Re: [PATCH v3 1/7] mm/x86: Use SWP_TYPE_BITS in 3-level swap macros

[Huang, Ying]

Peter Xu <peterx@xxxxxxxxxx> writes:

> Replace all the magic "5" with the macro.
>
> Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
> Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>

Reviewed-by: "Huang, Ying" <ying.huang@xxxxxxxxx>

Best Regards,
Huang, Ying

> ---
>  arch/x86/include/asm/pgtable-3level.h | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/include/asm/pgtable-3level.h b/arch/x86/include/asm/pgtable-3level.h
> index e896ebef8c24..28421a887209 100644
> --- a/arch/x86/include/asm/pgtable-3level.h
> +++ b/arch/x86/include/asm/pgtable-3level.h
> @@ -256,10 +256,10 @@ static inline pud_t native_pudp_get_and_clear(pud_t *pudp)
>  /* We always extract/encode the offset by shifting it all the way up, and then down again */
>  #define SWP_OFFSET_SHIFT	(SWP_OFFSET_FIRST_BIT + SWP_TYPE_BITS)
>  
> -#define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > 5)
> -#define __swp_type(x)			(((x).val) & 0x1f)
> -#define __swp_offset(x)			((x).val >> 5)
> -#define __swp_entry(type, offset)	((swp_entry_t){(type) | (offset) << 5})
> +#define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > SWP_TYPE_BITS)
> +#define __swp_type(x)			(((x).val) & ((1UL << SWP_TYPE_BITS) - 1))
> +#define __swp_offset(x)			((x).val >> SWP_TYPE_BITS)
> +#define __swp_entry(type, offset)	((swp_entry_t){(type) | (offset) << SWP_TYPE_BITS})
>  
>  /*
>   * Normally, __swp_entry() converts from arch-independent swp_entry_t to