Add generic list insert

1 files changed, 30 insertions, 0 deletions

diff --git a/include/linux/list.h b/include/linux/list.h
index 611059d633..e7d758c5fa 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -898,6 +898,36 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev,
                 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
              pos = pos->next)
 
+
+typedef int (*list_cmp_t)(struct list_head*, struct list_head*);
+
+static inline unsigned int list_insert(struct list_head* new,
+                                       struct list_head* head,
+                                       list_cmp_t is_less)
+{
+        struct list_head *pos;
+        unsigned int passed = 0;
+
+        BUG_ON(!new);
+
+        /* find a spot where the new entry is less than the next */
+        list_for_each(pos, head) {              
+                if (unlikely(is_less(new, pos))) {
+                        /* pos is not less than new, thus insert here */
+                        __list_add(new, pos->prev, pos);
+                        goto out;
+                }
+                passed++;
+        }
+        /* if we get to this point either the list is empty or every entry
+         * queued element is less than new.
+         * Let's add new to the end. */
+        list_add_tail(new, head);
+ out:
+        return passed;  
+}
+
+
 #else
 #warning "don't include kernel headers in userspace"
 #endif /* __KERNEL__ */