Re: [PATCH 1/4] drm/i915/params: use generics for parameter printing

[Luca Coelho <luca@xxxxxxxxx>]

On Wed, 2023-01-18 at 17:17 +0200, Jani Nikula wrote:
> Replace the __builtin_strcmp() if ladder with generics.
> 
> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> ---

Neat! I learned something new.  For the whole series:

Reviewed-by: Luca Coelho <luciano.coelho@xxxxxxxxx>


>  drivers/gpu/drm/i915/i915_params.c | 55 +++++++++++++++++++-----------
>  1 file changed, 36 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
> index d634bd3f641a..6482e878f31e 100644
> --- a/drivers/gpu/drm/i915/i915_params.c
> +++ b/drivers/gpu/drm/i915/i915_params.c
> @@ -222,27 +222,44 @@ i915_param_named_unsafe(lmem_size, uint, 0400,
>  i915_param_named_unsafe(lmem_bar_size, uint, 0400,
>  			"Set the lmem bar size(in MiB).");
>  
> -static __always_inline void _print_param(struct drm_printer *p,
> -					 const char *name,
> -					 const char *type,
> -					 const void *x)
> +static void _param_print_bool(struct drm_printer *p, const char *name,
> +			      bool val)
>  {
> -	if (!__builtin_strcmp(type, "bool"))
> -		drm_printf(p, "i915.%s=%s\n", name,
> -			   str_yes_no(*(const bool *)x));
> -	else if (!__builtin_strcmp(type, "int"))
> -		drm_printf(p, "i915.%s=%d\n", name, *(const int *)x);
> -	else if (!__builtin_strcmp(type, "unsigned int"))
> -		drm_printf(p, "i915.%s=%u\n", name, *(const unsigned int *)x);
> -	else if (!__builtin_strcmp(type, "unsigned long"))
> -		drm_printf(p, "i915.%s=%lu\n", name, *(const unsigned long *)x);
> -	else if (!__builtin_strcmp(type, "char *"))
> -		drm_printf(p, "i915.%s=%s\n", name, *(const char **)x);
> -	else
> -		WARN_ONCE(1, "no printer defined for param type %s (i915.%s)\n",
> -			  type, name);
> +	drm_printf(p, "i915.%s=%s\n", name, str_yes_no(val));
>  }
>  
> +static void _param_print_int(struct drm_printer *p, const char *name,
> +			     int val)
> +{
> +	drm_printf(p, "i915.%s=%d\n", name, val);
> +}
> +
> +static void _param_print_uint(struct drm_printer *p, const char *name,
> +			      unsigned int val)
> +{
> +	drm_printf(p, "i915.%s=%u\n", name, val);
> +}
> +
> +static void _param_print_ulong(struct drm_printer *p, const char *name,
> +			       unsigned long val)
> +{
> +	drm_printf(p, "i915.%s=%lu\n", name, val);
> +}
> +
> +static void _param_print_charp(struct drm_printer *p, const char *name,
> +			       const char *val)
> +{
> +	drm_printf(p, "i915.%s=%s\n", name, val);
> +}
> +
> +#define _param_print(p, name, val)				\
> +	_Generic(val,						\
> +		 bool: _param_print_bool,			\
> +		 int: _param_print_int,				\
> +		 unsigned int: _param_print_uint,		\
> +		 unsigned long: _param_print_ulong,		\
> +		 char *: _param_print_charp)(p, name, val)
> +
>  /**
>   * i915_params_dump - dump i915 modparams
>   * @params: i915 modparams
> @@ -252,7 +269,7 @@ static __always_inline void _print_param(struct drm_printer *p,
>   */
>  void i915_params_dump(const struct i915_params *params, struct drm_printer *p)
>  {
> -#define PRINT(T, x, ...) _print_param(p, #x, #T, &params->x);
> +#define PRINT(T, x, ...) _param_print(p, #x, params->x);
>  	I915_PARAMS_FOR_EACH(PRINT);
>  #undef PRINT
>  }