linux-kernel - [PATCH RT 05/22] PM / wakeup: Make events_lock a RAW

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Date:   Wed, 05 Sep 2018 08:27:59 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     linux-kernel@...r.kernel.org,
        linux-rt-users <linux-rt-users@...r.kernel.org>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Carsten Emde <C.Emde@...dl.org>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        John Kacur <jkacur@...hat.com>,
        Paul Gortmaker <paul.gortmaker@...driver.com>,
        Julia Cartwright <julia@...com>,
        Daniel Wagner <daniel.wagner@...mens.com>,
        tom.zanussi@...ux.intel.com
Subject: [PATCH RT 05/22] PM / wakeup: Make events_lock a RAW_SPINLOCK

4.14.63-rt41-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>

[ Upstream commit 1debb85a1d7d5c7655b4574f5b0ddf5f7c84873e ]

The `events_lock' is acquired during suspend while interrupts are
disabled even on RT. The lock is taken only for a very brief moment.
Make it a RAW lock which avoids "sleeping while atomic" warnings on RT.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@...dmis.org>
---
 drivers/base/power/wakeup.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index cdd6f256da59..2269d379c92f 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -52,7 +52,7 @@ static void split_counters(unsigned int *cnt, unsigned int *inpr)
 /* A preserved old value of the events counter. */
 static unsigned int saved_count;
 
-static DEFINE_SPINLOCK(events_lock);
+static DEFINE_RAW_SPINLOCK(events_lock);
 
 static void pm_wakeup_timer_fn(unsigned long data);
 
@@ -180,9 +180,9 @@ void wakeup_source_add(struct wakeup_source *ws)
 	ws->active = false;
 	ws->last_time = ktime_get();
 
-	spin_lock_irqsave(&events_lock, flags);
+	raw_spin_lock_irqsave(&events_lock, flags);
 	list_add_rcu(&ws->entry, &wakeup_sources);
-	spin_unlock_irqrestore(&events_lock, flags);
+	raw_spin_unlock_irqrestore(&events_lock, flags);
 }
 EXPORT_SYMBOL_GPL(wakeup_source_add);
 
@@ -197,9 +197,9 @@ void wakeup_source_remove(struct wakeup_source *ws)
 	if (WARN_ON(!ws))
 		return;
 
-	spin_lock_irqsave(&events_lock, flags);
+	raw_spin_lock_irqsave(&events_lock, flags);
 	list_del_rcu(&ws->entry);
-	spin_unlock_irqrestore(&events_lock, flags);
+	raw_spin_unlock_irqrestore(&events_lock, flags);
 	synchronize_srcu(&wakeup_srcu);
 }
 EXPORT_SYMBOL_GPL(wakeup_source_remove);
@@ -844,7 +844,7 @@ bool pm_wakeup_pending(void)
 	unsigned long flags;
 	bool ret = false;
 
-	spin_lock_irqsave(&events_lock, flags);
+	raw_spin_lock_irqsave(&events_lock, flags);
 	if (events_check_enabled) {
 		unsigned int cnt, inpr;
 
@@ -852,7 +852,7 @@ bool pm_wakeup_pending(void)
 		ret = (cnt != saved_count || inpr > 0);
 		events_check_enabled = !ret;
 	}
-	spin_unlock_irqrestore(&events_lock, flags);
+	raw_spin_unlock_irqrestore(&events_lock, flags);
 
 	if (ret) {
 		pr_info("PM: Wakeup pending, aborting suspend\n");
@@ -941,13 +941,13 @@ bool pm_save_wakeup_count(unsigned int count)
 	unsigned long flags;
 
 	events_check_enabled = false;
-	spin_lock_irqsave(&events_lock, flags);
+	raw_spin_lock_irqsave(&events_lock, flags);
 	split_counters(&cnt, &inpr);
 	if (cnt == count && inpr == 0) {
 		saved_count = count;
 		events_check_enabled = true;
 	}
-	spin_unlock_irqrestore(&events_lock, flags);
+	raw_spin_unlock_irqrestore(&events_lock, flags);
 	return events_check_enabled;
 }
 
-- 
2.18.0