LinuxKPI: pci: implement pci_upstream_bridge()
ClosedPublic
Actions

Authored by bz on Feb 16 2022, 6:34 PM.

Details

Reviewers

jhb
grehan
• hselasky

Group Reviewers

linuxkpi
x11

Commits

rGa85cf68895d4: LinuxKPI: pci: implement pci_upstream_bridge()
rG50136233846e: LinuxKPI: pci: implement pci_upstream_bridge()
rGb3b836251f9f: LinuxKPI: pci: implement pci_upstream_bridge()

Summary

Currently we point back to ourselves on pdev->bus->self rather than
the parent PCI bridge.

We keep this as status-quo with an extra comment and only on-demand
allocate a pci_dev for the parent bridge if we are asked for in
pci_upstream_bridge().
When releasing the pci_dev we check if pdev->bus->self has changed
and call pci_dev_put() to release the reference count on the parent
bridge as well.

This code moves pci_is_root_bus() higher up in pci.h but no functional
change there.

Sponsored by: The FreeBSD Foundation
MFC after: 3 days

Test Plan

Adding x11 to reviewers as this conflicts with the
implementation there.

I'll also need to MFC this.

Diff Detail

Repository

rS FreeBSD src repository - subversion

Lint

Lint Passed

Unit

No Test Coverage

Build Status

Buildable 44770
Build 41658: arc lint + arc unit

Event Timeline

bz created this revision.Feb 16 2022, 6:34 PM

Herald added subscribers: emaste, imp. · View Herald TranscriptFeb 16 2022, 6:35 PM

bz requested review of this revision.Feb 16 2022, 6:35 PM

Harbormaster completed remote builds in B44484: Diff 102849.Feb 16 2022, 6:35 PM

Sorry to add you here but I know you to know PCI very well; I found pci_find_pcie_root_port() but nothing which just walks up the PCI bridge tree step by step as a function to the next step so I am going with what other people also have done in sys/dev/ and got two up and check the class on that parent. Is that sane? I wonder if we should indeed (in the future) add a function and then replace then 2-3 places throughout the tree with that...?

x11 I opened a pull request which will remove the conflict : https://github.com/freebsd/drm-kmod/pull/152/commits/a35463b86a3babd4b580dab5f447d215478036ee If possible please apply to the devel/current/13 versions so this could proceed once reviewed.

jhb added inline comments.Feb 23 2022, 11:43 PM