locking/lockdep: Make it easy to detect whether or not inside a selftest

The patch that frees unused lock classes will modify the behavior of
lockdep_free_key_range() and lockdep_reset_lock() depending on whether
or not these functions are called from the context of the lockdep
selftests. Hence make it easy to detect whether or not lockdep code
is called from the context of a lockdep selftest.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: johannes.berg@intel.com
Cc: tj@kernel.org
Link: https://lkml.kernel.org/r/20190214230058.196511-10-bvanassche@acm.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index b5e6bfe0ae4a..66eee1ba0f2a 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -265,6 +265,7 @@ extern void lockdep_reset(void);
 extern void lockdep_reset_lock(struct lockdep_map *lock);
 extern void lockdep_free_key_range(void *start, unsigned long size);
 extern asmlinkage void lockdep_sys_exit(void);
+extern void lockdep_set_selftest_task(struct task_struct *task);
 
 extern void lockdep_off(void);
 extern void lockdep_on(void);
@@ -395,6 +396,10 @@ static inline void lockdep_on(void)
 {
 }
 
+static inline void lockdep_set_selftest_task(struct task_struct *task)
+{
+}
+
 # define lock_acquire(l, s, t, r, c, n, i)	do { } while (0)
 # define lock_release(l, n, i)			do { } while (0)
 # define lock_downgrade(l, i)			do { } while (0)