[patch 44/61] lock validator: special locking: waitqueues

[Ingo Molnar]

From: Ingo Molnar <mingo@xxxxxxx>

map special (multi-initialized) locking code to the lock validator.
Has no effect on non-lockdep kernels.

Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
---
---
 include/linux/wait.h |   11 +++++++++--
 kernel/wait.c        |    9 +++++++++
 2 files changed, 18 insertions(+), 2 deletions(-)

Index: linux/include/linux/wait.h
===================================================================
--- linux.orig/include/linux/wait.h
+++ linux/include/linux/wait.h
@@ -77,12 +77,19 @@ struct task_struct;
 #define __WAIT_BIT_KEY_INITIALIZER(word, bit)				\
 	{ .flags = word, .bit_nr = bit, }
 
-static inline void init_waitqueue_head(wait_queue_head_t *q)
+/*
+ * lockdep: we want one lock-type for all waitqueue locks.
+ */
+extern struct lockdep_type_key waitqueue_lock_key;
+
+static inline void __init_waitqueue_head(wait_queue_head_t *q)
 {
-	spin_lock_init(&q->lock);
+	spin_lock_init_key(&q->lock, &waitqueue_lock_key);
 	INIT_LIST_HEAD(&q->task_list);
 }
 
+extern void init_waitqueue_head(wait_queue_head_t *q);
+
 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
 {
 	q->flags = 0;
Index: linux/kernel/wait.c
===================================================================
--- linux.orig/kernel/wait.c
+++ linux/kernel/wait.c
@@ -11,6 +11,15 @@
 #include <linux/wait.h>
 #include <linux/hash.h>
 
+struct lockdep_type_key waitqueue_lock_key;
+
+void init_waitqueue_head(wait_queue_head_t *q)
+{
+	__init_waitqueue_head(q);
+}
+
+EXPORT_SYMBOL(init_waitqueue_head);
+
 void fastcall add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait)
 {
 	unsigned long flags;
-
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