在 2016/6/21 23:03, Bjorn Helgaas 写道: > 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. OK. > > 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. I would send a draft patch to describe and fix the issue, because it's not related to this series, so let's discuess it in another thread. :) Thanks! Yijing. > > Bjorn > > . >
