[PATCH 2/3] kernel/workqueue: Surround work execution with shared lock annotations

[Bart Van Assche]

Surround execution of work with a shared lockdep annotation because multiple
work items associated with a work queue may execute concurrently.

Cc: Johannes Berg <johannes.berg@xxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Sagi Grimberg <sagi@xxxxxxxxxxx>
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
 kernel/workqueue.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 6755ef21a679..fc9129d5909e 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -2125,8 +2125,8 @@ __acquires(&pool->lock)
 
 	spin_unlock_irq(&pool->lock);
 
-	lock_map_acquire(&pwq->wq->lockdep_map);
-	lock_map_acquire(&lockdep_map);
+	lock_acquire_shared(&pwq->wq->lockdep_map, 0, 0, NULL, _THIS_IP_);
+	lock_acquire_shared(&lockdep_map, 0, 0, NULL, _THIS_IP_);
 	/*
 	 * Strictly speaking we should mark the invariant state without holding
 	 * any locks, that is, before these two lock_map_acquire()'s.
@@ -2156,8 +2156,8 @@ __acquires(&pool->lock)
 	 * point will only record its address.
 	 */
 	trace_workqueue_execute_end(work);
-	lock_map_release(&lockdep_map);
-	lock_map_release(&pwq->wq->lockdep_map);
+	lock_release(&lockdep_map, 0, _THIS_IP_);
+	lock_release(&pwq->wq->lockdep_map, 0, _THIS_IP_);
 
 	if (unlikely(in_atomic() || lockdep_depth(current) > 0)) {
 		pr_err("BUG: workqueue leaked lock or atomic: %s/0x%08x/%d\n"
@@ -2652,8 +2652,8 @@ void flush_workqueue(struct workqueue_struct *wq)
 	if (WARN_ON(!wq_online))
 		return;
 
-	lock_map_acquire(&wq->lockdep_map);
-	lock_map_release(&wq->lockdep_map);
+	lock_acquire_exclusive(&wq->lockdep_map, 0, 0, NULL, _THIS_IP_);
+	lock_release(&wq->lockdep_map, 0, _THIS_IP_);
 
 	mutex_lock(&wq->mutex);
 
@@ -2891,8 +2891,9 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr,
 	 */
 	if (!from_cancel &&
 	    (pwq->wq->saved_max_active == 1 || pwq->wq->rescuer)) {
-		lock_map_acquire(&pwq->wq->lockdep_map);
-		lock_map_release(&pwq->wq->lockdep_map);
+		lock_acquire_exclusive(&pwq->wq->lockdep_map, 0, 0, NULL,
+				       _THIS_IP_);
+		lock_release(&pwq->wq->lockdep_map, 0, _THIS_IP_);
 	}
 
 	return true;
-- 
2.19.1.568.g152ad8e336-goog