linux-kernel - Re: [PATCH, resend] x86/PCI: don't export a _

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Message-ID: <AANLkTik8B_evoOh_B9=2w=5nDAheZZiZLWyLGHavPy1c@mail.gmail.com>
Date:	Thu, 17 Feb 2011 09:21:54 -0800
From:	Yinghai Lu <yinghai@...nel.org>
To:	Jan Beulich <JBeulich@...ell.com>,
	"Barnes, Jesse" <jesse.barnes@...el.com>
Cc:	mingo@...e.hu, tglx@...utronix.de, hpa@...or.com,
	arozansk@...hat.com, mchehab@...hat.com,
	Michal Marek <mmarek@...e.cz>, linux-kernel@...r.kernel.org,
	linux-pci@...r.kernel.org
Subject: Re: [PATCH, resend] x86/PCI: don't export a __devinit function

On Thu, Feb 17, 2011 at 8:08 AM, Jan Beulich <JBeulich@...ell.com> wrote:
> Exporting a __devinit function (pcibios_scan_specific_bus()) isn't
> correct. (Michal, any reason why modpost only warns about exported
> __init functions?) Short of being able to think of a better solution,
> and short of making the whole call tree (reaching into the arch-
> independent part of the PCI subsystem) non-__devinit, export the
> symbol only when HOTPLUG is enabled (which is always the case for non-
> expert configurations), use section mismatch avoidance annotations for
> that case (knowing that __devinit functions will not be discarded),
> and mark the symbol __devinit only in the !HOTPLUG case.
>
> Consequently, EDAC_I7CORE (consuming the export) then has to depend on
> HOTPLUG. A fundamental question of course if whether this driver has
> to use that function in the first place (i.e. whether it wouldn't be
> better to just remove the export) - the problem it tries to address
> happens on other systems too, but the PCI bus the devices in question
> live on isn't necessarily bus 255. For the affected system I have, the
> alternative approach is to set pcibios_last_bus from __pci_mmcfg_init()
> based on the highest bus number on segment 0 being covered by MCFG.
>
> Signed-off-by: Jan Beulich <jbeulich@...ell.com>
> Cc: Mauro Carvalho Chehab <mchehab@...hat.com>
> Cc: Aristeu Sergio <arozansk@...hat.com>
> Cc: Michal Marek <mmarek@...e.cz>
>
> ---
>  arch/x86/pci/legacy.c |   21 ++++++++++++++++++---
>  drivers/edac/Kconfig  |    2 +-
>  2 files changed, 19 insertions(+), 4 deletions(-)
>
> --- 2.6.38-rc5/arch/x86/pci/legacy.c
> +++ 2.6.38-rc5-x86-pci-section-conflict/arch/x86/pci/legacy.c
> @@ -36,7 +36,23 @@ int __init pci_legacy_init(void)
>        return 0;
>  }
>
> -void __devinit pcibios_scan_specific_bus(int busn)
> +#ifdef CONFIG_HOTPLUG
> +static void __ref
> +#else
> +static inline void
> +#endif
> +_pci_scan_bus_on_node(int busno, int node)
> +{
> +       pci_scan_bus_on_node(busno, &pci_root_ops, node);
> +}
> +
> +#ifdef CONFIG_HOTPLUG
> +EXPORT_SYMBOL_GPL(pcibios_scan_specific_bus);
> +void
> +#else
> +void __devinit
> +#endif

anyway to avoid or reduce those #ifdef?

Yinghai

> +pcibios_scan_specific_bus(int busn)
>  {
>        int devfn;
>        long node;
> @@ -51,12 +67,11 @@ void __devinit pcibios_scan_specific_bus
>                    l != 0x0000 && l != 0xffff) {
>                        DBG("Found device at %02x:%02x [%04x]\n", busn, devfn, l);
>                        printk(KERN_INFO "PCI: Discovered peer bus %02x\n", busn);
> -                       pci_scan_bus_on_node(busn, &pci_root_ops, node);
> +                       _pci_scan_bus_on_node(busn, node);
>                        return;
>                }
>        }
>  }
> -EXPORT_SYMBOL_GPL(pcibios_scan_specific_bus);
>
>  int __init pci_subsys_init(void)
>  {
> --- 2.6.38-rc5/drivers/edac/Kconfig
> +++ 2.6.38-rc5-x86-pci-section-conflict/drivers/edac/Kconfig
> @@ -173,7 +173,7 @@ config EDAC_I5400
>
>  config EDAC_I7CORE
>        tristate "Intel i7 Core (Nehalem) processors"
> -       depends on EDAC_MM_EDAC && PCI && X86
> +       depends on EDAC_MM_EDAC && PCI && X86 && HOTPLUG
>        select EDAC_MCE
>        help
>          Support for error detection and correction the Intel
>
>
>
> --
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