linux-kernel - [patch V2 03/10] hrtimer: Ensure timerfd notification for HIGHRES=n

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Message-Id: <20210713135158.196661266@linutronix.de>
Date:   Tue, 13 Jul 2021 15:39:48 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Anna-Maria Behnsen <anna-maria@...utronix.de>,
        Marcelo Tosatti <mtosatti@...hat.com>,
        Frederic Weisbecker <frederic@...nel.org>
Subject: [patch V2 03/10] hrtimer: Ensure timerfd notification for HIGHRES=n

From: Thomas Gleixner <tglx@...utronix.de>

If high resolution timers are disabled the timerfd notification about a
clock was set event is not happening for all cases which use
clock_was_set_delayed() because that's a NOP for HIGHRES=n, which is wrong.

Make clock_was_set_delayed() unconditially available to fix that.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 include/linux/hrtimer.h     |    5 -----
 kernel/time/hrtimer.c       |   32 ++++++++++++++++----------------
 kernel/time/tick-internal.h |    3 +++
 3 files changed, 19 insertions(+), 21 deletions(-)

--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -318,16 +318,12 @@ struct clock_event_device;
 
 extern void hrtimer_interrupt(struct clock_event_device *dev);
 
-extern void clock_was_set_delayed(void);
-
 extern unsigned int hrtimer_resolution;
 
 #else
 
 #define hrtimer_resolution	(unsigned int)LOW_RES_NSEC
 
-static inline void clock_was_set_delayed(void) { }
-
 #endif
 
 static inline ktime_t
@@ -351,7 +347,6 @@ hrtimer_expires_remaining_adjusted(const
 						    timer->base->get_time());
 }
 
-extern void clock_was_set(void);
 #ifdef CONFIG_TIMERFD
 extern void timerfd_clock_was_set(void);
 #else
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -777,22 +777,6 @@ static void hrtimer_switch_to_hres(void)
 	retrigger_next_event(NULL);
 }
 
-static void clock_was_set_work(struct work_struct *work)
-{
-	clock_was_set();
-}
-
-static DECLARE_WORK(hrtimer_work, clock_was_set_work);
-
-/*
- * Called from timekeeping and resume code to reprogram the hrtimer
- * interrupt device on all cpus.
- */
-void clock_was_set_delayed(void)
-{
-	schedule_work(&hrtimer_work);
-}
-
 #else
 
 static inline int hrtimer_is_hres_enabled(void) { return 0; }
@@ -877,6 +861,22 @@ void clock_was_set(void)
 	timerfd_clock_was_set();
 }
 
+static void clock_was_set_work(struct work_struct *work)
+{
+	clock_was_set();
+}
+
+static DECLARE_WORK(hrtimer_work, clock_was_set_work);
+
+/*
+ * Called from timekeeping and resume code to reprogram the hrtimer
+ * interrupt device on all cpus and to notify timerfd.
+ */
+void clock_was_set_delayed(void)
+{
+	schedule_work(&hrtimer_work);
+}
+
 /*
  * During resume we might have to reprogram the high resolution timer
  * interrupt on all online CPUs.  However, all other CPUs will be
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -165,3 +165,6 @@ DECLARE_PER_CPU(struct hrtimer_cpu_base,
 
 extern u64 get_next_timer_interrupt(unsigned long basej, u64 basem);
 void timer_clear_idle(void);
+
+void clock_was_set(void);
+void clock_was_set_delayed(void);