linux-kernel - Re: [PATCH 00/14] PCI: trivial demodularization of builtin code

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Date:	Fri, 22 Jul 2016 16:52:46 -0500
From:	Bjorn Helgaas <helgaas@...nel.org>
To:	Paul Gortmaker <paul.gortmaker@...driver.com>
Cc:	linux-kernel@...r.kernel.org, Alexandre Courbot <gnurou@...il.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	David Daney <david.daney@...ium.com>,
	Gabriele Paoloni <gabriele.paoloni@...wei.com>,
	Jason Cooper <jason@...edaemon.net>,
	Jesper Nilsson <jesper.nilsson@...s.com>,
	Jingoo Han <jingoohan1@...il.com>,
	Joao Pinto <jpinto@...opsys.com>,
	Minghuan Lian <minghuan.Lian@...escale.com>,
	Mingkai Hu <mingkai.hu@...escale.com>,
	Murali Karicheri <m-karicheri2@...com>,
	Niklas Cassel <niklas.cassel@...s.com>,
	Phil Edworthy <phil.edworthy@...esas.com>,
	Pratyush Anand <pratyush.anand@...il.com>,
	Roy Zang <tie-fei.zang@...escale.com>,
	Simon Horman <horms@...ge.net.au>,
	Stephen Warren <swarren@...dotorg.org>,
	Tanmay Inamdar <tinamdar@....com>,
	Thierry Reding <thierry.reding@...il.com>,
	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
	Valentine Barshak <valentine.barshak@...entembedded.com>,
	Will Deacon <will.deacon@....com>,
	Zhou Wang <wangzhou1@...ilicon.com>, linux-pci@...r.kernel.org,
	linux-tegra@...r.kernel.org
Subject: Re: [PATCH 00/14] PCI: trivial demodularization of builtin code

On Sat, Jul 02, 2016 at 07:13:20PM -0400, Paul Gortmaker wrote:
> Firstly, this group of commits was chosen for the fact that they don't
> change anything even at a binary object file level ; they just replace
> module_platform_driver with builtin_platform_driver, and remove some
> MODULE_<blah> tags that are no-ops in code.  So the regression risk
> is zero here.
> 
> More specifically, we are doing the following to pci/host files that
> currently can only be built-in:
> 
>  -- remove the include of module.h ; replace it with init.h as req'd
> 
>  -- drop instances of MODULE_DEVICE_TABLE which is a no-op built-in.
> 
>  -- replace module_platform_driver with builtin_platform_driver, which
>     is functionally identical once CPP has processed the source.
> 
>  -- drop instances of MODULE_LICENSE, MODULE_AUTHOR, MODULE_DESCRIPTION
>     while ensuring the contained info is present in the file comments.
> 
> After considering the inital version of demodularization PCI host
> commits[1], we did consider striving for tristate[2] on another
> subset of PCI host files in order to keep bzImage sizes lower on
> multi-platform builds, but that proved to have technical challenges
> well outside the scope of what we are trying to achieve here, given
> PCI is infrastructure code and not a case of simple endpoint
> drivers.
> 
> In the meantime more new code copies the existing examples of bool
> Kconfig using modular references; further expanding the problem
> space.  So we are just going to proceed with the demodularization
> as originally planned.  Nothing removed here is rocket science, and
> can easily be restored if someone has the hardware to test on and
> the desire to expand functionality into the tristate realm.
> 
> A more complete description of why we are doing this can be found
> in the original posting[1] for those that haven't seen it yet.
> 
> This represents just over 1/2 the PCI drivers that have their Kconfig
> as bool but needlessly use modular references.  The remainder do not
> deliver exact binary equivalence, since they delete unused __exit
> functions and/or unused ".remove" functions.  So they are more
> appropriate for submission earlier in the next development window.
> 
> Build tested for allmodconfig on several arch, including ARM and
> ARM-64 on the most recent linux-next baseline.
> 
> Paul.
> 
> [1] https://lkml.kernel.org/r/1449970917-12633-1-git-send-email-paul.gortmaker@windriver.com
> [2] https://lkml.kernel.org/r/1454889644-27830-1-git-send-email-paul.gortmaker@windriver.com
> 
> ---
> 
> [vs v1 in [1] above, I tweaked the subjects slightly to match the
>  format used by most PCI commits, i.e drop the "driver/" prefix. ]
> 
> Cc: Alexandre Courbot <gnurou@...il.com>
> Cc: Bjorn Helgaas <bhelgaas@...gle.com>
> Cc: David Daney <david.daney@...ium.com>
> Cc: Gabriele Paoloni <gabriele.paoloni@...wei.com>
> Cc: Jason Cooper <jason@...edaemon.net>
> Cc: Jesper Nilsson <jesper.nilsson@...s.com>
> Cc: Jingoo Han <jingoohan1@...il.com>
> Cc: Joao Pinto <jpinto@...opsys.com>
> Cc: Minghuan Lian <minghuan.Lian@...escale.com>
> Cc: Mingkai Hu <mingkai.hu@...escale.com>
> Cc: Murali Karicheri <m-karicheri2@...com>
> Cc: Niklas Cassel <niklas.cassel@...s.com>
> Cc: Phil Edworthy <phil.edworthy@...esas.com>
> Cc: Pratyush Anand <pratyush.anand@...il.com>
> Cc: Roy Zang <tie-fei.zang@...escale.com>
> Cc: Simon Horman <horms@...ge.net.au>
> Cc: Stephen Warren <swarren@...dotorg.org>
> Cc: Tanmay Inamdar <tinamdar@....com>
> Cc: Thierry Reding <thierry.reding@...il.com>
> Cc: Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>
> Cc: Valentine Barshak <valentine.barshak@...entembedded.com>
> Cc: Will Deacon <will.deacon@....com>
> Cc: Zhou Wang <wangzhou1@...ilicon.com>
> Cc: linux-pci@...r.kernel.org
> Cc: linux-tegra@...r.kernel.org
> 
> Paul Gortmaker (14):
>   PCI: armada8k: make it explicitly non-modular
>   PCI: artpec6: make it explicitly non-modular
>   PCI: designware-plat: make it explicitly non-modular
>   PCI: generic: make it explicitly non-modular
>   PCI: hisi: make it explicitly non-modular
>   PCI: keystone: make it explicitly non-modular
>   PCI: layerscape: make it explicitly non-modular
>   PCI: mvebu: make it explicitly non-modular
>   PCI: rcar: make it explicitly non-modular
>   PCI: rcar-gen2: make it explicitly non-modular
>   PCI: tegra: make it explicitly non-modular
>   PCI: thunder-ecam: make it explicitly non-modular
>   PCI: thunder-pem: make it explicitly non-modular
>   PCI: xgene: make it explicitly non-modular
> 
>  drivers/pci/host/pci-host-generic.c     | 10 ++--------
>  drivers/pci/host/pci-keystone.c         | 10 ++--------
>  drivers/pci/host/pci-layerscape.c       | 10 ++--------
>  drivers/pci/host/pci-mvebu.c            | 11 ++++-------
>  drivers/pci/host/pci-rcar-gen2.c        | 12 +++---------
>  drivers/pci/host/pci-tegra.c            | 11 ++++-------
>  drivers/pci/host/pci-thunder-ecam.c     |  8 ++------
>  drivers/pci/host/pci-thunder-pem.c      |  8 ++------
>  drivers/pci/host/pci-xgene.c            |  8 ++------
>  drivers/pci/host/pcie-armada8k.c        | 14 +++++---------
>  drivers/pci/host/pcie-artpec6.c         | 10 ++--------
>  drivers/pci/host/pcie-designware-plat.c | 10 ++--------
>  drivers/pci/host/pcie-hisi.c            | 13 ++-----------
>  drivers/pci/host/pcie-rcar.c            | 11 ++++-------
>  14 files changed, 38 insertions(+), 108 deletions(-)

Applied to pci/demodularize-hosts for v4.8, thanks, Paul!