Re: [PATCH 1/2] modpost: rework and consolidate logging interface

[Joe Perches <joe@perches.com>]

On Tue, 2020-02-25 at 18:35 +0100, Jessica Yu wrote:
> Rework modpost's logging interface by consolidating merror(), warn(),
> and fatal() to use a single function, modpost_log(). Introduce different
> logging levels (WARN, ERROR, FATAL) as well as a conditional warn
> (warn_unless()). The conditional warn is useful in determining whether
> to use merror() or warn() based on a condition. This reduces code
> duplication overall.
[]
> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
[]
> @@ -51,41 +51,39 @@ enum export {
>  
>  #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
>  
> -#define PRINTF __attribute__ ((format (printf, 1, 2)))
> +#define PRINTF __attribute__ ((format (printf, 2, 3)))
>  
> -PRINTF void fatal(const char *fmt, ...)
> +PRINTF void modpost_log(enum loglevel loglevel, const char *fmt, ...)
>  {
> +	char *level = NULL;
>  	va_list arglist;
>  
> -	fprintf(stderr, "FATAL: ");
> +	switch(loglevel) {
> +	case(LOG_WARN):
> +		level = "WARNING: ";
> +		break;
> +	case(LOG_ERROR):
> +		level = "ERROR: ";
> +		break;
> +	case(LOG_FATAL):
> +		level = "FATAL: ";
> +		break;
> +	default: /* invalid loglevel, ignore */
> +		break;

Odd parentheses around case labels and
likely level should be initialized as ""
and not NULL.

	const char *level = "";
	...
	switch (loglevel) {
	case LOG_WARN:
		level = "WARNING: ";
		break;
	...
	}