From f4d3fddb570141aa2edb4e9d06949237518e45ab Mon Sep 17 00:00:00 2001
From: Frederic Weisbecker <frederic@kernel.org>
Date: Mon, 6 Nov 2017 16:01:17 +0100
Subject: [PATCH] locking/lockdep: Add IRQs disabled/enabled assertion APIs:
 lockdep_assert_irqs_enabled()/disabled()

References: bnc#1068202 Avoid irqs_disabled debugging checks in fast paths
Patch-mainline: v4.15-rc1
Git-commit: f54bb2ec02c839f6bfe3e8d438cd93d30b4809dd

Checking whether IRQs are enabled or disabled is a very common sanity
check, however not free of overhead especially on fastpath where such
assertion is very common.

Lockdep is a good host for such concurrency correctness check and it
even already tracks down IRQs disablement state. Just reuse its
machinery. This will allow us to get rid of the flags pop and check
overhead from fast path when kernel is built for production.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: David S . Miller <davem@davemloft.net>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/1509980490-4285-2-git-send-email-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
 include/linux/lockdep.h | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index fffe49f188e6..0125a04ed343 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -586,9 +586,24 @@ do {									\
 	lock_acquire(&(lock)->dep_map, 0, 0, 1, 1, NULL, _THIS_IP_);	\
 	lock_release(&(lock)->dep_map, 0, _THIS_IP_);			\
 } while (0)
+
+#define lockdep_assert_irqs_enabled()	do {				\
+		WARN_ONCE(debug_locks && !current->lockdep_recursion &&	\
+			  !current->hardirqs_enabled,			\
+			  "IRQs not enabled as expected\n");		\
+	} while (0)
+
+#define lockdep_assert_irqs_disabled()	do {				\
+		WARN_ONCE(debug_locks && !current->lockdep_recursion &&	\
+			  current->hardirqs_enabled,			\
+			  "IRQs not disabled as expected\n");		\
+	} while (0)
+
 #else
 # define might_lock(lock) do { } while (0)
 # define might_lock_read(lock) do { } while (0)
+# define lockdep_assert_irqs_enabled() do { } while (0)
+# define lockdep_assert_irqs_disabled() do { } while (0)
 #endif
 
 #ifdef CONFIG_LOCKDEP