diff options
| -rw-r--r-- | kernel/workqueue.c | 40 |
1 files changed, 16 insertions, 24 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 1a442c301dd..251f0091429 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1068,6 +1068,7 @@ static int try_to_grab_pending(struct work_struct *work, bool is_dwork, unsigned long *flags) { struct worker_pool *pool; + struct cpu_workqueue_struct *cwq; local_irq_save(*flags); @@ -1097,14 +1098,17 @@ static int try_to_grab_pending(struct work_struct *work, bool is_dwork, goto fail; spin_lock(&pool->lock); - if (!list_empty(&work->entry)) { - /* - * This work is queued, but perhaps we locked the wrong - * pool. In that case we must see the new value after - * rmb(), see insert_work()->wmb(). - */ - smp_rmb(); - if (pool == get_work_pool(work)) { + /* + * work->data is guaranteed to point to cwq only while the work + * item is queued on cwq->wq, and both updating work->data to point + * to cwq on queueing and to pool on dequeueing are done under + * cwq->pool->lock. This in turn guarantees that, if work->data + * points to cwq which is associated with a locked pool, the work + * item is currently queued on that pool. + */ + cwq = get_work_cwq(work); + if (cwq) { + if (cwq->pool == pool) { debug_work_deactivate(work); /* @@ -1159,13 +1163,6 @@ static void insert_work(struct cpu_workqueue_struct *cwq, /* we own @work, set data and link */ set_work_cwq(work, cwq, extra_flags); - - /* - * Ensure that we get the right work->data if we see the - * result of list_add() below, see try_to_grab_pending(). - */ - smp_wmb(); - list_add_tail(&work->entry, head); /* @@ -2799,15 +2796,10 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr) return false; spin_lock_irq(&pool->lock); - if (!list_empty(&work->entry)) { - /* - * See the comment near try_to_grab_pending()->smp_rmb(). - * If it was re-queued to a different pool under us, we - * are not going to wait. - */ - smp_rmb(); - cwq = get_work_cwq(work); - if (unlikely(!cwq || pool != cwq->pool)) + /* see the comment in try_to_grab_pending() with the same code */ + cwq = get_work_cwq(work); + if (cwq) { + if (unlikely(cwq->pool != pool)) goto already_gone; } else { worker = find_worker_executing_work(pool, work); |