Re: linux-next: Tree for Aug 8 (not CONFIG_PCI_MSI conflict)

[Bjorn Helgaas]

On Fri, Aug 9, 2013 at 12:50 PM, Jason Cooper <jason@xxxxxxxxxxxxxx> wrote:
> Randy,
>
> On Fri, Aug 09, 2013 at 09:41:38AM -0700, Randy Dunlap wrote:
>> On 08/09/13 07:59, Jason Cooper wrote:
>> > Randy,
>> >
>> > On Thu, Aug 08, 2013 at 01:03:04PM -0700, Randy Dunlap wrote:
>> >> On 08/08/13 00:08, Stephen Rothwell wrote:
>> >>> Hi all,
>> >>>
>> >>> Changes since 20130807:
>> >>>
>> >>
>> >> on i386 and x86_64:
>> >> when CONFIG_PCI_MSI is not enabled:
>> >>
>> >> There are many of these errors:
>> >> include/linux/msi.h:65:6: error: expected identifier or '(' before 'void'
>> >> include/linux/msi.h:65:6: error: expected ')' before numeric constant
>> >>
>> >> because arch/x86/include/asm/pci.h defines:
>> >> #define default_teardown_msi_irqs  NULL
>> >
>> > Do you have an example config you used?
>>
>> Sure, attached. (or I have 14 of them)
>
> Thanks, I was able to reproduce the error.  I'm not real familiar with
> this area of the code, but the relief is it doesn't appear to be caused
> by the mvebu changes (well, relief for us ;-) ).
>
> At any rate, give this a spin and see if it works for you
>
> If it's acceptable, I'll do an official patch for Bjorn.
>
> thx,
>
> Jason.
>
> ---------->8----------
> diff --git a/arch/x86/include/asm/pci.h b/arch/x86/include/asm/pci.h
> index d9e9e6c..6169414 100644
> --- a/arch/x86/include/asm/pci.h
> +++ b/arch/x86/include/asm/pci.h
> @@ -138,8 +138,8 @@ void default_restore_msi_irqs(struct pci_dev *dev, int irq);
>  #else
>  #define native_setup_msi_irqs          NULL
>  #define native_teardown_msi_irq                NULL
> -#define default_teardown_msi_irqs      NULL
> -#define default_restore_msi_irqs       NULL
> +void __weak default_teardown_msi_irqs(struct pci_dev *dev) { }
> +void __weak default_restore_msi_irqs(struct pci_dev *dev, int irq) { }

I don't really like this solution of putting the empty implementation
in the header file, because then a weak body is generated in the
object of every source file that includes the header.

default_teardown_msi_irqs() and default_restore_msi_irqs() seem like
fairly internal MSI functions, so I wonder why we need them defined at
all when CONFIG_PCI_MSI=n.  It seems like any uses of them should be
in code that's only compiled when CONFIG_PCI_MSI=y.  But I haven't
reproduced the problem and investigated yet.

>  #endif
>
>  #define PCI_DMA_BUS_IS_PHYS (dma_ops->is_phys)
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