[PATCH] lockdep: add graph depth information to /proc/lockdep

Generate locking graph information into /proc/lockdep, for lock hierarchy
documentation and visualization purposes.

sample output:

 c089fd5c OPS:     138 FD:   14 BD:    1 --..: &tty->termios_mutex
  -> [c07a3430] tty_ldisc_lock
  -> [c07a37f0] &port_lock_key
  -> [c07afdc0] &rq->rq_lock_key#2

The lock classes listed are all the first-hop lock dependencies that
lockdep has seen so far.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index ea097dddc44f..7e1160dde5e7 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -132,6 +132,7 @@ struct lock_list {
         struct list_head                entry;
         struct lock_class               *class;
         struct stack_trace              trace;
+        int                             distance;
 };
 
 /*