Re: [RFT PATCH 0/9] PCI: Remove pci_fixup_irqs()

[Bjorn Helgaas]

On Mon, Jul 31, 2017 at 05:37:48PM +0100, Lorenzo Pieralisi wrote:
> The pci_fixup_irqs() function allocates IRQs for all PCI devices present
> in a system; those PCI devices possibly belong to different PCI bus trees
> (and possibly rooted at different host bridges) and may well be enabled
> (ie probed and bound to a driver) by the time pci_fixup_irqs() is called
> when probing a given host bridge driver.
> 
> Furthermore, current kernel code relying on pci_fixup_irqs() to
> assign legacy PCI IRQs to devices does not work at all for
> hotplugged devices in that the code carrying out the IRQ fixup
> is called at host bridge driver probe time, which just cannot take
> into account devices hotplugged after system has booted.
> 
> The introduction of map/swizzle functions hook in struct pci_host_bridge
> allows to define per-bridge map/swizzle functions, that can be used at
> device probe time in PCI core code to allocate IRQs for a given device
> (through pci_assign_irq()).
> 
> This series converts all arches still relying on pci_fixup_irqs() to
> the new pci_scan_root_bus_bridge() API and consequently remove
> pci_fixup_irqs() from the kernel in that it is not used anymore.
> 
> Compile tested only, I do not have the necessary hardware.

Yay!  I applied this to pci/irq-fixups for v4.14.

Huge thanks to both Matthew and Lorenzo for all the hard work it took
to make this happen!

> [1] git://git.kernel.org/pub/scm/linux/kernel/git/lpieralisi/linux.git pci/pci-fixup-irqs-removal
> 
> Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
> Cc: Arnd Bergmann <arnd@xxxxxxxx>
> Cc: Paul Burton <paul.burton@xxxxxxxxxx>
> Cc: Rich Felker <dalias@xxxxxxxx>
> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Cc: Richard Henderson <rth@xxxxxxxxxxx>
> Cc: Tanmay Inamdar <tinamdar@xxxxxxx>
> Cc: Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx>
> Cc: Chris Metcalf <cmetcalf@xxxxxxxxxxxx>
> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> Cc: Matthew Minter <matt@xxxxxxxxxxxx>
> Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
> Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> Cc: Guan Xuetao <gxt@xxxxxxxxxxxxxxx>
> 
> Lorenzo Pieralisi (7):
>   sh/PCI: Replace pci_fixup_irqs() call with PCI host bridge IRQ mapping
>     hooks
>   alpha/PCI: Replace pci_fixup_irqs() call with PCI host bridge IRQ
>     mapping hooks
>   m68k/PCI: Replace pci_fixup_irqs() call with PCI host bridge IRQ
>     mapping hooks
>   MIPS/PCI: Replace pci_fixup_irqs() call with PCI host bridge IRQ
>     mapping hooks
>   tile/PCI: Replace pci_fixup_irqs() call with PCI host bridge IRQ
>     mapping hooks
>   unicore32/PCI: Replace pci_fixup_irqs() call with PCI host bridge IRQ
>     mapping hooks
>   sparc/PCI: Replace pci_fixup_irqs() call with PCI host bridge IRQ
>     mapping hooks
> 
> Matthew Minter (2):
>   sh/PCI: Remove __init optimisations from IRQ mapping functions/data
>   PCI: Remove pci_fixup_irqs() function
> 
>  arch/alpha/kernel/pci.c                 | 27 ++++++++++++++++------
>  arch/alpha/kernel/sys_nautilus.c        | 31 +++++++++++++++++++++----
>  arch/m68k/coldfire/pci.c                | 36 +++++++++++++++++++++++++----
>  arch/mips/pci/pci-legacy.c              | 24 +++++++++++++------
>  arch/sh/drivers/pci/fixups-cayman.c     |  2 +-
>  arch/sh/drivers/pci/fixups-dreamcast.c  |  2 +-
>  arch/sh/drivers/pci/fixups-r7780rp.c    |  2 +-
>  arch/sh/drivers/pci/fixups-rts7751r2d.c |  6 ++---
>  arch/sh/drivers/pci/fixups-sdk7780.c    |  4 ++--
>  arch/sh/drivers/pci/fixups-se7751.c     |  2 +-
>  arch/sh/drivers/pci/fixups-sh03.c       |  2 +-
>  arch/sh/drivers/pci/fixups-snapgear.c   |  2 +-
>  arch/sh/drivers/pci/fixups-titan.c      |  4 ++--
>  arch/sh/drivers/pci/pci.c               | 41 ++++++++++++++++++++-------------
>  arch/sh/drivers/pci/pcie-sh7786.c       |  2 +-
>  arch/sparc/kernel/leon_pci.c            | 24 ++++++++++++++-----
>  arch/tile/kernel/pci.c                  | 21 +++++++++++++----
>  arch/tile/kernel/pci_gx.c               | 21 +++++++++++++----
>  arch/unicore32/kernel/pci.c             | 35 ++++++++++++++++++++++++----
>  drivers/pci/setup-irq.c                 | 24 -------------------
>  include/linux/pci.h                     |  2 --
>  21 files changed, 216 insertions(+), 98 deletions(-)
> 
> -- 
> 2.10.0
>