Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfs

[net-next-2.6.git] / include / linux / list.h

diff --git a/include/linux/list.h b/include/linux/list.h
index 8392884a2977cda6a5f004fed2511ad51a140aa5..5d57a3a1fa1b1b9143a5e80381ac7668b51bb677 100644 (file)
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -544,6 +544,21 @@ static inline void list_splice_tail_init(struct list_head *list,
             &pos->member != (head);                                    \
             pos = n, n = list_entry(n->member.prev, typeof(*n), member))
 
+/**
+ * list_safe_reset_next - reset a stale list_for_each_entry_safe loop
+ * @pos:       the loop cursor used in the list_for_each_entry_safe loop
+ * @n:         temporary storage used in list_for_each_entry_safe
+ * @member:    the name of the list_struct within the struct.
+ *
+ * list_safe_reset_next is not safe to use in general if the list may be
+ * modified concurrently (eg. the lock is dropped in the loop body). An
+ * exception to this is if the cursor element (pos) is pinned in the list,
+ * and list_safe_reset_next is called after re-taking the lock and before
+ * completing the current iteration of the loop body.
+ */
+#define list_safe_reset_next(pos, n, member)                           \
+       n = list_entry(pos->member.next, typeof(*pos), member)
+
 /*
  * Double linked lists with a single pointer list head.
  * Mostly useful for hash tables where the two pointer list head is