params: Introduce the param_unknown_fn type

Introduce a new type for the callback to parse an unknown argument.
This unifies function prototypes which takes that as a parameter.

Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20231120151419.1661807-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Kees Cook <keescook@chromium.org>

Author: andy-shev

include/linux/moduleparam.h

@@ -385,16 +385,16 @@ extern bool parameq(const char *name1, const char *name2);
  */
 extern bool parameqn(const char *name1, const char *name2, size_t n);
 
+typedef int (*parse_unknown_fn)(char *param, char *val, const char *doing, void *arg);
+
 /* Called on module insert or kernel boot */
 extern char *parse_args(const char *name,
 		      char *args,
 		      const struct kernel_param *params,
 		      unsigned num,
 		      s16 level_min,
 		      s16 level_max,
-		      void *arg,
-		      int (*unknown)(char *param, char *val,
-				     const char *doing, void *arg));
+		      void *arg, parse_unknown_fn unknown);
 
 /* Called by module remove. */
 #ifdef CONFIG_SYSFS

kernel/params.c

@@ -120,9 +120,7 @@ static int parse_one(char *param,
 		     unsigned num_params,
 		     s16 min_level,
 		     s16 max_level,
-		     void *arg,
-		     int (*handle_unknown)(char *param, char *val,
-				     const char *doing, void *arg))
+		     void *arg, parse_unknown_fn handle_unknown)
 {
 	unsigned int i;
 	int err;
@@ -165,9 +163,7 @@ char *parse_args(const char *doing,
 		 unsigned num,
 		 s16 min_level,
 		 s16 max_level,
-		 void *arg,
-		 int (*unknown)(char *param, char *val,
-				const char *doing, void *arg))
+		 void *arg, parse_unknown_fn unknown)
 {
 	char *param, *val, *err = NULL;