Merge branch 'reset/of-get-optional-exclusive' of git://git.pengutronix.de/pza/linux into timers/drivers/next

"Add optional variant of of_reset_control_get_exclusive(). If the
requested reset is not specified in the device tree, this function
returns NULL instead of an error."

This dependency is needed for the Generic Timer Module (a.k.a OSTM)
support for RZ/G2L.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

1 files changed, 215 insertions, 142 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index f148eacda55a..613917bbc4e7 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -205,9 +205,26 @@ struct pool_workqueue {
 	int			refcnt;		/* L: reference count */
 	int			nr_in_flight[WORK_NR_COLORS];
 						/* L: nr of in_flight works */
+
+	/*
+	 * nr_active management and WORK_STRUCT_INACTIVE:
+	 *
+	 * When pwq->nr_active >= max_active, new work item is queued to
+	 * pwq->inactive_works instead of pool->worklist and marked with
+	 * WORK_STRUCT_INACTIVE.
+	 *
+	 * All work items marked with WORK_STRUCT_INACTIVE do not participate
+	 * in pwq->nr_active and all work items in pwq->inactive_works are
+	 * marked with WORK_STRUCT_INACTIVE.  But not all WORK_STRUCT_INACTIVE
+	 * work items are in pwq->inactive_works.  Some of them are ready to
+	 * run in pool->worklist or worker->scheduled.  Those work itmes are
+	 * only struct wq_barrier which is used for flush_work() and should
+	 * not participate in pwq->nr_active.  For non-barrier work item, it
+	 * is marked with WORK_STRUCT_INACTIVE iff it is in pwq->inactive_works.
+	 */
 	int			nr_active;	/* L: nr of active works */
 	int			max_active;	/* L: max active works */
-	struct list_head	delayed_works;	/* L: delayed works */
+	struct list_head	inactive_works;	/* L: inactive works */
 	struct list_head	pwqs_node;	/* WR: node on wq->pwqs */
 	struct list_head	mayday_node;	/* MD: node on wq->maydays */
 
@@ -358,6 +375,7 @@ EXPORT_SYMBOL_GPL(system_freezable_power_efficient_wq);
 static int worker_thread(void *__worker);
 static void workqueue_sysfs_unregister(struct workqueue_struct *wq);
 static void show_pwq(struct pool_workqueue *pwq);
+static void show_one_worker_pool(struct worker_pool *pool);
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/workqueue.h>
@@ -524,7 +542,7 @@ static inline void debug_work_deactivate(struct work_struct *work) { }
 #endif
 
 /**
- * worker_pool_assign_id - allocate ID and assing it to @pool
+ * worker_pool_assign_id - allocate ID and assign it to @pool
  * @pool: the pool pointer of interest
  *
  * Returns 0 if ID in [0, WORK_OFFQ_POOL_NONE) is allocated and assigned
@@ -579,9 +597,9 @@ static unsigned int work_color_to_flags(int color)
 	return color << WORK_STRUCT_COLOR_SHIFT;
 }
 
-static int get_work_color(struct work_struct *work)
+static int get_work_color(unsigned long work_data)
 {
-	return (*work_data_bits(work) >> WORK_STRUCT_COLOR_SHIFT) &
+	return (work_data >> WORK_STRUCT_COLOR_SHIFT) &
 		((1 << WORK_STRUCT_COLOR_BITS) - 1);
 }
 
@@ -1136,7 +1154,7 @@ static void put_pwq_unlocked(struct pool_workqueue *pwq)
 	}
 }
 
-static void pwq_activate_delayed_work(struct work_struct *work)
+static void pwq_activate_inactive_work(struct work_struct *work)
 {
 	struct pool_workqueue *pwq = get_work_pwq(work);
 
@@ -1144,22 +1162,22 @@ static void pwq_activate_delayed_work(struct work_struct *work)
 	if (list_empty(&pwq->pool->worklist))
 		pwq->pool->watchdog_ts = jiffies;
 	move_linked_works(work, &pwq->pool->worklist, NULL);
-	__clear_bit(WORK_STRUCT_DELAYED_BIT, work_data_bits(work));
+	__clear_bit(WORK_STRUCT_INACTIVE_BIT, work_data_bits(work));
 	pwq->nr_active++;
 }
 
-static void pwq_activate_first_delayed(struct pool_workqueue *pwq)
+static void pwq_activate_first_inactive(struct pool_workqueue *pwq)
 {
-	struct work_struct *work = list_first_entry(&pwq->delayed_works,
+	struct work_struct *work = list_first_entry(&pwq->inactive_works,
 						    struct work_struct, entry);
 
-	pwq_activate_delayed_work(work);
+	pwq_activate_inactive_work(work);
 }
 
 /**
  * pwq_dec_nr_in_flight - decrement pwq's nr_in_flight
  * @pwq: pwq of interest
- * @color: color of work which left the queue
+ * @work_data: work_data of work which left the queue
  *
  * A work either has completed or is removed from pending queue,
  * decrement nr_in_flight of its pwq and handle workqueue flushing.
@@ -1167,21 +1185,21 @@ static void pwq_activate_first_delayed(struct pool_workqueue *pwq)
  * CONTEXT:
  * raw_spin_lock_irq(pool->lock).
  */
-static void pwq_dec_nr_in_flight(struct pool_workqueue *pwq, int color)
+static void pwq_dec_nr_in_flight(struct pool_workqueue *pwq, unsigned long work_data)
 {
-	/* uncolored work items don't participate in flushing or nr_active */
-	if (color == WORK_NO_COLOR)
-		goto out_put;
+	int color = get_work_color(work_data);
 
-	pwq->nr_in_flight[color]--;
-
-	pwq->nr_active--;
-	if (!list_empty(&pwq->delayed_works)) {
-		/* one down, submit a delayed one */
-		if (pwq->nr_active < pwq->max_active)
-			pwq_activate_first_delayed(pwq);
+	if (!(work_data & WORK_STRUCT_INACTIVE)) {
+		pwq->nr_active--;
+		if (!list_empty(&pwq->inactive_works)) {
+			/* one down, submit an inactive one */
+			if (pwq->nr_active < pwq->max_active)
+				pwq_activate_first_inactive(pwq);
+		}
 	}
 
+	pwq->nr_in_flight[color]--;
+
 	/* is flush in progress and are we at the flushing tip? */
 	if (likely(pwq->flush_color != color))
 		goto out_put;
@@ -1281,17 +1299,21 @@ static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
 		debug_work_deactivate(work);
 
 		/*
-		 * A delayed work item cannot be grabbed directly because
-		 * it might have linked NO_COLOR work items which, if left
-		 * on the delayed_list, will confuse pwq->nr_active
+		 * A cancelable inactive work item must be in the
+		 * pwq->inactive_works since a queued barrier can't be
+		 * canceled (see the comments in insert_wq_barrier()).
+		 *
+		 * An inactive work item cannot be grabbed directly because
+		 * it might have linked barrier work items which, if left
+		 * on the inactive_works list, will confuse pwq->nr_active
 		 * management later on and cause stall.  Make sure the work
 		 * item is activated before grabbing.
 		 */
-		if (*work_data_bits(work) & WORK_STRUCT_DELAYED)
-			pwq_activate_delayed_work(work);
+		if (*work_data_bits(work) & WORK_STRUCT_INACTIVE)
+			pwq_activate_inactive_work(work);
 
 		list_del_init(&work->entry);
-		pwq_dec_nr_in_flight(pwq, get_work_color(work));
+		pwq_dec_nr_in_flight(pwq, *work_data_bits(work));
 
 		/* work->data points to pwq iff queued, point to pool */
 		set_work_pool_and_keep_pending(work, pool->id);
@@ -1329,7 +1351,7 @@ static void insert_work(struct pool_workqueue *pwq, struct work_struct *work,
 	struct worker_pool *pool = pwq->pool;
 
 	/* record the work call stack in order to print it in KASAN reports */
-	kasan_record_aux_stack(work);
+	kasan_record_aux_stack_noalloc(work);
 
 	/* we own @work, set data and link */
 	set_work_pwq(work, pwq, extra_flags);
@@ -1490,8 +1512,8 @@ retry:
 		if (list_empty(worklist))
 			pwq->pool->watchdog_ts = jiffies;
 	} else {
-		work_flags |= WORK_STRUCT_DELAYED;
-		worklist = &pwq->delayed_works;
+		work_flags |= WORK_STRUCT_INACTIVE;
+		worklist = &pwq->inactive_works;
 	}
 
 	debug_work_activate(work);
@@ -1912,14 +1934,14 @@ static void worker_detach_from_pool(struct worker *worker)
  */
 static struct worker *create_worker(struct worker_pool *pool)
 {
-	struct worker *worker = NULL;
-	int id = -1;
+	struct worker *worker;
+	int id;
 	char id_buf[16];
 
 	/* ID is needed to determine kthread name */
-	id = ida_simple_get(&pool->worker_ida, 0, 0, GFP_KERNEL);
+	id = ida_alloc(&pool->worker_ida, GFP_KERNEL);
 	if (id < 0)
-		goto fail;
+		return NULL;
 
 	worker = alloc_worker(pool->node);
 	if (!worker)
@@ -1954,8 +1976,7 @@ static struct worker *create_worker(struct worker_pool *pool)
 	return worker;
 
 fail:
-	if (id >= 0)
-		ida_simple_remove(&pool->worker_ida, id);
+	ida_free(&pool->worker_ida, id);
 	kfree(worker);
 	return NULL;
 }
@@ -2173,7 +2194,7 @@ __acquires(&pool->lock)
 	struct pool_workqueue *pwq = get_work_pwq(work);
 	struct worker_pool *pool = worker->pool;
 	bool cpu_intensive = pwq->wq->flags & WQ_CPU_INTENSIVE;
-	int work_color;
+	unsigned long work_data;
 	struct worker *collision;
 #ifdef CONFIG_LOCKDEP
 	/*
@@ -2209,7 +2230,8 @@ __acquires(&pool->lock)
 	worker->current_work = work;
 	worker->current_func = work->func;
 	worker->current_pwq = pwq;
-	work_color = get_work_color(work);
+	work_data = *work_data_bits(work);
+	worker->current_color = get_work_color(work_data);
 
 	/*
 	 * Record wq name for cmdline and debug reporting, may get
@@ -2315,7 +2337,8 @@ __acquires(&pool->lock)
 	worker->current_work = NULL;
 	worker->current_func = NULL;
 	worker->current_pwq = NULL;
-	pwq_dec_nr_in_flight(pwq, work_color);
+	worker->current_color = INT_MAX;
+	pwq_dec_nr_in_flight(pwq, work_data);
 }
 
 /**
@@ -2378,7 +2401,7 @@ woke_up:
 		set_pf_worker(false);
 
 		set_task_comm(worker->task, "kworker/dying");
-		ida_simple_remove(&pool->worker_ida, worker->id);
+		ida_free(&pool->worker_ida, worker->id);
 		worker_detach_from_pool(worker);
 		kfree(worker);
 		return 0;
@@ -2531,7 +2554,7 @@ repeat:
 			/*
 			 * The above execution of rescued work items could
 			 * have created more to rescue through
-			 * pwq_activate_first_delayed() or chained
+			 * pwq_activate_first_inactive() or chained
 			 * queueing.  Let's put @pwq back on mayday list so
 			 * that such back-to-back work items, which may be
 			 * being used to relieve memory pressure, don't
@@ -2658,8 +2681,9 @@ static void insert_wq_barrier(struct pool_workqueue *pwq,
 			      struct wq_barrier *barr,
 			      struct work_struct *target, struct worker *worker)
 {
+	unsigned int work_flags = 0;
+	unsigned int work_color;
 	struct list_head *head;
-	unsigned int linked = 0;
 
 	/*
 	 * debugobject calls are safe here even with pool->lock locked
@@ -2674,24 +2698,31 @@ static void insert_wq_barrier(struct pool_workqueue *pwq,
 
 	barr->task = current;
 
+	/* The barrier work item does not participate in pwq->nr_active. */
+	work_flags |= WORK_STRUCT_INACTIVE;
+
 	/*
 	 * If @target is currently being executed, schedule the
 	 * barrier to the worker; otherwise, put it after @target.
 	 */
-	if (worker)
+	if (worker) {
 		head = worker->scheduled.next;
-	else {
+		work_color = worker->current_color;
+	} else {
 		unsigned long *bits = work_data_bits(target);
 
 		head = target->entry.next;
 		/* there can already be other linked works, inherit and set */
-		linked = *bits & WORK_STRUCT_LINKED;
+		work_flags |= *bits & WORK_STRUCT_LINKED;
+		work_color = get_work_color(*bits);
 		__set_bit(WORK_STRUCT_LINKED_BIT, bits);
 	}
 
+	pwq->nr_in_flight[work_color]++;
+	work_flags |= work_color_to_flags(work_color);
+
 	debug_work_activate(&barr->work);
-	insert_work(pwq, &barr->work, head,
-		    work_color_to_flags(WORK_NO_COLOR) | linked);
+	insert_work(pwq, &barr->work, head, work_flags);
 }
 
 /**
@@ -2957,7 +2988,7 @@ reflush:
 		bool drained;
 
 		raw_spin_lock_irq(&pwq->pool->lock);
-		drained = !pwq->nr_active && list_empty(&pwq->delayed_works);
+		drained = !pwq->nr_active && list_empty(&pwq->inactive_works);
 		raw_spin_unlock_irq(&pwq->pool->lock);
 
 		if (drained)
@@ -3293,7 +3324,7 @@ int schedule_on_each_cpu(work_func_t func)
 	if (!works)
 		return -ENOMEM;
 
-	get_online_cpus();
+	cpus_read_lock();
 
 	for_each_online_cpu(cpu) {
 		struct work_struct *work = per_cpu_ptr(works, cpu);
@@ -3305,7 +3336,7 @@ int schedule_on_each_cpu(work_func_t func)
 	for_each_online_cpu(cpu)
 		flush_work(per_cpu_ptr(works, cpu));
 
-	put_online_cpus();
+	cpus_read_unlock();
 	free_percpu(works);
 	return 0;
 }
@@ -3713,7 +3744,7 @@ static void pwq_unbound_release_workfn(struct work_struct *work)
  * @pwq: target pool_workqueue
  *
  * If @pwq isn't freezing, set @pwq->max_active to the associated
- * workqueue's saved_max_active and activate delayed work items
+ * workqueue's saved_max_active and activate inactive work items
  * accordingly.  If @pwq is freezing, clear @pwq->max_active to zero.
  */
 static void pwq_adjust_max_active(struct pool_workqueue *pwq)
@@ -3742,9 +3773,9 @@ static void pwq_adjust_max_active(struct pool_workqueue *pwq)
 
 		pwq->max_active = wq->saved_max_active;
 
-		while (!list_empty(&pwq->delayed_works) &&
+		while (!list_empty(&pwq->inactive_works) &&
 		       pwq->nr_active < pwq->max_active) {
-			pwq_activate_first_delayed(pwq);
+			pwq_activate_first_inactive(pwq);
 			kick = true;
 		}
 
@@ -3763,7 +3794,7 @@ static void pwq_adjust_max_active(struct pool_workqueue *pwq)
 	raw_spin_unlock_irqrestore(&pwq->pool->lock, flags);
 }
 
-/* initialize newly alloced @pwq which is associated with @wq and @pool */
+/* initialize newly allocated @pwq which is associated with @wq and @pool */
 static void init_pwq(struct pool_workqueue *pwq, struct workqueue_struct *wq,
 		     struct worker_pool *pool)
 {
@@ -3775,7 +3806,7 @@ static void init_pwq(struct pool_workqueue *pwq, struct workqueue_struct *wq,
 	pwq->wq = wq;
 	pwq->flush_color = -1;
 	pwq->refcnt = 1;
-	INIT_LIST_HEAD(&pwq->delayed_works);
+	INIT_LIST_HEAD(&pwq->inactive_works);
 	INIT_LIST_HEAD(&pwq->pwqs_node);
 	INIT_LIST_HEAD(&pwq->mayday_node);
 	INIT_WORK(&pwq->unbound_release_work, pwq_unbound_release_workfn);
@@ -4016,14 +4047,14 @@ static void apply_wqattrs_commit(struct apply_wqattrs_ctx *ctx)
 static void apply_wqattrs_lock(void)
 {
 	/* CPUs should stay stable across pwq creations and installations */
-	get_online_cpus();
+	cpus_read_lock();
 	mutex_lock(&wq_pool_mutex);
 }
 
 static void apply_wqattrs_unlock(void)
 {
 	mutex_unlock(&wq_pool_mutex);
-	put_online_cpus();
+	cpus_read_unlock();
 }
 
 static int apply_workqueue_attrs_locked(struct workqueue_struct *wq,
@@ -4068,7 +4099,7 @@ static int apply_workqueue_attrs_locked(struct workqueue_struct *wq,
  *
  * Performs GFP_KERNEL allocations.
  *
- * Assumes caller has CPU hotplug read exclusion, i.e. get_online_cpus().
+ * Assumes caller has CPU hotplug read exclusion, i.e. cpus_read_lock().
  *
  * Return: 0 on success and -errno on failure.
  */
@@ -4196,7 +4227,7 @@ static int alloc_and_link_pwqs(struct workqueue_struct *wq)
 		return 0;
 	}
 
-	get_online_cpus();
+	cpus_read_lock();
 	if (wq->flags & __WQ_ORDERED) {
 		ret = apply_workqueue_attrs(wq, ordered_wq_attrs[highpri]);
 		/* there should only be single pwq for ordering guarantee */
@@ -4206,7 +4237,7 @@ static int alloc_and_link_pwqs(struct workqueue_struct *wq)
 	} else {
 		ret = apply_workqueue_attrs(wq, unbound_std_wq_attrs[highpri]);
 	}
-	put_online_cpus();
+	cpus_read_unlock();
 
 	return ret;
 }
@@ -4362,7 +4393,7 @@ static bool pwq_busy(struct pool_workqueue *pwq)
 
 	if ((pwq != pwq->wq->dfl_pwq) && (pwq->refcnt > 1))
 		return true;
-	if (pwq->nr_active || !list_empty(&pwq->delayed_works))
+	if (pwq->nr_active || !list_empty(&pwq->inactive_works))
 		return true;
 
 	return false;
@@ -4417,7 +4448,7 @@ void destroy_workqueue(struct workqueue_struct *wq)
 			raw_spin_unlock_irq(&pwq->pool->lock);
 			mutex_unlock(&wq->mutex);
 			mutex_unlock(&wq_pool_mutex);
-			show_workqueue_state();
+			show_one_workqueue(wq);
 			return;
 		}
 		raw_spin_unlock_irq(&pwq->pool->lock);
@@ -4558,7 +4589,7 @@ bool workqueue_congested(int cpu, struct workqueue_struct *wq)
 	else
 		pwq = unbound_pwq_by_node(wq, cpu_to_node(cpu));
 
-	ret = !list_empty(&pwq->delayed_works);
+	ret = !list_empty(&pwq->inactive_works);
 	preempt_enable();
 	rcu_read_unlock();
 
@@ -4754,11 +4785,11 @@ static void show_pwq(struct pool_workqueue *pwq)
 		pr_cont("\n");
 	}
 
-	if (!list_empty(&pwq->delayed_works)) {
+	if (!list_empty(&pwq->inactive_works)) {
 		bool comma = false;
 
-		pr_info("    delayed:");
-		list_for_each_entry(work, &pwq->delayed_works, entry) {
+		pr_info("    inactive:");
+		list_for_each_entry(work, &pwq->inactive_works, entry) {
 			pr_cont_work(comma, work);
 			comma = !(*work_data_bits(work) & WORK_STRUCT_LINKED);
 		}
@@ -4767,83 +4798,116 @@ static void show_pwq(struct pool_workqueue *pwq)
 }
 
 /**
- * show_workqueue_state - dump workqueue state
- *
- * Called from a sysrq handler or try_to_freeze_tasks() and prints out
- * all busy workqueues and pools.
+ * show_one_workqueue - dump state of specified workqueue
+ * @wq: workqueue whose state will be printed
  */
-void show_workqueue_state(void)
+void show_one_workqueue(struct workqueue_struct *wq)
 {
-	struct workqueue_struct *wq;
-	struct worker_pool *pool;
+	struct pool_workqueue *pwq;
+	bool idle = true;
 	unsigned long flags;
-	int pi;
-
-	rcu_read_lock();
 
-	pr_info("Showing busy workqueues and worker pools:\n");
-
-	list_for_each_entry_rcu(wq, &workqueues, list) {
-		struct pool_workqueue *pwq;
-		bool idle = true;
-
-		for_each_pwq(pwq, wq) {
-			if (pwq->nr_active || !list_empty(&pwq->delayed_works)) {
-				idle = false;
-				break;
-			}
+	for_each_pwq(pwq, wq) {
+		if (pwq->nr_active || !list_empty(&pwq->inactive_works)) {
+			idle = false;
+			break;
 		}
-		if (idle)
-			continue;
+	}
+	if (idle) /* Nothing to print for idle workqueue */
+		return;
 
-		pr_info("workqueue %s: flags=0x%x\n", wq->name, wq->flags);
+	pr_info("workqueue %s: flags=0x%x\n", wq->name, wq->flags);
 
-		for_each_pwq(pwq, wq) {
-			raw_spin_lock_irqsave(&pwq->pool->lock, flags);
-			if (pwq->nr_active || !list_empty(&pwq->delayed_works))
-				show_pwq(pwq);
-			raw_spin_unlock_irqrestore(&pwq->pool->lock, flags);
+	for_each_pwq(pwq, wq) {
+		raw_spin_lock_irqsave(&pwq->pool->lock, flags);
+		if (pwq->nr_active || !list_empty(&pwq->inactive_works)) {
 			/*
-			 * We could be printing a lot from atomic context, e.g.
-			 * sysrq-t -> show_workqueue_state(). Avoid triggering
-			 * hard lockup.
+			 * Defer printing to avoid deadlocks in console
+			 * drivers that queue work while holding locks
+			 * also taken in their write paths.
 			 */
-			touch_nmi_watchdog();
-		}
-	}
-
-	for_each_pool(pool, pi) {
-		struct worker *worker;
-		bool first = true;
-
-		raw_spin_lock_irqsave(&pool->lock, flags);
-		if (pool->nr_workers == pool->nr_idle)
-			goto next_pool;
-
-		pr_info("pool %d:", pool->id);
-		pr_cont_pool_info(pool);
-		pr_cont(" hung=%us workers=%d",
-			jiffies_to_msecs(jiffies - pool->watchdog_ts) / 1000,
-			pool->nr_workers);
-		if (pool->manager)
-			pr_cont(" manager: %d",
-				task_pid_nr(pool->manager->task));
-		list_for_each_entry(worker, &pool->idle_list, entry) {
-			pr_cont(" %s%d", first ? "idle: " : "",
-				task_pid_nr(worker->task));
-			first = false;
+			printk_deferred_enter();
+			show_pwq(pwq);
+			printk_deferred_exit();
 		}
-		pr_cont("\n");
-	next_pool:
-		raw_spin_unlock_irqrestore(&pool->lock, flags);
+		raw_spin_unlock_irqrestore(&pwq->pool->lock, flags);
 		/*
 		 * We could be printing a lot from atomic context, e.g.
-		 * sysrq-t -> show_workqueue_state(). Avoid triggering
+		 * sysrq-t -> show_all_workqueues(). Avoid triggering
 		 * hard lockup.
 		 */
 		touch_nmi_watchdog();
 	}
 
+}
+
+/**
+ * show_one_worker_pool - dump state of specified worker pool
+ * @pool: worker pool whose state will be printed
+ */
+static void show_one_worker_pool(struct worker_pool *pool)
+{
+	struct worker *worker;
+	bool first = true;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&pool->lock, flags);
+	if (pool->nr_workers == pool->nr_idle)
+		goto next_pool;
+	/*
+	 * Defer printing to avoid deadlocks in console drivers that
+	 * queue work while holding locks also taken in their write
+	 * paths.
+	 */
+	printk_deferred_enter();
+	pr_info("pool %d:", pool->id);
+	pr_cont_pool_info(pool);
+	pr_cont(" hung=%us workers=%d",
+		jiffies_to_msecs(jiffies - pool->watchdog_ts) / 1000,
+		pool->nr_workers);
+	if (pool->manager)
+		pr_cont(" manager: %d",
+			task_pid_nr(pool->manager->task));
+	list_for_each_entry(worker, &pool->idle_list, entry) {
+		pr_cont(" %s%d", first ? "idle: " : "",
+			task_pid_nr(worker->task));
+		first = false;
+	}
+	pr_cont("\n");
+	printk_deferred_exit();
+next_pool:
+	raw_spin_unlock_irqrestore(&pool->lock, flags);
+	/*
+	 * We could be printing a lot from atomic context, e.g.
+	 * sysrq-t -> show_all_workqueues(). Avoid triggering
+	 * hard lockup.
+	 */
+	touch_nmi_watchdog();
+
+}
+
+/**
+ * show_all_workqueues - dump workqueue state
+ *
+ * Called from a sysrq handler or try_to_freeze_tasks() and prints out
+ * all busy workqueues and pools.
+ */
+void show_all_workqueues(void)
+{
+	struct workqueue_struct *wq;
+	struct worker_pool *pool;
+	int pi;
+
+	rcu_read_lock();
+
+	pr_info("Showing busy workqueues and worker pools:\n");
+
+	list_for_each_entry_rcu(wq, &workqueues, list)
+		show_one_workqueue(wq);
+
+	for_each_pool(pool, pi)
+		show_one_worker_pool(pool);
+
 	rcu_read_unlock();
 }
 
@@ -5168,10 +5232,10 @@ long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg)
 {
 	long ret = -ENODEV;
 
-	get_online_cpus();
+	cpus_read_lock();
 	if (cpu_online(cpu))
 		ret = work_on_cpu(cpu, fn, arg);
-	put_online_cpus();
+	cpus_read_unlock();
 	return ret;
 }
 EXPORT_SYMBOL_GPL(work_on_cpu_safe);
@@ -5183,7 +5247,7 @@ EXPORT_SYMBOL_GPL(work_on_cpu_safe);
  * freeze_workqueues_begin - begin freezing workqueues
  *
  * Start freezing workqueues.  After this function returns, all freezable
- * workqueues will queue new works to their delayed_works list instead of
+ * workqueues will queue new works to their inactive_works list instead of
  * pool->worklist.
  *
  * CONTEXT:
@@ -5331,7 +5395,7 @@ static int workqueue_apply_unbound_cpumask(void)
  *  the affinity of all unbound workqueues.  This function check the @cpumask
  *  and apply it to all unbound workqueues and updates all pwqs of them.
  *
- *  Retun:	0	- Success
+ *  Return:	0	- Success
  *  		-EINVAL	- Invalid @cpumask
  *  		-ENOMEM	- Failed to allocate memory for attrs or pwqs.
  */
@@ -5340,9 +5404,6 @@ int workqueue_set_unbound_cpumask(cpumask_var_t cpumask)
 	int ret = -EINVAL;
 	cpumask_var_t saved_cpumask;
 
-	if (!zalloc_cpumask_var(&saved_cpumask, GFP_KERNEL))
-		return -ENOMEM;
-
 	/*
 	 * Not excluding isolated cpus on purpose.
 	 * If the user wishes to include them, we allow that.
@@ -5350,6 +5411,15 @@ int workqueue_set_unbound_cpumask(cpumask_var_t cpumask)
 	cpumask_and(cpumask, cpumask, cpu_possible_mask);
 	if (!cpumask_empty(cpumask)) {
 		apply_wqattrs_lock();
+		if (cpumask_equal(cpumask, wq_unbound_cpumask)) {
+			ret = 0;
+			goto out_unlock;
+		}
+
+		if (!zalloc_cpumask_var(&saved_cpumask, GFP_KERNEL)) {
+			ret = -ENOMEM;
+			goto out_unlock;
+		}
 
 		/* save the old wq_unbound_cpumask. */
 		cpumask_copy(saved_cpumask, wq_unbound_cpumask);
@@ -5362,10 +5432,11 @@ int workqueue_set_unbound_cpumask(cpumask_var_t cpumask)
 		if (ret < 0)
 			cpumask_copy(wq_unbound_cpumask, saved_cpumask);
 
+		free_cpumask_var(saved_cpumask);
+out_unlock:
 		apply_wqattrs_unlock();
 	}
 
-	free_cpumask_var(saved_cpumask);
 	return ret;
 }
 
@@ -5443,7 +5514,7 @@ static ssize_t wq_pool_ids_show(struct device *dev,
 	const char *delim = "";
 	int node, written = 0;
 
-	get_online_cpus();
+	cpus_read_lock();
 	rcu_read_lock();
 	for_each_node(node) {
 		written += scnprintf(buf + written, PAGE_SIZE - written,
@@ -5453,7 +5524,7 @@ static ssize_t wq_pool_ids_show(struct device *dev,
 	}
 	written += scnprintf(buf + written, PAGE_SIZE - written, "\n");
 	rcu_read_unlock();
-	put_online_cpus();
+	cpus_read_unlock();
 
 	return written;
 }
@@ -5825,7 +5896,7 @@ static void wq_watchdog_timer_fn(struct timer_list *unused)
 	rcu_read_unlock();
 
 	if (lockup_detected)
-		show_workqueue_state();
+		show_all_workqueues();
 
 	wq_watchdog_reset_touched();
 	mod_timer(&wq_watchdog_timer, jiffies + thresh);
@@ -5902,6 +5973,13 @@ static void __init wq_numa_init(void)
 		return;
 	}
 
+	for_each_possible_cpu(cpu) {
+		if (WARN_ON(cpu_to_node(cpu) == NUMA_NO_NODE)) {
+			pr_warn("workqueue: NUMA node mapping not available for cpu%d, disabling NUMA support\n", cpu);
+			return;
+		}
+	}
+
 	wq_update_unbound_numa_attrs_buf = alloc_workqueue_attrs();
 	BUG_ON(!wq_update_unbound_numa_attrs_buf);
 
@@ -5919,11 +5997,6 @@ static void __init wq_numa_init(void)
 
 	for_each_possible_cpu(cpu) {
 		node = cpu_to_node(cpu);
-		if (WARN_ON(node == NUMA_NO_NODE)) {
-			pr_warn("workqueue: NUMA node mapping not available for cpu%d, disabling NUMA support\n", cpu);
-			/* happens iff arch is bonkers, let's just proceed */
-			return;
-		}
 		cpumask_set_cpu(cpu, tbl[node]);
 	}