kconfig: change file_lookup() to return the file name

Currently, file_lookup() returns a pointer to (struct file), but the
callers use only file->name.

Make it return the ->name member directly.

This adjustment encapsulates struct file and file_list as internal
implementation.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/kconfig/expr.h

@@ -17,11 +17,6 @@ extern "C" {
 #include <stdbool.h>
 #endif
 
-struct file {
-	struct file *next;
-	char name[];
-};
-
 typedef enum tristate {
 	no, mod, yes
 } tristate;
@@ -275,8 +270,6 @@ struct jump_key {
 	struct menu *target;
 };
 
-extern struct file *file_list;
-
 extern struct symbol symbol_yes, symbol_no, symbol_mod;
 extern struct symbol *modules_sym;
 extern int cdebug;

scripts/kconfig/lexer.l

@@ -401,13 +401,12 @@ void zconf_initscan(const char *name)
 		exit(1);
 	}
 
-	cur_filename = file_lookup(name)->name;
+	cur_filename = file_lookup(name);
 	yylineno = 1;
 }
 
 void zconf_nextfile(const char *name)
 {
-	struct file *file = file_lookup(name);
 	struct buffer *buf = xmalloc(sizeof(*buf));
 	bool recur_include = false;
 
@@ -443,7 +442,7 @@ void zconf_nextfile(const char *name)
 	}
 
 	yylineno = 1;
-	cur_filename = file->name;
+	cur_filename = file_lookup(name);
 }
 
 static void zconf_endfile(void)

scripts/kconfig/lkc.h

@@ -52,7 +52,7 @@ static inline void xfwrite(const void *str, size_t len, size_t count, FILE *out)
 }
 
 /* util.c */
-struct file *file_lookup(const char *name);
+const char *file_lookup(const char *name);
 void *xmalloc(size_t size);
 void *xcalloc(size_t nmemb, size_t size);
 void *xrealloc(void *p, size_t size);

scripts/kconfig/menu.c

@@ -16,8 +16,6 @@ static const char nohelp_text[] = "There is no help available for this option.";
 struct menu rootmenu;
 static struct menu **last_entry_ptr;
 
-struct file *file_list;
-
 void menu_warn(struct menu *menu, const char *fmt, ...)
 {
 	va_list ap;

scripts/kconfig/util.c

@@ -9,15 +9,22 @@
 #include <string.h>
 #include "lkc.h"
 
+struct file {
+	struct file *next;
+	char name[];
+};
+
+static struct file *file_list;
+
 /* file already present in list? If not add it */
-struct file *file_lookup(const char *name)
+const char *file_lookup(const char *name)
 {
 	struct file *file;
 	size_t len;
 
 	for (file = file_list; file; file = file->next) {
 		if (!strcmp(name, file->name)) {
-			return file;
+			return file->name;
 		}
 	}
 
@@ -31,7 +38,7 @@ struct file *file_lookup(const char *name)
 
 	str_printf(&autoconf_cmd, "\t%s \\\n", name);
 
-	return file;
+	return file->name;
 }
 
 /* Allocate initial growable string */