X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=include%2Flinux%2Flist.h;h=f62afa092c630bbd79e7f585a441dc6618a5c9b5;hb=6864fc8704661878294d1f0f981f47e864ef470f;hp=aeeeb21a12ddb481b9245681c752505ee661c6e4;hpb=ef0255fc75f28655f9681422079287d68a14dbaa;p=platform%2Fkernel%2Fu-boot.git

diff --git a/include/linux/list.h b/include/linux/list.h
index aeeeb21..f62afa0 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -338,13 +338,38 @@ static inline void list_splice_tail_init(struct list_head *list,
 	list_entry((ptr)->next, type, member)
 
 /**
+ * list_last_entry - 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_struct within the struct.
+ *
+ * Note, that list is expected to be not empty.
+ */
+#define list_last_entry(ptr, type, member) \
+	list_entry((ptr)->prev, type, member)
+
+/**
+ * list_first_entry_or_null - get the first 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_first_entry_or_null(ptr, type, member) ({ \
+	struct list_head *head__ = (ptr); \
+	struct list_head *pos__ = READ_ONCE(head__->next); \
+	pos__ != head__ ? list_entry(pos__, type, member) : NULL; \
+})
+
+/**
  * list_for_each	-	iterate over a list
  * @pos:	the &struct list_head to use as a loop cursor.
  * @head:	the head for your list.
  */
 #define list_for_each(pos, head) \
 	for (pos = (head)->next; prefetch(pos->next), pos != (head); \
-        	pos = pos->next)
+		pos = pos->next)
 
 /**
  * __list_for_each	-	iterate over a list
@@ -366,7 +391,7 @@ static inline void list_splice_tail_init(struct list_head *list,
  */
 #define list_for_each_prev(pos, head) \
 	for (pos = (head)->prev; prefetch(pos->prev), pos != (head); \
-        	pos = pos->prev)
+		pos = pos->prev)
 
 /**
  * list_for_each_safe - iterate over a list safe against removal of list entry
@@ -397,7 +422,7 @@ static inline void list_splice_tail_init(struct list_head *list,
  */
 #define list_for_each_entry(pos, head, member)				\
 	for (pos = list_entry((head)->next, typeof(*pos), member);	\
-	     prefetch(pos->member.next), &pos->member != (head); 	\
+	     prefetch(pos->member.next), &pos->member != (head);	\
 	     pos = list_entry(pos->member.next, typeof(*pos), member))
 
 /**
@@ -408,7 +433,7 @@ static inline void list_splice_tail_init(struct list_head *list,
  */
 #define list_for_each_entry_reverse(pos, head, member)			\
 	for (pos = list_entry((head)->prev, typeof(*pos), member);	\
-	     prefetch(pos->member.prev), &pos->member != (head); 	\
+	     prefetch(pos->member.prev), &pos->member != (head);	\
 	     pos = list_entry(pos->member.prev, typeof(*pos), member))
 
 /**
@@ -458,7 +483,7 @@ static inline void list_splice_tail_init(struct list_head *list,
  *
  * Iterate over list of given type, continuing from current position.
  */
-#define list_for_each_entry_from(pos, head, member) 			\
+#define list_for_each_entry_from(pos, head, member)			\
 	for (; prefetch(pos->member.next), &pos->member != (head);	\
 	     pos = list_entry(pos->member.next, typeof(*pos), member))
 
@@ -472,7 +497,7 @@ static inline void list_splice_tail_init(struct list_head *list,
 #define list_for_each_entry_safe(pos, n, head, member)			\
 	for (pos = list_entry((head)->next, typeof(*pos), member),	\
 		n = list_entry(pos->member.next, typeof(*pos), member);	\
-	     &pos->member != (head); 					\
+	     &pos->member != (head);					\
 	     pos = n, n = list_entry(n->member.next, typeof(*n), member))
 
 /**
@@ -486,7 +511,7 @@ static inline void list_splice_tail_init(struct list_head *list,
  * safe against removal of list entry.
  */
 #define list_for_each_entry_safe_continue(pos, n, head, member) 		\
-	for (pos = list_entry(pos->member.next, typeof(*pos), member), 		\
+	for (pos = list_entry(pos->member.next, typeof(*pos), member),		\
 		n = list_entry(pos->member.next, typeof(*pos), member);		\
 	     &pos->member != (head);						\
 	     pos = n, n = list_entry(n->member.next, typeof(*n), member))
@@ -501,7 +526,7 @@ static inline void list_splice_tail_init(struct list_head *list,
  * Iterate over list of given type from current point, safe against
  * removal of list entry.
  */
-#define list_for_each_entry_safe_from(pos, n, head, member) 			\
+#define list_for_each_entry_safe_from(pos, n, head, member)			\
 	for (n = list_entry(pos->member.next, typeof(*pos), member);		\
 	     &pos->member != (head);						\
 	     pos = n, n = list_entry(n->member.next, typeof(*n), member))
@@ -519,7 +544,7 @@ static inline void list_splice_tail_init(struct list_head *list,
 #define list_for_each_entry_safe_reverse(pos, n, head, member)		\
 	for (pos = list_entry((head)->prev, typeof(*pos), member),	\
 		n = list_entry(pos->member.prev, typeof(*pos), member);	\
-	     &pos->member != (head); 					\
+	     &pos->member != (head);					\
 	     pos = n, n = list_entry(n->member.prev, typeof(*n), member))
 
 /*
@@ -665,9 +690,9 @@ static inline void hlist_add_after(struct hlist_node *n,
  * @head:	the head for your list.
  * @member:	the name of the hlist_node within the struct.
  */
-#define hlist_for_each_entry_safe(tpos, pos, n, head, member) 		 \
+#define hlist_for_each_entry_safe(tpos, pos, n, head, member)		 \
 	for (pos = (head)->first;					 \
-	     pos && ({ n = pos->next; 1; }) && 				 \
+	     pos && ({ n = pos->next; 1; }) &&				 \
 		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
 	     pos = n)