Re: [PATCH 3/5] mlx5: Avoid that sparse complains about dubious !x & y expressions

[Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>]

On Thu, Dec 08, 2016 at 11:26:32AM +0200, Or Gerlitz wrote:
>  /* insert a value to a struct */
>  #define MLX5_SET(typ, p, fld, v) do { \
> +       typeof( v ) _v = v; \
>         BUILD_BUG_ON(__mlx5_st_sz_bits(typ) % 32);             \
>         *((__be32 *)(p) + __mlx5_dw_off(typ, fld)) = \
>         cpu_to_be32((be32_to_cpu(*((__be32 *)(p) + __mlx5_dw_off(typ, fld))) & \
> -                    (~__mlx5_dw_mask(typ, fld))) | (((v) &
> __mlx5_mask(typ, fld)) \
> +                    (~__mlx5_dw_mask(typ, fld))) | (((_v) &
> __mlx5_mask(typ, fld)) \
>                      << __mlx5_dw_bit_off(typ, fld))); \
>  } while (0)

Ugh, that is ugly.

This is better, it has proper type safety :|

static inline _mlx5_set(__be32 *p, u32 dw_mask,
                        u32 mask, u32 dw_off,
			unsigned int bit_off, u32 val)
{
	*(p + dw_off) = cpu_to_b32((be32_to_cpu_p(p + dw_off) &
	             ~dw_mask) | ((val & mask) << bit_off));
}

#define MLX5_SET(typ, p, fld, v) \
	_mlx5_set(p, __mlx5_dw_mask(typ, fld),
	           __mlx5_mask(typ, fld),
	           __mlx5_dw_off(typ, fld),
		   __mlx5_dw_bit_off(typ, fld), v)

Jason
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