From d5ec60bc0c2fa92a05e766463761b6e22d6d67b4 Mon Sep 17 00:00:00 2001
From: Gustavo Sverzut Barbieri <barbieri@profusion.mobi>
Date: Fri, 16 Dec 2011 22:32:33 -0200
Subject: [PATCH] introduce kmod_list_last()

This gets the last element in the list, that is, the previous element
of the head.
---
 libkmod/libkmod-list.c | 20 ++++++++++++++++++++
 libkmod/libkmod.h      |  2 ++
 libkmod/libkmod.sym    |  1 +
 3 files changed, 23 insertions(+)

diff --git a/libkmod/libkmod-list.c b/libkmod/libkmod-list.c
index 5ec33a2a..4b68b77e 100644
--- a/libkmod/libkmod-list.c
+++ b/libkmod/libkmod-list.c
@@ -310,3 +310,23 @@ KMOD_EXPORT struct kmod_list *kmod_list_next(const struct kmod_list *list,
 
 	return container_of(curr->node.next, struct kmod_list, node);
 }
+
+/**
+ * kmod_list_last:
+ * @list: the head of the list
+ *
+ * Get the last element of the @list. As @list is a circular list,
+ * this is a cheap operation O(1) with the last element being the
+ * previous element.
+ *
+ * If the list has a single element it will return the list itself (as
+ * expected, and this is what differentiates from kmod_list_prev()).
+ *
+ * Returns: last node at @list or NULL if the list is empty.
+ */
+KMOD_EXPORT struct kmod_list *kmod_list_last(const struct kmod_list *list)
+{
+	if (list == NULL)
+		return NULL;
+	return container_of(list->node.prev, struct kmod_list, node);
+}
diff --git a/libkmod/libkmod.h b/libkmod/libkmod.h
index 194946d1..37abbcc6 100644
--- a/libkmod/libkmod.h
+++ b/libkmod/libkmod.h
@@ -62,6 +62,8 @@ struct kmod_list *kmod_list_next(const struct kmod_list *first_entry,
 						const struct kmod_list *list_entry);
 struct kmod_list *kmod_list_prev(const struct kmod_list *first_entry,
 						const struct kmod_list *list_entry);
+struct kmod_list *kmod_list_last(const struct kmod_list *first_entry);
+
 #define kmod_list_foreach(list_entry, first_entry) \
 	for (list_entry = first_entry; \
 		list_entry != NULL; \
diff --git a/libkmod/libkmod.sym b/libkmod/libkmod.sym
index 71b7ccc8..664fd6bb 100644
--- a/libkmod/libkmod.sym
+++ b/libkmod/libkmod.sym
@@ -11,6 +11,7 @@ global:
 	kmod_unref;
 	kmod_list_next;
 	kmod_list_prev;
+        kmod_list_last;
 
 	kmod_load_resources;
 	kmod_unload_resources;
-- 
2.47.2