module: Add helper function for reading module_buildid()

Add a helper function for reading the optional "build_id" member
of struct module. It is going to be used also in
ftrace_mod_address_lookup().

Use "#ifdef" instead of "#if IS_ENABLED()" to match the declaration
of the optional field in struct module.

Reviewed-by: Daniel Gomez <[email protected]>
Reviewed-by: Petr Pavlu <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>

Author: pmladek

include/linux/module.h

@@ -747,6 +747,15 @@ static inline void __module_get(struct module *module)
 	__mod ? __mod->name : "kernel";		\
 })
 
+static inline const unsigned char *module_buildid(struct module *mod)
+{
+#ifdef CONFIG_STACKTRACE_BUILD_ID
+	return mod->build_id;
+#else
+	return NULL;
+#endif
+}
+
 /* Dereference module function descriptor */
 void *dereference_module_function_descriptor(struct module *mod, void *ptr);
 

kernel/module/kallsyms.c

@@ -334,13 +334,8 @@ int module_address_lookup(unsigned long addr,
 	if (mod) {
 		if (modname)
 			*modname = mod->name;
-		if (modbuildid) {
-#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
-			*modbuildid = mod->build_id;
-#else
-			*modbuildid = NULL;
-#endif
-		}
+		if (modbuildid)
+			*modbuildid = module_buildid(mod);
 
 		sym = find_kallsyms_symbol(mod, addr, size, offset);