Re: [PATCH v2 1/3] lib/vsprintf: Avoid redundant work with 0 size

[Sergey Senozhatsky <senozhatsky-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>]

On (22/01/29 15:53), Waiman Long wrote:
> For *scnprintf(), vsnprintf() is always called even if the input size is
> 0. That is a waste of time, so just return 0 in this case.
> 
> Signed-off-by: Waiman Long <longman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

Reviewed-by: Sergey Senozhatsky <senozhatsky-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>


> +++ b/lib/vsprintf.c
> @@ -2895,13 +2895,15 @@ int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
>  {
>  	int i;
>  
> +	if (!size)
> +		return 0;
> +
>  	i = vsnprintf(buf, size, fmt, args);
>  
>  	if (likely(i < size))
>  		return i;
> -	if (size != 0)
> -		return size - 1;
> -	return 0;
> +
> +	return size - 1;
>  }
>  EXPORT_SYMBOL(vscnprintf);