From: Eric Sandeen <sandeen@redhat.com>
Date: Fri, 27 Jun 2008 11:39:07 -0500
Subject: [fs] backport list_first_entry helper
Message-id: 486517AB.3010205@redhat.com
O-Subject: [PATCH RHEL5.3 1/3] backport list_first_entry helper
Bugzilla: 449668
RH-Acked-by: Jeff Moyer <jmoyer@redhat.com>
RH-Acked-by: Jarod Wilson <jwilson@redhat.com>

For BZ 449668: RHEL5.3: update ecryptfs kernelspace to 2.6.26 codebase

Backport the list_first_entry helper which ecryptfs would like to use.

Thanks,
-Eric

(list.h changes only)

From: Pavel Emelianov <xemul@sw.ru>
Date: Tue, 8 May 2007 07:30:19 +0000 (-0700)
Subject: Introduce a handy list_first_entry macro
X-Git-Tag: v2.6.22-rc1~643
X-Git-Url: http://git.engineering.redhat.com/?p=linux-2.6.git;a=commitdiff_plain;h=b5e618181a927210f8be1d3d2249d31904ba358d

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>

diff --git a/include/linux/list.h b/include/linux/list.h
index 3e953c5..0d114ba 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -425,6 +425,17 @@ 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.