Hi all,
This is v5 of the series that implements a series of changes
that allows the PCI core to manage slot names, rather than
individual hotplug drivers.
Thanks again to Kenji-san for continuing to point out that my
previous attempts were racy and had horrible, complicated code. :)
And thanks to Willy for reviewing my poor attempt at introducing
locking.
I've decided to do them both a favor and take a new approach that
does not change any locking semantics in any of the existing interfaces
today (pci_hp_register, pci_hp_deregister, pci_create_slot).
Keep in mind that the problems we're trying to solve are:
- possible duplicate slot names from firmware
- allow hotplug drivers to override detection driver slot names
The race that Kenji-san points out occurs during slot creation, where
both a detection driver and hotplug driver try to create a slot at
the same time, with different names.
The solution is to combine slot creation _and_ slot rename into one
atomic operation via an updated pci_create_slot() API. pci_create_slot
is already serialized, so that's a good start.
We add a 'rename' parameter to pci_create_slot. The hotplug drivers set
it to 1. The detection drivers set it to 0. Now, when trying to create
a new slot:
- check to see if it's already been created
- if yes, and we want a rename, then go ahead and rename it
- if yes, and we don't care about the name, then just return
- if no, then create the slot normally
This logic is fully described in the changelog in patch 04/16. I believe
it is a much simpler approach than the earlier crap I was producing.
I tested this series with the pci_slot driver and fakephp dup_slots=1
with multiple loads and unloads in different order, and it all seemed
to work.
I _hope_ this is the last round. ;)
Thanks!
/ac
v4 -> v5:
- add 'rename' param to pci_create_slot
- make use of 'rename' param in pci_create_slot
- remove v4 serialization
- remove crap false name collsion code from v2 and v3
- rpaphp uses kstrdup (Thanks to Pekka Enberg for suggestion)
v3 -> v4:
- Do not access hotplug_slot_name() before name initialization
- Serialize pci_hp_register/deregister
v2 -> v3:
- incorporate Willy's code review comments
- fix possible memory leak, pointed out by Rolf Eike Beer
- make false name collision detection work for empty slots
- add 'dup_slots' module_param to fakephp to help debug all this ;)
v1 -> v2:
- fix possible false name collisions
---
Alex Chiang (16):
PCI Hotplug: fakephp: add duplicate slot name debugging
PCI: Hotplug core: remove 'name'
PCI: shcphp: remove 'name' parameter
PCI: SGI Hotplug: stop managing bss_hotplug_slot->name
PCI: rpaphp: kmalloc/kfree slot->name directly
PCI: pciehp: remove 'name' parameter
PCI: ibmphp: stop managing hotplug_slot->name
PCI: fakephp: remove 'name' parameter
PCI: cpqphp: stop managing hotplug_slot->name
PCI: cpci_hotplug: stop managing hotplug_slot->name
PCI: acpiphp: remove 'name' parameter
PCI, PCI Hotplug: introduce slot_name helpers
PCI: prevent duplicate slot names
PCI: update pci_create_slot() to take a 'rename' param
PCI: rename pci_update_slot_number to pci_renumber_slot
PCI Hotplug core: add 'name' param pci_hp_register interface
drivers/acpi/pci_slot.c | 2
drivers/pci/hotplug/acpiphp.h | 9 +-
drivers/pci/hotplug/acpiphp_core.c | 32 ++++---
drivers/pci/hotplug/cpci_hotplug.h | 6 +
drivers/pci/hotplug/cpci_hotplug_core.c | 75 ++++++----------
drivers/pci/hotplug/cpci_hotplug_pci.c | 4 -
drivers/pci/hotplug/cpqphp.h | 13 +--
drivers/pci/hotplug/cpqphp_core.c | 43 ++++-----
drivers/pci/hotplug/fakephp.c | 26 ++++-
drivers/pci/hotplug/ibmphp.h | 5 -
drivers/pci/hotplug/ibmphp_ebda.c | 19 +---
drivers/pci/hotplug/pci_hotplug_core.c | 30 ++----
drivers/pci/hotplug/pciehp.h | 9 +-
drivers/pci/hotplug/pciehp_core.c | 49 ++++------
drivers/pci/hotplug/pciehp_ctrl.c | 53 ++++++-----
drivers/pci/hotplug/pciehp_hpc.c | 1
drivers/pci/hotplug/rpaphp_slot.c | 10 +-
drivers/pci/hotplug/sgi_hotplug.c | 18 +---
drivers/pci/hotplug/shpchp.h | 9 +-
drivers/pci/hotplug/shpchp_core.c | 52 ++++-------
drivers/pci/hotplug/shpchp_ctrl.c | 48 +++++-----
drivers/pci/slot.c | 150 ++++++++++++++++++++++++-------
include/linux/pci.h | 9 +-
include/linux/pci_hotplug.h | 11 +-
24 files changed, 359 insertions(+), 324 deletions(-)
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