PCI: Lock upstream bridge for pci_reset_function()
Fix a long-standing locking gap for missing pci_cfg_access_lock() while
manipulating bridge reset registers and configuration during
pci_reset_bus_function().
If there is an upstream bridge, lock it before locking the device itself.
pci_dev_lock() calls pci_cfg_access_lock(), which blocks the writing of PCI
config space by user space.
Add lockdep assertion via pci_dev->cfg_access_lock to verify
pci_dev->block_cfg_access is set.
Co-developed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/20240502165851.1948523-3-dave.jiang@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>