modpost: rework and consolidate logging interface

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. The purpose of this cleanup is
to reduce code duplication when deciding whether or not to warn or error
out based on a condition.

Signed-off-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/mod/modpost.h

@@ -198,6 +198,14 @@ void *grab_file(const char *filename, unsigned long *size);
 char* get_next_line(unsigned long *pos, void *file, unsigned long size);
 void release_file(void *file, unsigned long size);
 
-void fatal(const char *fmt, ...);
-void warn(const char *fmt, ...);
-void merror(const char *fmt, ...);
+enum loglevel {
+	LOG_WARN,
+	LOG_ERROR,
+	LOG_FATAL
+};
+
+void modpost_log(enum loglevel loglevel, const char *fmt, ...);
+
+#define warn(fmt, args...)	modpost_log(LOG_WARN, fmt, ##args)
+#define merror(fmt, args...)	modpost_log(LOG_ERROR, fmt, ##args)
+#define fatal(fmt, args...)	modpost_log(LOG_FATAL, fmt, ##args)