[3.16.y-ckt stable] Patch "locking: Add WARN_ON_ONCE lock assertion" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    locking: Add WARN_ON_ONCE lock assertion

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt22.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 02d4d9512faf2e50dfc426e1970a3471d70243e1 Mon Sep 17 00:00:00 2001
From: Peter Hurley <peter at hurleysoftware.com>
Date: Wed, 10 Sep 2014 14:31:39 -0400
Subject: locking: Add WARN_ON_ONCE lock assertion

commit 9a37110d20c95d1ebf6c04881177fe8f62831db2 upstream.

An interface may need to assert a lock invariant and not flood the
system logs; add a lockdep helper macro equivalent to
lockdep_assert_held() which only WARNs once.

Signed-off-by: Peter Hurley <peter at hurleysoftware.com>
Acked-by: Ingo Molnar <mingo at kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 include/linux/lockdep.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 008388f920d7..64c7425afbce 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -362,6 +362,10 @@ extern void lockdep_trace_alloc(gfp_t mask);
 		WARN_ON(debug_locks && !lockdep_is_held(l));	\
 	} while (0)

+#define lockdep_assert_held_once(l)	do {				\
+		WARN_ON_ONCE(debug_locks && !lockdep_is_held(l));	\
+	} while (0)
+
 #define lockdep_recursing(tsk)	((tsk)->lockdep_recursion)

 #else /* !CONFIG_LOCKDEP */
@@ -412,6 +416,7 @@ struct lock_class_key { };
 #define lockdep_depth(tsk)	(0)

 #define lockdep_assert_held(l)			do { (void)(l); } while (0)
+#define lockdep_assert_held_once(l)		do { (void)(l); } while (0)

 #define lockdep_recursing(tsk)			(0)