linux-kernel - [PATCH v1] PM: wakeup: Update after recent wakeup source removal ordering change

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Message-ID: <12788103.O9o76ZdvQC@rafael.j.wysocki>
Date: Wed, 12 Nov 2025 17:14:26 +0100
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Linux PM <linux-pm@...r.kernel.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
 Kaushlendra Kumar <kaushlendra.kumar@...el.com>
Subject:
 [PATCH v1] PM: wakeup: Update after recent wakeup source removal ordering
 change

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

After a recent change, wakeup_source_activate() will warn that the given
wakeup source is "unregistered" after its timer has been shut down
in wakeup_source_remove() which may be somewhat confusing, so change
the warning message to say that the wakeup source is "unusable".

Accordingly, rename wakeup_source_not_registered() to
wakeup_source_not_usable() and update the comment in it
to also mention the removal of the wakeup source.

Also restore the comment in wakeup_source_remove() regarding the warning
in wakeup_source_activate() that may trigger after shutting down the
wakeup source timer.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---

This is based on https://lore.kernel.org/linux-pm/20251027044127.2456365-1-kaushlendra.kumar@intel.com/

---
 drivers/base/power/wakeup.c |   16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -189,7 +189,12 @@ static void wakeup_source_remove(struct
 	if (WARN_ON(!ws))
 		return;

+	/*
+	 * After shutting down the timer, wakeup_source_activate() will warn if
+	 * the given wakeup source is passed to it.
+	 */
 	timer_shutdown_sync(&ws->timer);
+
 	raw_spin_lock_irqsave(&events_lock, flags);
 	list_del_rcu(&ws->entry);
 	raw_spin_unlock_irqrestore(&events_lock, flags);
@@ -500,14 +505,14 @@ int device_set_wakeup_enable(struct devi
 EXPORT_SYMBOL_GPL(device_set_wakeup_enable);

 /**
- * wakeup_source_not_registered - validate the given wakeup source.
+ * wakeup_source_not_usable - validate the given wakeup source.
  * @ws: Wakeup source to be validated.
  */
-static bool wakeup_source_not_registered(struct wakeup_source *ws)
+static bool wakeup_source_not_usable(struct wakeup_source *ws)
 {
 	/*
-	 * Use timer struct to check if the given source is initialized
-	 * by wakeup_source_add.
+	 * Use the timer struct to check if the given wakeup source has been
+	 * initialized by wakeup_source_add() and it is not going away.
 	 */
 	return ws->timer.function != pm_wakeup_timer_fn;
 }
@@ -552,8 +557,7 @@ static void wakeup_source_activate(struc
 {
 	unsigned int cec;

-	if (WARN_ONCE(wakeup_source_not_registered(ws),
-			"unregistered wakeup source\n"))
+	if (WARN_ONCE(wakeup_source_not_usable(ws), "unusable wakeup source\n"))
 		return;

 	ws->active = true;