1 files changed, 45 insertions, 9 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index bfeef512f6dd..1ae3732a2c51 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -3197,7 +3197,16 @@ restart:
 #ifdef CONFIG_PREEMPT_RT
 static void worker_lock_callback(struct worker_pool *pool)
 {
-	spin_lock(&pool->cb_lock);
+	/*
+	 * SINGLE_DEPTH_NESTING is for a dead pool's bh_worker() running from
+	 * drain_dead_softirq_workfn() inside a live pool's bh_worker(). The
+	 * unlocked read is stable: the flag is only set while @pool's CPU is
+	 * dead, inside a serialized hotplug operation. data_race() as the value
+	 * only affects the lockdep annotation and the read can be elided when
+	 * lockdep is disabled.
+	 */
+	spin_lock_nested(&pool->cb_lock,
+			 data_race(pool->flags) & POOL_BH_DRAINING ? SINGLE_DEPTH_NESTING : 0);
 }
 
 static void worker_unlock_callback(struct worker_pool *pool)
@@ -5285,12 +5294,6 @@ static void pwq_release_workfn(struct kthread_work *work)
 		mutex_unlock(&wq->mutex);
 	}
 
-	if (!is_percpu_pool(pool)) {
-		mutex_lock(&wq_pool_mutex);
-		put_unbound_pool(pool);
-		mutex_unlock(&wq_pool_mutex);
-	}
-
 	if (!list_empty(&pwq->pending_node)) {
 		struct wq_node_nr_active *nna =
 			wq_node_nr_active(pwq->wq, pwq->pool->node);
@@ -5300,6 +5303,12 @@ static void pwq_release_workfn(struct kthread_work *work)
 		raw_spin_unlock_irq(&nna->lock);
 	}
 
+	if (!is_percpu_pool(pool)) {
+		mutex_lock(&wq_pool_mutex);
+		put_unbound_pool(pool);
+		mutex_unlock(&wq_pool_mutex);
+	}
+
 	kfree_rcu(pwq, rcu);
 
 	/*
@@ -6294,6 +6303,30 @@ bool current_is_workqueue_rescuer(void)
 }
 
 /**
+ * current_is_workqueue_mem_reclaim - is %current a %WQ_MEM_RECLAIM worker?
+ *
+ * Determine whether %current is a workqueue worker executing on a workqueue
+ * created with %WQ_MEM_RECLAIM.  This mirrors the condition that
+ * check_flush_dependency() warns on: flushing (or otherwise waiting on) a
+ * !WQ_MEM_RECLAIM workqueue from such a context breaks the forward-progress
+ * guarantee and can deadlock.  Callers that may recurse into such a flush --
+ * e.g. NFS LOCALIO submitting into a stacked filesystem that flushes its own
+ * !WQ_MEM_RECLAIM workqueue -- can use this to decide whether they must defer
+ * the work to a !WQ_MEM_RECLAIM workqueue rather than run it inline.
+ *
+ * Return: %true if %current is a %WQ_MEM_RECLAIM worker.  %false otherwise.
+ */
+bool current_is_workqueue_mem_reclaim(void)
+{
+	struct worker *worker = current_wq_worker();
+
+	return worker &&
+		((worker->current_pwq->wq->flags &
+		  (WQ_MEM_RECLAIM | __WQ_LEGACY)) == WQ_MEM_RECLAIM);
+}
+EXPORT_SYMBOL_GPL(current_is_workqueue_mem_reclaim);
+
+/**
  * workqueue_congested - test whether a workqueue is congested
  * @cpu: CPU in question
  * @wq: target workqueue
@@ -8026,6 +8059,9 @@ static int wq_watchdog_param_set_thresh(const char *val,
 	if (ret)
 		return ret;
 
+	if (thresh > MAX_JIFFY_OFFSET / HZ)
+		return -ERANGE;
+
 	if (system_percpu_wq)
 		wq_watchdog_set_thresh(thresh);
 	else
@@ -8056,12 +8092,12 @@ static inline void wq_watchdog_init(void) { }
 
 static void bh_pool_kick_normal(struct irq_work *irq_work)
 {
-	raise_softirq_irqoff(TASKLET_SOFTIRQ);
+	raise_softirq(TASKLET_SOFTIRQ);
 }
 
 static void bh_pool_kick_highpri(struct irq_work *irq_work)
 {
-	raise_softirq_irqoff(HI_SOFTIRQ);
+	raise_softirq(HI_SOFTIRQ);
 }
 
 static void __init restrict_unbound_cpumask(const char *name, const struct cpumask *mask)