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authorPavel Emelianov <xemul@sw.ru>2007-05-08 00:30:19 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-08 11:15:11 -0700
commitb5e618181a927210f8be1d3d2249d31904ba358d (patch)
tree731f1ae4ff1ba56d402bb329182b7d935bb439a1 /include/linux/list.h
parentdb9c02fa8bd50eb104781a9f78cae923d8da1e74 (diff)
Introduce a handy list_first_entry macro
There are many places in the kernel where the construction like foo = list_entry(head->next, struct foo_struct, list); are used. The code might look more descriptive and neat if using the macro list_first_entry(head, type, member) \ list_entry((head)->next, type, member) Here is the macro itself and the examples of its usage in the generic code. If it will turn out to be useful, I can prepare the set of patches to inject in into arch-specific code, drivers, networking, etc. Signed-off-by: Pavel Emelianov <xemul@openvz.org> Signed-off-by: Kirill Korotaev <dev@openvz.org> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Zach Brown <zach.brown@oracle.com> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: John McCutchan <ttb@tentacle.dhs.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: john stultz <johnstul@us.ibm.com> Cc: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/list.h')
-rw-r--r--include/linux/list.h11
1 files changed, 11 insertions, 0 deletions
diff --git a/include/linux/list.h b/include/linux/list.h
index f9d71eab05ee..9202703be2a4 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -426,6 +426,17 @@ static inline void list_splice_init_rcu(struct list_head *list,
container_of(ptr, type, member)
/**
+ * list_first_entry - 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 list is expected to be not empty.
+ */
+#define list_first_entry(ptr, type, member) \
+ list_entry((ptr)->next, type, member)
+
+/**
* list_for_each - iterate over a list
* @pos: the &struct list_head to use as a loop cursor.
* @head: the head for your list.