kconfig: link menus to a symbol

Currently, there is no direct link from (struct symbol) to (struct menu).

It is still possible to access associated menus through the P_SYMBOL
property, because property::menu is the relevant menu entry, but it
results in complex code, as seen in get_symbol_str().

Use a linked list for simpler traversal of relevant menus.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

scripts/kconfig/expr.h

@@ -108,6 +108,9 @@ struct symbol {
 	 */
 	tristate visible;
 
+	/* config entries associated with this symbol */
+	struct list_head menus;
+
 	/* SYMBOL_* flags */
 	int flags;
 
@@ -222,6 +225,8 @@ struct menu {
 	 */
 	struct symbol *sym;
 
+	struct list_head link;	/* link to symbol::menus */
+
 	/*
 	 * The prompt associated with the node. This holds the prompt for a
 	 * symbol as well as the text for a menu or comment, along with the

scripts/kconfig/menu.c

@@ -57,8 +57,10 @@ void menu_add_entry(struct symbol *sym)
 	*last_entry_ptr = menu;
 	last_entry_ptr = &menu->next;
 	current_entry = menu;
-	if (sym)
+	if (sym) {
 		menu_add_symbol(P_SYMBOL, sym, NULL);
+		list_add_tail(&menu->link, &sym->menus);
+	}
 }
 
 struct menu *menu_add_menu(void)

scripts/kconfig/symbol.c

@@ -15,18 +15,21 @@
 struct symbol symbol_yes = {
 	.name = "y",
 	.curr = { "y", yes },
+	.menus = LIST_HEAD_INIT(symbol_yes.menus),
 	.flags = SYMBOL_CONST|SYMBOL_VALID,
 };
 
 struct symbol symbol_mod = {
 	.name = "m",
 	.curr = { "m", mod },
+	.menus = LIST_HEAD_INIT(symbol_mod.menus),
 	.flags = SYMBOL_CONST|SYMBOL_VALID,
 };
 
 struct symbol symbol_no = {
 	.name = "n",
 	.curr = { "n", no },
+	.menus = LIST_HEAD_INIT(symbol_no.menus),
 	.flags = SYMBOL_CONST|SYMBOL_VALID,
 };
 
@@ -838,6 +841,7 @@ struct symbol *sym_lookup(const char *name, int flags)
 	symbol->name = new_name;
 	symbol->type = S_UNKNOWN;
 	symbol->flags = flags;
+	INIT_LIST_HEAD(&symbol->menus);
 
 	hash_add(sym_hashtable, &symbol->node, hash);