[PATCH 3.2 201/202] list: introduce list_first_entry_or_null
From: Ben Hutchings
Date: Sat Mar 11 2017 - 10:24:18 EST
3.2.87-rc2 review patch. If anyone has any objections, please let me know.
------------------
From: Jiri Pirko <jiri@xxxxxxxxxxx>
commit 6d7581e62f8be462440d7b22c6361f7c9fa4902b upstream.
non-rcu variant of list_first_or_null_rcu
Signed-off-by: Jiri Pirko <jiri@xxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
include/linux/list.h | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/include/linux/list.h b/include/linux/list.h
index 6a1f8df9144b..b83e5657365a 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -362,6 +362,17 @@ static inline void list_splice_tail_init(struct list_head *list,
list_entry((ptr)->next, 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_struct within the struct.
+ *
+ * Note that if the list is empty, it returns NULL.
+ */
+#define list_first_entry_or_null(ptr, type, member) \
+ (!list_empty(ptr) ? list_first_entry(ptr, 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.