1 files changed, 63 insertions, 14 deletions

diff --git a/include/linux/list.h b/include/linux/list.h
index 29a375889fb8..09d979976b3b 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -20,8 +20,16 @@
  * using the generic single-entry routines.
  */
 
+/**
+ * LIST_HEAD_INIT - initialize a &struct list_head's links to point to itself
+ * @name: name of the list_head
+ */
 #define LIST_HEAD_INIT(name) { &(name), &(name) }
 
+/**
+ * LIST_HEAD - definition of a &struct list_head with initialization values
+ * @name: name of the list_head
+ */
 #define LIST_HEAD(name) \
 	struct list_head name = LIST_HEAD_INIT(name)
 
@@ -50,9 +58,9 @@ static inline void INIT_LIST_HEAD(struct list_head *list)
  * Performs the full set of list corruption checks before __list_add().
  * On list corruption reports a warning, and returns false.
  */
-extern bool __list_valid_slowpath __list_add_valid_or_report(struct list_head *new,
-							     struct list_head *prev,
-							     struct list_head *next);
+bool __list_valid_slowpath __list_add_valid_or_report(struct list_head *new,
+						      struct list_head *prev,
+						      struct list_head *next);
 
 /*
  * Performs list corruption checks before __list_add(). Returns false if a
@@ -93,7 +101,7 @@ static __always_inline bool __list_add_valid(struct list_head *new,
  * Performs the full set of list corruption checks before __list_del_entry().
  * On list corruption reports a warning, and returns false.
  */
-extern bool __list_valid_slowpath __list_del_entry_valid_or_report(struct list_head *entry);
+bool __list_valid_slowpath __list_del_entry_valid_or_report(struct list_head *entry);
 
 /*
  * Performs list corruption checks before __list_del_entry(). Returns false if a
@@ -183,6 +191,29 @@ static inline void list_add_tail(struct list_head *new, struct list_head *head)
 	__list_add(new, head->prev, head);
 }
 
+/**
+ * list_add_tail_release - add a new entry with release barrier
+ * @new: new entry to be added
+ * @head: list head to add it before
+ *
+ * Insert a new entry before the specified head, using a release barrier to set
+ * the ->next pointer that points to it.  This is useful for implementing
+ * queues, in particular one that the elements will be walked through forwards
+ * locklessly.
+ */
+static inline void list_add_tail_release(struct list_head *new,
+					 struct list_head *head)
+{
+	struct list_head *prev = head->prev;
+
+	if (__list_add_valid(new, prev, head)) {
+		new->next = head;
+		new->prev = prev;
+		head->prev = new;
+		smp_store_release(&prev->next, new);
+	}
+}
+
 /*
  * Delete a list entry by making the prev/next entries
  * point to each other.
@@ -637,6 +668,34 @@ static inline void list_splice_tail_init(struct list_head *list,
 })
 
 /**
+ * list_first_entry_or_null_acquire - get the first element from a list with barrier
+ * @ptr:	the list head to take the element from.
+ * @type:	the type of the struct this is embedded in.
+ * @member:	the name of the list_head within the struct.
+ *
+ * Note that if the list is empty, it returns NULL.
+ */
+#define list_first_entry_or_null_acquire(ptr, type, member) ({ \
+	struct list_head *head__ = (ptr); \
+	struct list_head *pos__ = smp_load_acquire(&head__->next); \
+	pos__ != head__ ? list_entry(pos__, type, member) : NULL; \
+})
+
+/**
+ * list_last_entry_or_null - get the last element from a list
+ * @ptr:	the list head to take the element from.
+ * @type:	the type of the struct this is embedded in.
+ * @member:	the name of the list_head within the struct.
+ *
+ * Note that if the list is empty, it returns NULL.
+ */
+#define list_last_entry_or_null(ptr, type, member) ({ \
+	struct list_head *head__ = (ptr); \
+	struct list_head *pos__ = READ_ONCE(head__->prev); \
+	pos__ != head__ ? list_entry(pos__, type, member) : NULL; \
+})
+
+/**
  * list_next_entry - get the next element in list
  * @pos:	the type * to cursor
  * @member:	the name of the list_head within the struct.
@@ -687,16 +746,6 @@ static inline void list_splice_tail_init(struct list_head *list,
 	for (pos = (head)->next; !list_is_head(pos, (head)); pos = pos->next)
 
 /**
- * list_for_each_rcu - Iterate over a list in an RCU-safe fashion
- * @pos:	the &struct list_head to use as a loop cursor.
- * @head:	the head for your list.
- */
-#define list_for_each_rcu(pos, head)		  \
-	for (pos = rcu_dereference((head)->next); \
-	     !list_is_head(pos, (head)); \
-	     pos = rcu_dereference(pos->next))
-
-/**
  * list_for_each_continue - continue iteration over a list
  * @pos:	the &struct list_head to use as a loop cursor.
  * @head:	the head for your list.