PCI service interrupt handlers & access to PCI config space

["Pali Rohár" <pali@kernel.org>]

Hello!

I see that more PCI service drivers in their interrupt handlers are
accessing PCI config space.

E.g. in PCIe Hot Plug interrupt handler pciehp_isr handler is called
pcie_capability_read_word() function.

It is correct? Because these capability functions are protected by
pci_lock_config() / pci_unlock_config() calls.

And what would happen when during execution of reading or writing to
PCIe config space (e.g. via pcie_capability_read_word()) is triggered
PCIe HP interrupt? Would not enter interrupt handler function in
deadlock (waiting for unlocking config space)?