lockdep/waitqueues: Add better annotation

 -> #2 (&tty->write_wait){-.-...}:

is a lot more informative than:

 -> #2 (key#19){-.....}:

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-8zpopbny51023rdb0qq67eye@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 4 insertions, 4 deletions

diff --git a/include/linux/wait.h b/include/linux/wait.h
index 3efc9f3f43a0..a9ce45e8501c 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -77,13 +77,13 @@ struct task_struct;
 #define __WAIT_BIT_KEY_INITIALIZER(word, bit)                           \
         { .flags = word, .bit_nr = bit, }
 
-extern void __init_waitqueue_head(wait_queue_head_t *q, struct lock_class_key *);
+extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *);
 
 #define init_waitqueue_head(q)                          \
         do {                                            \
                 static struct lock_class_key __key;     \
                                                         \
-                __init_waitqueue_head((q), &__key);     \
+                __init_waitqueue_head((q), #q, &__key); \
         } while (0)
 
 #ifdef CONFIG_LOCKDEP
diff --git a/kernel/wait.c b/kernel/wait.c
index 26fa7797f90f..7fdd9eaca2c3 100644
--- a/kernel/wait.c
+++ b/kernel/wait.c
@@ -10,10 +10,10 @@
 #include <linux/wait.h>
 #include <linux/hash.h>
 
-void __init_waitqueue_head(wait_queue_head_t *q, struct lock_class_key *key)
+void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *key)
 {
         spin_lock_init(&q->lock);
-        lockdep_set_class(&q->lock, key);
+        lockdep_set_class_and_name(&q->lock, key, name);
         INIT_LIST_HEAD(&q->task_list);
 }