Re: [PATCH 00/11] Enhancements and bugfixes to PCI hotplug subsystem

[Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>]

> The second prososal is to introduce a recursive mutex lock to
> serialize all hotplug operations triggered by sysfs interfaces,
> PCI HPC hardware events, ACPI hotplug events and other sources.

The pciehp (and other hotplug controllers) needs this too.

There is only one mutex in the current implementation. I think it
would be better if we can have the mutex per host bridge or per bus
or something so that we can run multiple hot-plug operation in
parallel on the independent PCI sub trees.

Regards,
Kenji Kaneshige



(2012/03/23 23:58), Jiang Liu wrote:
> This is a series of RFC patches, to make sure we are doing the
> right thing in the right way.  The patchset hasn't been tested yet.
> There are several minor bugfixes and two proposals.
> 
> The first proposal is to add notification chain for PCI hotplug events,
> so other components interested in PCI root/bus/device hotplug events
> could subscribe to the chain.
> 
> The second prososal is to introduce a recursive mutex lock to
> serialize all hotplug operations triggered by sysfs interfaces,
> PCI HPC hardware events, ACPI hotplug events and other sources.
> 
> There are still works left in driver/pci/hotplug directory to apply
> the above two proposals.
> 
> The patchset applies to Yinghai's work on PCI root bus hotplug at
> git://git.kernel.org/pub/scm/linux/kernel/git/yinghai/linux-yinghai.git for-x86-irq
> And it depends on my previous patchset, please refer to
> http://www.spinics.net/lists/linux-pci/msg14472.html
> 
> Thanks!
> 
> Jiang Liu (11):
>    PCI: Fix device reference count leakage in pci_dev_present()
>    PCI: introduce pci_bus_get()/pci_bus_put() to hide implementation
>      details
>    PCI: clean up root bridge related logic in acpiphp driver
>    ACPI,PCI: fix race windows caused by alloc_acpi_hotplug_work()
>    PCI: Add notification interfaces for PCI root/bus/device hotplug
>      events
>    ACPI,PCI: update ACPI<->PCI binding information when pci hotplug
>      event happens
>    ACPI,PCI: update ACPI slots when PCI hotplug event happens
>    PCI: Introduce recursive mutex to serialize PCI hotplug operations
>    PCI: serialize hotplug operations triggered by PCI hotplug sysfs
>      interfaces
>    PCI,ACPI: serialize hotplug operations triggered by ACPI subsystem
>    PCI: Serialize hotplug operations triggered by acpiphp driver
> 
>   drivers/acpi/pci_bind.c                |  115 +++++++++++++++++++++++++
>   drivers/acpi/pci_root.c                |    8 ++
>   drivers/acpi/pci_slot.c                |   81 ++++++++++++++++++-
>   drivers/pci/bus.c                      |   20 ++++-
>   drivers/pci/hotplug.c                  |   47 +++++++++++
>   drivers/pci/hotplug/acpiphp.h          |    7 ++-
>   drivers/pci/hotplug/acpiphp_glue.c     |  143 ++++++++++++--------------------
>   drivers/pci/hotplug/pci_hotplug_core.c |    2 +
>   drivers/pci/pci-sysfs.c                |   29 +++----
>   drivers/pci/pci.h                      |    8 ++
>   drivers/pci/probe.c                    |   10 ++-
>   drivers/pci/remove.c                   |   20 ++++-
>   drivers/pci/search.c                   |   10 +-
>   include/linux/pci.h                    |   57 +++++++++++++
>   14 files changed, 437 insertions(+), 120 deletions(-)
>