patch-2.1.58 linux/include/linux/list.h

• Lines: 70
• Date: Sun Oct 12 10:46:27 1997
• Orig file: v2.1.57/linux/include/linux/list.h
• Orig date: Thu Jul 17 10:06:08 1997

diff -u --recursive --new-file v2.1.57/linux/include/linux/list.h linux/include/linux/list.h
@@ -3,7 +3,14 @@
 
 /*
  * Simple doubly linked list implementation.
+ *
+ * Some of the internal functions ("__xxx") are useful when
+ * manipulating whole lists rather than single entries, as
+ * sometimes we already know the next/prev entries and we can
+ * generate better code by using them directly rather than
+ * using the generic single-entry routines.
  */
+
 struct list_head {
 	struct list_head *next, *prev;
 };
@@ -15,22 +22,46 @@
 	(ptr)->next = (ptr); (ptr)->prev = (ptr); \
 } while (0)
 
-static inline void list_add(struct list_head *new, struct list_head *head)
+/*
+ * Insert a new entry between two known consecutive entries. 
+ *
+ * This is only for internal list manipulation where we know
+ * the prev/next entries already!
+ */
+static inline void __list_add(struct list_head * new,
+	struct list_head * prev,
+	struct list_head * next)
 {
-	struct list_head *next = head->next;
 	next->prev = new;
 	new->next = next;
-	new->prev = head;
-	head->next = new;
+	new->prev = prev;
+	prev->next = new;
 }
 
-static inline void list_del(struct list_head *entry)
+/*
+ * Insert a new entry after the specified head..
+ */
+static inline void list_add(struct list_head *new, struct list_head *head)
+{
+	__list_add(new, head, head->next);
+}
+
+/*
+ * 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)
 {
-	struct list_head *next, *prev;
-	next = entry->next;
-	prev = entry->prev;
 	next->prev = prev;
 	prev->next = next;
+}
+
+static inline void list_del(struct list_head *entry)
+{
+	__list_del(entry->prev, entry->next);
 }
 
 static inline int list_empty(struct list_head *head)