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commit 9022ada8ab6f1f1a932a3c93815061042e6548a5
parent 18b8bfdfbae5821a7df691bc1e542bbab6c31e9c
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Fri, 24 Aug 2018 13:16:36 -0700

Merge branch 'for-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

Pull workqueue updates from Tejun Heo:
 "Over the lockdep cross-release churn, workqueue lost some of the
  existing annotations. Johannes Berg restored it and also improved
  them"

* 'for-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: re-add lockdep dependencies for flushing
  workqueue: skip lockdep wq dependency in cancel_work_sync()

Diffstat:
Mkernel/workqueue.c | 45++++++++++++++++++++++++++++++---------------
1 file changed, 30 insertions(+), 15 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c @@ -2652,6 +2652,9 @@ 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); + mutex_lock(&wq->mutex); /* @@ -2843,7 +2846,8 @@ reflush: } EXPORT_SYMBOL_GPL(drain_workqueue); -static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr) +static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr, + bool from_cancel) { struct worker *worker = NULL; struct worker_pool *pool; @@ -2885,7 +2889,8 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr) * workqueues the deadlock happens when the rescuer stalls, blocking * forward progress. */ - if (pwq->wq->saved_max_active == 1 || pwq->wq->rescuer) { + 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); } @@ -2896,6 +2901,27 @@ already_gone: return false; } +static bool __flush_work(struct work_struct *work, bool from_cancel) +{ + struct wq_barrier barr; + + if (WARN_ON(!wq_online)) + return false; + + if (!from_cancel) { + lock_map_acquire(&work->lockdep_map); + lock_map_release(&work->lockdep_map); + } + + if (start_flush_work(work, &barr, from_cancel)) { + wait_for_completion(&barr.done); + destroy_work_on_stack(&barr.work); + return true; + } else { + return false; + } +} + /** * flush_work - wait for a work to finish executing the last queueing instance * @work: the work to flush @@ -2909,18 +2935,7 @@ already_gone: */ bool flush_work(struct work_struct *work) { - struct wq_barrier barr; - - if (WARN_ON(!wq_online)) - return false; - - if (start_flush_work(work, &barr)) { - wait_for_completion(&barr.done); - destroy_work_on_stack(&barr.work); - return true; - } else { - return false; - } + return __flush_work(work, false); } EXPORT_SYMBOL_GPL(flush_work); @@ -2986,7 +3001,7 @@ static bool __cancel_work_timer(struct work_struct *work, bool is_dwork) * isn't executing. */ if (wq_online) - flush_work(work); + __flush_work(work, true); clear_work_data(work);