[RFC 4/8] powerpc/slb: Add some helper functions to improve modularization

[Michael Ellerman]

On Tue, 2015-07-21 at 12:28 +0530, Anshuman Khandual wrote:
> From: "khandual at linux.vnet.ibm.com" <khandual at linux.vnet.ibm.com>
> 
> This patch adds the following helper functions to improve modularization
> and readability of the code.
> 
> (1) slb_invalid_all: 		Invalidates entire SLB

This reads badly. Although invalid can be a verb, the meaning of invalid as a
verb is not correct here. You want "invalidate".

> (2) slb_invalid_paca_slots: 	Invalidate SLB entries present in PACA

Ditto.

But, I think that's the wrong abstraction.

We should just have one routine, slb_invalidate(), which deals with all the
mess. ie. checking the MMU_FTR and the offset etc. So basically the whole
if/else.

> (3) kernel_linear_vsid_flags:	VSID flags for kernel linear mapping
> (4) kernel_virtual_vsid_flags:	VSID flags for kernel virtual mapping

I don't like these names either.

> diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c
> index cbeaaa2..dcba4c2 100644
> --- a/arch/powerpc/mm/slb.c
> +++ b/arch/powerpc/mm/slb.c
> @@ -94,18 +94,37 @@ static inline void new_shadowed_slbe(unsigned long ea, int ssize,
>  		     : "memory" );
>  }
>  
> +static inline unsigned long kernel_linear_vsid_flags(void)
> +{
> +	return SLB_VSID_KERNEL | mmu_psize_defs[mmu_linear_psize].sllp;
> +}

mmu_linear_vsid_flags() ?

> +
> +static inline unsigned long kernel_virtual_vsid_flags(void)
> +{
> +	return SLB_VSID_KERNEL | mmu_psize_defs[mmu_vmalloc_psize].sllp;
> +}

mmu_vmalloc_vsid_flags() ?

etc.

ie. have the function names match the mmu psize names. I don't think we need
"kernel" in the name, I think that's implied.

cheers