40 -06:00
iov.c PCI: Use resource names in PCI log messages 2023-12-15 17:28:42 -06:00
irq.c PCI: Place interrupt related code into irq.c 2024-01-29 17:01:31 -06:00
Kconfig PCI: Move pci_iomap.c to drivers/pci/ 2024-02-12 10:35:40 -06:00
Makefile Merge branch 'pci/sysfs' 2024-03-12 12:14:23 -05:00
mmap.c PCI/sysfs: Compile pci-sysfs.c only if CONFIG_SYSFS=y 2024-03-05 16:08:43 -06:00
of_property.c PCI: of_property: Return error for int_map allocation failure 2024-05-02 17:15:01 -05:00
of.c PCI: of: Destroy changeset when adding PCI device node fails 2023-09-29 17:33:51 -05:00
p2pdma.c PCI/P2PDMA: Fix a sleeping issue in a RCU read section 2024-02-08 15:31:43 -06:00
pci-acpi.c Merge branch 'pci/pm' 2023-10-28 13:30:59 -05:00
pci-bridge-emul.c PCI: pci-bridge-emul: Set position of PCI capabilities to real HW value 2022-08-25 12:07:56 +02:00
pci-bridge-emul.h PCI: pci-bridge-emul: Set position of PCI capabilities to real HW value 2022-08-25 12:07:56 +02:00
pci-driver.c Merge branch 'pci/misc' 2024-03-12 12:14:24 -05:00
pci-label.c
pci-mid.c
pci-pf-stub.c
pci-stub.c
pci-sysfs.c PCI/sysfs: Demacrofy pci_dev_resource_resize_attr(n) functions 2024-03-05 16:10:17 -06:00
pci.c PCI: Revert the cfg_access_lock lockdep mechanism 2024-06-04 12:10:05 -05:00
pci.h PCI: Make pcie_bandwidth_capable() static 2024-05-08 19:03:55 -05:00
probe.c PCI: Revert the cfg_access_lock lockdep mechanism 2024-06-04 12:10:05 -05:00
proc.c
quirks.c pci-v6.10-changes 2024-05-21 10:09:28 -07:00
remove.c PCI: Create device tree node for bridge 2023-08-22 14:56:09 -05:00
rom.c
search.c PCI: Add pci_get_base_class() helper 2023-09-28 16:49:44 -05:00
setup-bus.c PCI: Use resource names in PCI log messages 2023-12-15 17:28:42 -06:00
setup-res.c PCI: Use resource names in PCI log messages 2023-12-15 17:28:42 -06:00
slot.c PCI/sysfs: Constify struct kobj_type pci_slot_ktype 2023-02-16 12:00:25 -06:00
syscall.c PCI: Use consistent put_user() pointer types 2023-08-25 08:15:13 -05:00
vc.c PCI/VC: Use FIELD_GET() 2023-10-24 16:55:45 -05:00
vgaarb.c pci-v6.7-changes 2023-11-02 14:05:18 -10:00
vpd.c PCI/VPD: Add runtime power management to sysfs interface 2023-08-11 14:19:16 -05:00
xen-pcifront.c x86: always initialize xen-swiotlb when xen-pcifront is enabling 2023-07-31 17:54:27 +02:00