Merge branch 'pm-sleep'

Merge updates related to system suspend and hibernation for
6.20-rc1/7.0-rc1:

 - Stop flagging the PM runtime workqueue as freezable to avoid system
   suspend and resume deadlocks in subsystems that assume asynchronous
   runtime PM to work during system-wide PM transitions (Rafael Wysocki)

 - Drop redundant NULL pointer checks before acomp_request_free() from
   the hibernation code handling image saving (Rafael Wysocki)

 - Update wakeup_sources_walk_start() to handle empty lists of wakeup
   sources as appropriate (Samuel Wu)

 - Make dev_pm_clear_wake_irq() check the power.wakeirq value under
   power.lock to avoid race conditions (Gui-Dong Han)

 - Avoid bit field races related to power.work_in_progress in the core
   device suspend code (Xuewen Yan)

* pm-sleep:
  PM: sleep: core: Avoid bit field races related to work_in_progress
  PM: sleep: wakeirq: harden dev_pm_clear_wake_irq() against races
  PM: wakeup: Handle empty list in wakeup_sources_walk_start()
  PM: hibernate: Drop NULL pointer checks before acomp_request_free()
  PM: sleep: Do not flag runtime PM workqueue as freezable

Author: rafaeljw

Documentation/power/runtime_pm.rst

@@ -712,10 +712,9 @@ out the following operations:
   * During system suspend pm_runtime_get_noresume() is called for every device
     right before executing the subsystem-level .prepare() callback for it and
     pm_runtime_barrier() is called for every device right before executing the
-    subsystem-level .suspend() callback for it.  In addition to that the PM core
-    calls __pm_runtime_disable() with 'false' as the second argument for every
-    device right before executing the subsystem-level .suspend_late() callback
-    for it.
+    subsystem-level .suspend() callback for it.  In addition to that, the PM
+    core disables runtime PM for every device right before executing the
+    subsystem-level .suspend_late() callback for it.
 
   * During system resume pm_runtime_enable() and pm_runtime_put() are called for
     every device right after executing the subsystem-level .resume_early()

drivers/base/power/main.c

@@ -1647,10 +1647,11 @@ static void device_suspend_late(struct device *dev, pm_message_t state, bool asy
 		goto Complete;
 
 	/*
-	 * Disable runtime PM for the device without checking if there is a
-	 * pending resume request for it.
+	 * After this point, any runtime PM operations targeting the device
+	 * will fail until the corresponding pm_runtime_enable() call in
+	 * device_resume_early().
 	 */
-	__pm_runtime_disable(dev, false);
+	pm_runtime_disable(dev);
 
 	if (dev->power.syscore)
 		goto Skip;

drivers/base/power/wakeirq.c

@@ -83,13 +83,16 @@ EXPORT_SYMBOL_GPL(dev_pm_set_wake_irq);
  */
 void dev_pm_clear_wake_irq(struct device *dev)
 {
-	struct wake_irq *wirq = dev->power.wakeirq;
+	struct wake_irq *wirq;
 	unsigned long flags;
 
-	if (!wirq)
+	spin_lock_irqsave(&dev->power.lock, flags);
+	wirq = dev->power.wakeirq;
+	if (!wirq) {
+		spin_unlock_irqrestore(&dev->power.lock, flags);
 		return;
+	}
 
-	spin_lock_irqsave(&dev->power.lock, flags);
 	device_wakeup_detach_irq(dev);
 	dev->power.wakeirq = NULL;
 	spin_unlock_irqrestore(&dev->power.lock, flags);

drivers/base/power/wakeup.c

@@ -275,9 +275,7 @@ EXPORT_SYMBOL_GPL(wakeup_sources_read_unlock);
  */
 struct wakeup_source *wakeup_sources_walk_start(void)
 {
-	struct list_head *ws_head = &wakeup_sources;
-
-	return list_entry_rcu(ws_head->next, struct wakeup_source, entry);
+	return list_first_or_null_rcu(&wakeup_sources, struct wakeup_source, entry);
 }
 EXPORT_SYMBOL_GPL(wakeup_sources_walk_start);
 

include/linux/pm.h

@@ -681,10 +681,10 @@ struct dev_pm_info {
 	struct list_head	entry;
 	struct completion	completion;
 	struct wakeup_source	*wakeup;
+	bool			work_in_progress;	/* Owned by the PM core */
 	bool			wakeup_path:1;
 	bool			syscore:1;
 	bool			no_pm_callbacks:1;	/* Owned by the PM core */
-	bool			work_in_progress:1;	/* Owned by the PM core */
 	bool			smart_suspend:1;	/* Owned by the PM core */
 	bool			must_resume:1;		/* Owned by the PM core */
 	bool			may_skip_resume:1;	/* Set by subsystems */

kernel/power/main.c

@@ -1125,7 +1125,7 @@ EXPORT_SYMBOL_GPL(pm_wq);
 
 static int __init pm_start_workqueues(void)
 {
-	pm_wq = alloc_workqueue("pm", WQ_FREEZABLE | WQ_UNBOUND, 0);
+	pm_wq = alloc_workqueue("pm", WQ_UNBOUND, 0);
 	if (!pm_wq)
 		return -ENOMEM;
 

kernel/power/swap.c

@@ -902,8 +902,8 @@ static int save_compressed_image(struct swap_map_handle *handle,
 		for (thr = 0; thr < nr_threads; thr++) {
 			if (data[thr].thr)
 				kthread_stop(data[thr].thr);
-			if (data[thr].cr)
-				acomp_request_free(data[thr].cr);
+
+			acomp_request_free(data[thr].cr);
 
 			if (!IS_ERR_OR_NULL(data[thr].cc))
 				crypto_free_acomp(data[thr].cc);
@@ -1502,8 +1502,8 @@ static int load_compressed_image(struct swap_map_handle *handle,
 		for (thr = 0; thr < nr_threads; thr++) {
 			if (data[thr].thr)
 				kthread_stop(data[thr].thr);
-			if (data[thr].cr)
-				acomp_request_free(data[thr].cr);
+
+			acomp_request_free(data[thr].cr);
 
 			if (!IS_ERR_OR_NULL(data[thr].cc))
 				crypto_free_acomp(data[thr].cc);