lockdep: spin_lock_nest_lock()

Expose the new lock protection lock.

This can be used to annotate places where we take multiple locks of the
same class and avoid deadlocks by always taking another (top-level) lock
first.

NOTE: we're still bound to the MAX_LOCK_DEPTH (48) limit.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 93a8cc02a033..4452c04a7f6e 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -410,8 +410,10 @@ static inline void print_irqtrace_events(struct task_struct *curr)
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 # ifdef CONFIG_PROVE_LOCKING
 #  define spin_acquire(l, s, t, i)              lock_acquire(l, s, t, 0, 2, NULL, i)
+#  define spin_acquire_nest(l, s, t, n, i)      lock_acquire(l, s, t, 0, 2, n, i)
 # else
 #  define spin_acquire(l, s, t, i)              lock_acquire(l, s, t, 0, 1, NULL, i)
+#  define spin_acquire_nest(l, s, t, n, i)      lock_acquire(l, s, t, 0, 1, NULL, i)
 # endif
 # define spin_release(l, n, i)                  lock_release(l, n, i)
 #else