On Tue, Jun 21, 2016 at 07:58:08PM +0800, wangyijing wrote: > Hi Bjorn, use devm_request_resource() for host bridge resource is cool, > what about do the similar change for x86, now we request host bridge resource > in pci_acpi_root_add_resources() in x86, and we would release the host bridge > resource when host bridge device refcount reach 0. This logic may introduce issue, > E.g. > If we try to remove a pci host bridge, but there is a child pci device which refcount > cannot decrease to 0 after remove the device, in this case, its parent pci_bus and > parent device, all their refcount cannot reach to 0, the result is pci host bridge > refcount can not reach 0, so its .release_fn() won't be called, and host bridge > resouces can not release. If we want to add the pci host bridge again, all pci devices > can not work because the resource is conflict with the old. > > devm resource would be released when the driver detach, this is better than what we do now, I think. I'm not going to convert pci_root.c to use devm right now. That might be a good thing, but this current series is mostly trivial. I think changing pci_root.c would not be trivial, so that looks like a project all by itself. I don't quite follow the example of removing a host bridge while a child PCI device refcount is non-zero. That sounds like an invalid scenario regardless of whether the resources are released by a .release_fn() or by devm. Bjorn
