lkml.org 
[lkml]   [2013]   [Nov]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH 1/6] list: introduce list_last_entry_or_null()
From: Jie Liu <jeff.liu@oracle.com>

Introduce a trivial helper list_last_entry_or_null() to fetch the
last entry from a list, return NULL if the list is empty.

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
---
include/linux/list.h | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/include/linux/list.h b/include/linux/list.h
index ef95941..3337249 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -384,6 +384,17 @@ static inline void list_splice_tail_init(struct list_head *list,
(!list_empty(ptr) ? list_first_entry(ptr, 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_struct within the struct.
+ *
+ * Note that if the list is empty, it returns NULL.
+ */
+#define list_last_entry_or_null(ptr, type, member) \
+ (!list_empty(ptr) ? list_last_entry(ptr, type, member) : NULL)
+
+/**
* list_next_entry - get the next element in list
* @pos: the type * to cursor
* @member: the name of the list_struct within the struct.
--
1.8.3.2

\
 
 \ /
  Last update: 2013-11-15 05:41    [W:0.024 / U:1.436 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site