Merge tag 'v4.17-rc3' into apparmor-next

Linux v4.17-rc3

Merge in v4.17 for LSM updates

Signed-off-by: John Johansen <john.johansen@canonical.com>

1 files changed, 117 insertions, 39 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index f699122dab32..ca7959be8aaa 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -153,10 +153,9 @@ struct worker_pool {
 	unsigned long		watchdog_ts;	/* L: watchdog timestamp */
 
 	struct list_head	worklist;	/* L: list of pending works */
-	int			nr_workers;	/* L: total number of workers */
 
-	/* nr_idle includes the ones off idle_list for rebinding */
-	int			nr_idle;	/* L: currently idle ones */
+	int			nr_workers;	/* L: total number of workers */
+	int			nr_idle;	/* L: currently idle workers */
 
 	struct list_head	idle_list;	/* X: list of idle workers */
 	struct timer_list	idle_timer;	/* L: worker idle timeout */
@@ -166,7 +165,6 @@ struct worker_pool {
 	DECLARE_HASHTABLE(busy_hash, BUSY_WORKER_HASH_ORDER);
 						/* L: hash of busy workers */
 
-	/* see manage_workers() for details on the two manager mutexes */
 	struct worker		*manager;	/* L: purely informational */
 	struct mutex		attach_mutex;	/* attach/detach exclusion */
 	struct list_head	workers;	/* A: attached workers */
@@ -1604,6 +1602,40 @@ bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
 }
 EXPORT_SYMBOL_GPL(mod_delayed_work_on);
 
+static void rcu_work_rcufn(struct rcu_head *rcu)
+{
+	struct rcu_work *rwork = container_of(rcu, struct rcu_work, rcu);
+
+	/* read the comment in __queue_work() */
+	local_irq_disable();
+	__queue_work(WORK_CPU_UNBOUND, rwork->wq, &rwork->work);
+	local_irq_enable();
+}
+
+/**
+ * queue_rcu_work - queue work after a RCU grace period
+ * @wq: workqueue to use
+ * @rwork: work to queue
+ *
+ * Return: %false if @rwork was already pending, %true otherwise.  Note
+ * that a full RCU grace period is guaranteed only after a %true return.
+ * While @rwork is guarnateed to be executed after a %false return, the
+ * execution may happen before a full RCU grace period has passed.
+ */
+bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork)
+{
+	struct work_struct *work = &rwork->work;
+
+	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
+		rwork->wq = wq;
+		call_rcu(&rwork->rcu, rcu_work_rcufn);
+		return true;
+	}
+
+	return false;
+}
+EXPORT_SYMBOL(queue_rcu_work);
+
 /**
  * worker_enter_idle - enter idle state
  * @worker: worker which is entering idle state
@@ -2136,7 +2168,7 @@ __acquires(&pool->lock)
 	 * stop_machine. At the same time, report a quiescent RCU state so
 	 * the same condition doesn't freeze RCU.
 	 */
-	cond_resched_rcu_qs();
+	cond_resched();
 
 	spin_lock_irq(&pool->lock);
 
@@ -3001,6 +3033,26 @@ bool flush_delayed_work(struct delayed_work *dwork)
 }
 EXPORT_SYMBOL(flush_delayed_work);
 
+/**
+ * flush_rcu_work - wait for a rwork to finish executing the last queueing
+ * @rwork: the rcu work to flush
+ *
+ * Return:
+ * %true if flush_rcu_work() waited for the work to finish execution,
+ * %false if it was already idle.
+ */
+bool flush_rcu_work(struct rcu_work *rwork)
+{
+	if (test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&rwork->work))) {
+		rcu_barrier();
+		flush_work(&rwork->work);
+		return true;
+	} else {
+		return flush_work(&rwork->work);
+	}
+}
+EXPORT_SYMBOL(flush_rcu_work);
+
 static bool __cancel_work(struct work_struct *work, bool is_dwork)
 {
 	unsigned long flags;
@@ -3018,14 +3070,6 @@ static bool __cancel_work(struct work_struct *work, bool is_dwork)
 	return ret;
 }
 
-/*
- * See cancel_delayed_work()
- */
-bool cancel_work(struct work_struct *work)
-{
-	return __cancel_work(work, false);
-}
-
 /**
  * cancel_delayed_work - cancel a delayed work
  * @dwork: delayed_work to cancel
@@ -3807,6 +3851,7 @@ int apply_workqueue_attrs(struct workqueue_struct *wq,
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(apply_workqueue_attrs);
 
 /**
  * wq_update_unbound_numa - update NUMA affinity of a wq for CPU hot[un]plug
@@ -3940,6 +3985,37 @@ static int wq_clamp_max_active(int max_active, unsigned int flags,
 	return clamp_val(max_active, 1, lim);
 }
 
+/*
+ * Workqueues which may be used during memory reclaim should have a rescuer
+ * to guarantee forward progress.
+ */
+static int init_rescuer(struct workqueue_struct *wq)
+{
+	struct worker *rescuer;
+	int ret;
+
+	if (!(wq->flags & WQ_MEM_RECLAIM))
+		return 0;
+
+	rescuer = alloc_worker(NUMA_NO_NODE);
+	if (!rescuer)
+		return -ENOMEM;
+
+	rescuer->rescue_wq = wq;
+	rescuer->task = kthread_create(rescuer_thread, rescuer, "%s", wq->name);
+	ret = PTR_ERR_OR_ZERO(rescuer->task);
+	if (ret) {
+		kfree(rescuer);
+		return ret;
+	}
+
+	wq->rescuer = rescuer;
+	kthread_bind_mask(rescuer->task, cpu_possible_mask);
+	wake_up_process(rescuer->task);
+
+	return 0;
+}
+
 struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
 					       unsigned int flags,
 					       int max_active,
@@ -4002,29 +4078,8 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
 	if (alloc_and_link_pwqs(wq) < 0)
 		goto err_free_wq;
 
-	/*
-	 * Workqueues which may be used during memory reclaim should
-	 * have a rescuer to guarantee forward progress.
-	 */
-	if (flags & WQ_MEM_RECLAIM) {
-		struct worker *rescuer;
-
-		rescuer = alloc_worker(NUMA_NO_NODE);
-		if (!rescuer)
-			goto err_destroy;
-
-		rescuer->rescue_wq = wq;
-		rescuer->task = kthread_create(rescuer_thread, rescuer, "%s",
-					       wq->name);
-		if (IS_ERR(rescuer->task)) {
-			kfree(rescuer);
-			goto err_destroy;
-		}
-
-		wq->rescuer = rescuer;
-		kthread_bind_mask(rescuer->task, cpu_possible_mask);
-		wake_up_process(rescuer->task);
-	}
+	if (wq_online && init_rescuer(wq) < 0)
+		goto err_destroy;
 
 	if ((wq->flags & WQ_SYSFS) && workqueue_sysfs_register(wq))
 		goto err_destroy;
@@ -4169,6 +4224,22 @@ void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
 EXPORT_SYMBOL_GPL(workqueue_set_max_active);
 
 /**
+ * current_work - retrieve %current task's work struct
+ *
+ * Determine if %current task is a workqueue worker and what it's working on.
+ * Useful to find out the context that the %current task is running in.
+ *
+ * Return: work struct if %current task is a workqueue worker, %NULL otherwise.
+ */
+struct work_struct *current_work(void)
+{
+	struct worker *worker = current_wq_worker();
+
+	return worker ? worker->current_work : NULL;
+}
+EXPORT_SYMBOL(current_work);
+
+/**
  * current_is_workqueue_rescuer - is %current workqueue rescuer?
  *
  * Determine whether %current is a workqueue rescuer.  Can be used from
@@ -5310,7 +5381,7 @@ int workqueue_sysfs_register(struct workqueue_struct *wq)
 
 	ret = device_register(&wq_dev->dev);
 	if (ret) {
-		kfree(wq_dev);
+		put_device(&wq_dev->dev);
 		wq->wq_dev = NULL;
 		return ret;
 	}
@@ -5554,12 +5625,13 @@ static void __init wq_numa_init(void)
 int __init workqueue_init_early(void)
 {
 	int std_nice[NR_STD_WORKER_POOLS] = { 0, HIGHPRI_NICE_LEVEL };
+	int hk_flags = HK_FLAG_DOMAIN | HK_FLAG_WQ;
 	int i, cpu;
 
 	WARN_ON(__alignof__(struct pool_workqueue) < __alignof__(long long));
 
 	BUG_ON(!alloc_cpumask_var(&wq_unbound_cpumask, GFP_KERNEL));
-	cpumask_copy(wq_unbound_cpumask, housekeeping_cpumask(HK_FLAG_DOMAIN));
+	cpumask_copy(wq_unbound_cpumask, housekeeping_cpumask(hk_flags));
 
 	pwq_cache = KMEM_CACHE(pool_workqueue, SLAB_PANIC);
 
@@ -5642,6 +5714,8 @@ int __init workqueue_init(void)
 	 * archs such as power and arm64.  As per-cpu pools created
 	 * previously could be missing node hint and unbound pools NUMA
 	 * affinity, fix them up.
+	 *
+	 * Also, while iterating workqueues, create rescuers if requested.
 	 */
 	wq_numa_init();
 
@@ -5653,8 +5727,12 @@ int __init workqueue_init(void)
 		}
 	}
 
-	list_for_each_entry(wq, &workqueues, list)
+	list_for_each_entry(wq, &workqueues, list) {
 		wq_update_unbound_numa(wq, smp_processor_id(), true);
+		WARN(init_rescuer(wq),
+		     "workqueue: failed to create early rescuer for %s",
+		     wq->name);
+	}
 
 	mutex_unlock(&wq_pool_mutex);