amba-pl08x and 'get_signal' namespace collision/build error

[Steve Capper]

On Tue, Jun 25, 2013 at 07:45:39PM +0100, Russell King - ARM Linux wrote:
> On Tue, Jun 25, 2013 at 12:30:08PM +0100, Jonathan Austin wrote:
> > There's a patch making its way to mainline via Russell's tree
> > (8d96250700: ARM: mm: Transparent huge page support for LPAE systems)
> > that breaks the build of the amba-pl08x driver (drivers/dma/amba-pl08x.c) 
> > because the 'get_signal' macro from include/linux/signal.h is now in the
> > driver's scope and it clobbers a (previously) valid function call.
> 
> Well, here's the change to asm/pgtable.h in that patch:
> 
> diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
> index 9bcd262..eaedce7 100644
> --- a/arch/arm/include/asm/pgtable.h
> +++ b/arch/arm/include/asm/pgtable.h
> @@ -24,6 +24,9 @@
>  #include <asm/memory.h>
>  #include <asm/pgtable-hwdef.h>
> 
> +
> +#include <asm/tlbflush.h>
> +
>  #ifdef CONFIG_ARM_LPAE
>  #include <asm/pgtable-3level.h>
>  #else
> 
> And the question is - if that's all that is going on in that file, why
> is asm/tlbflush.h being added to it?  What in _that_ file uses anything
> from asm/tlbflush.h (nothing apparantly from what I can see)?
> 
> So, I'm tempted to kill this change off unless someone can justify why
> that addition happened - it looks completely inappropriate to me.
> 

Hi Russell,
I needed tlbflush.h for the definition of flush_pmd_entry, called by set_pmd_at
in pgtable-3level.h.

It was pulled into pgtable.h as it would also be needed for the equivalent
set_pmd_at function for 2-levels of paging.

Best,
-- 
Steve