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[0/2] pcie hotplug and error fixes

Message ID 20240610220304.3162895-1-kbusch@meta.com
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Series pcie hotplug and error fixes | expand

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Keith Busch June 10, 2024, 10:03 p.m. UTC 
From: Keith Busch <kbusch@kernel.org>

I am working with larger pcie topologies again, and we're seeing some
failures when dealing with certain overlapping pcie events.

The topology is essentially this:

  [Root Port] <-> [UpStream Port] <-> [DownStream Port] <-> [End Device]

An error between the DSP and ED triggers DPC. There's only inband
presence detection so it also triggers hotplug. Before the error
handling is completed, though, another error seen by the RP triggers its
own DPC handling.

The concurrent event handling reveals some interesting races, and this
small patchset tries to address these in the low invasive way.

Keith Busch (2):
  PCI: pciehp: fix concurrent sub-tree removal deadlock
  PCI: err: ensure stable topology during handling

 drivers/pci/hotplug/pciehp_pci.c | 12 +++++++++---
 drivers/pci/pci.h                |  1 +
 drivers/pci/pcie/err.c           |  8 +++++++-
 drivers/pci/probe.c              | 24 ++++++++++++++++++++++++
 include/linux/pci.h              |  2 ++
 5 files changed, 43 insertions(+), 4 deletions(-)