menuconfig: Add "breadcrumbs" navigation aid

Displays a trail of the menu entries used to get to the current menu.

Signed-off-by: Benjamin Poirier <bpoirier@suse.de>
Tested-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
[yann.morin.1998@free.fr: small, trivial code re-ordering]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

1 files changed, 27 insertions, 0 deletions

diff --git a/scripts/kconfig/list.h b/scripts/kconfig/list.h
index b87206cc92f..ea1d58119d2 100644
--- a/scripts/kconfig/list.h
+++ b/scripts/kconfig/list.h
@@ -101,4 +101,31 @@ static inline void list_add_tail(struct list_head *_new, struct list_head *head)
 	__list_add(_new, head->prev, head);
 }
 
+/*
+ * Delete a list entry by making the prev/next entries
+ * point to each other.
+ *
+ * This is only for internal list manipulation where we know
+ * the prev/next entries already!
+ */
+static inline void __list_del(struct list_head *prev, struct list_head *next)
+{
+	next->prev = prev;
+	prev->next = next;
+}
+
+#define LIST_POISON1  ((void *) 0x00100100)
+#define LIST_POISON2  ((void *) 0x00200200)
+/**
+ * list_del - deletes entry from list.
+ * @entry: the element to delete from the list.
+ * Note: list_empty() on entry does not return true after this, the entry is
+ * in an undefined state.
+ */
+static inline void list_del(struct list_head *entry)
+{
+	__list_del(entry->prev, entry->next);
+	entry->next = LIST_POISON1;
+	entry->prev = LIST_POISON2;
+}
 #endif