diff options
| -rw-r--r-- | kernel/workqueue.c | 62 |
1 files changed, 41 insertions, 21 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 189d79be8091..c458d73022bb 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -163,6 +163,7 @@ struct worker_pool { struct mutex manager_arb; /* manager arbitration */ struct mutex manager_mutex; /* manager exclusion */ struct idr worker_idr; /* M: worker IDs and iteration */ + struct completion *detach_completion; /* all workers detached */ struct workqueue_attrs *attrs; /* I: worker attributes */ struct hlist_node hash_node; /* PL: unbound_pool_hash node */ @@ -1688,6 +1689,30 @@ static struct worker *alloc_worker(void) } /** + * worker_detach_from_pool() - detach a worker from its pool + * @worker: worker which is attached to its pool + * @pool: the pool @worker is attached to + * + * Undo the attaching which had been done in create_worker(). The caller + * worker shouldn't access to the pool after detached except it has other + * reference to the pool. + */ +static void worker_detach_from_pool(struct worker *worker, + struct worker_pool *pool) +{ + struct completion *detach_completion = NULL; + + mutex_lock(&pool->manager_mutex); + idr_remove(&pool->worker_idr, worker->id); + if (idr_is_empty(&pool->worker_idr)) + detach_completion = pool->detach_completion; + mutex_unlock(&pool->manager_mutex); + + if (detach_completion) + complete(detach_completion); +} + +/** * create_worker - create a new workqueue worker * @pool: pool the new worker will belong to * @@ -1815,13 +1840,12 @@ static int create_and_start_worker(struct worker_pool *pool) * be idle. * * CONTEXT: - * spin_lock_irq(pool->lock) which is released and regrabbed. + * spin_lock_irq(pool->lock). */ static void destroy_worker(struct worker *worker) { struct worker_pool *pool = worker->pool; - lockdep_assert_held(&pool->manager_mutex); lockdep_assert_held(&pool->lock); /* sanity check frenzy */ @@ -1833,24 +1857,9 @@ static void destroy_worker(struct worker *worker) pool->nr_workers--; pool->nr_idle--; - /* - * Once WORKER_DIE is set, the kworker may destroy itself at any - * point. Pin to ensure the task stays until we're done with it. - */ - get_task_struct(worker->task); - list_del_init(&worker->entry); worker->flags |= WORKER_DIE; - - idr_remove(&pool->worker_idr, worker->id); - - spin_unlock_irq(&pool->lock); - - kthread_stop(worker->task); - put_task_struct(worker->task); - kfree(worker); - - spin_lock_irq(&pool->lock); + wake_up_process(worker->task); } static void idle_worker_timeout(unsigned long __pool) @@ -2289,6 +2298,10 @@ woke_up: spin_unlock_irq(&pool->lock); WARN_ON_ONCE(!list_empty(&worker->entry)); worker->task->flags &= ~PF_WQ_WORKER; + + set_task_comm(worker->task, "kworker/dying"); + worker_detach_from_pool(worker, pool); + kfree(worker); return 0; } @@ -3560,6 +3573,7 @@ static void rcu_free_pool(struct rcu_head *rcu) */ static void put_unbound_pool(struct worker_pool *pool) { + DECLARE_COMPLETION_ONSTACK(detach_completion); struct worker *worker; lockdep_assert_held(&wq_pool_mutex); @@ -3583,15 +3597,21 @@ static void put_unbound_pool(struct worker_pool *pool) * manager_mutex. */ mutex_lock(&pool->manager_arb); - mutex_lock(&pool->manager_mutex); - spin_lock_irq(&pool->lock); + spin_lock_irq(&pool->lock); while ((worker = first_worker(pool))) destroy_worker(worker); WARN_ON(pool->nr_workers || pool->nr_idle); - spin_unlock_irq(&pool->lock); + + mutex_lock(&pool->manager_mutex); + if (!idr_is_empty(&pool->worker_idr)) + pool->detach_completion = &detach_completion; mutex_unlock(&pool->manager_mutex); + + if (pool->detach_completion) + wait_for_completion(pool->detach_completion); + mutex_unlock(&pool->manager_arb); /* shut down the timers */ |