Upon adjustments of the monotonic clock's frequencies from the
timekeeping core, the clockevents devices' ->mult_adjusted should be
changed accordingly, too.

Introduce clockevents_adjust_all_freqs() which traverses all registered
clockevent devices and, if the CLOCK_EVT_FEAT_NO_ADJUST flag is not set,
recalculates their ->mult_adjusted based on the monotonic clock's current
frequency.

Call clockevents_adjust_all_freqs() from timekeeping_apply_adjustment().

Signed-off-by: Nicolai Stange <[email protected]>
---
 kernel/time/clockevents.c   | 33 +++++++++++++++++++++++++++++++++
 kernel/time/tick-internal.h |  5 +++++
 kernel/time/timekeeping.c   |  3 +++
 3 files changed, 41 insertions(+)

diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index c8b2df8..40ee5b2 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -626,6 +626,39 @@ void __clockevents_adjust_freq(struct clock_event_device 
*dev)
                                                        mult_cs_raw);
 }
 
+void clockevents_adjust_all_freqs(u32 mult_cs_mono, u32 mult_cs_raw)
+{
+       u32 last_mult_raw = 0, last_shift = 0, last_mult_adjusted = 0;
+       u32 mult_raw, shift;
+       unsigned long flags;
+       struct clock_event_device *dev;
+
+       raw_spin_lock_irqsave(&clockevents_lock, flags);
+       list_for_each_entry(dev, &clockevent_devices, list) {
+               if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT) ||
+                    (dev->features & CLOCK_EVT_FEAT_NO_ADJUST))
+                       continue;
+
+               /*
+                * The cached last_mult_adjusted is only valid if
+                * shift == last_shift. Otherwise, it could exceed
+                * what is allowed by ->max_delta_ns.
+                */
+               mult_raw = dev->mult;
+               shift = dev->shift;
+               if (mult_raw != last_mult_raw || shift != last_shift) {
+                       last_mult_raw = mult_raw;
+                       last_shift = shift;
+                       last_mult_adjusted =
+                               __clockevents_calc_adjust_freq(mult_raw,
+                                                       mult_cs_mono,
+                                                       mult_cs_raw);
+               }
+               dev->mult_adjusted = last_mult_adjusted;
+       }
+       raw_spin_unlock_irqrestore(&clockevents_lock, flags);
+}
+
 int __clockevents_update_freq(struct clock_event_device *dev, u32 freq)
 {
        clockevents_config(dev, freq);
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index 0b29d23..2d97c42 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -56,6 +56,7 @@ extern int clockevents_program_event(struct 
clock_event_device *dev,
                                     ktime_t expires, bool force);
 extern void clockevents_handle_noop(struct clock_event_device *dev);
 extern int __clockevents_update_freq(struct clock_event_device *dev, u32 freq);
+extern void clockevents_adjust_all_freqs(u32 mult_cs_mono, u32 mult_cs_raw);
 extern void timekeeping_get_mono_mult(u32 *mult_cs_mono, u32 *mult_cs_raw);
 extern ssize_t sysfs_get_uname(const char *buf, char *dst, size_t cnt);
 
@@ -95,6 +96,10 @@ static inline void tick_set_periodic_handler(struct 
clock_event_device *dev, int
 #else /* !GENERIC_CLOCKEVENTS: */
 static inline void tick_suspend(void) { }
 static inline void tick_resume(void) { }
+
+static inline void clockevents_adjust_all_freqs(u32 mult_cs_mono,
+                                               u32 mult_cs_raw)
+{}
 #endif /* !GENERIC_CLOCKEVENTS */
 
 /* Oneshot related functions */
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index bd12861..6b3f2bc 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1850,6 +1850,9 @@ static __always_inline void 
timekeeping_apply_adjustment(struct timekeeper *tk,
        tk->xtime_interval += interval;
        tk->tkr_mono.xtime_nsec -= offset;
        tk->ntp_error -= (interval - offset) << tk->ntp_error_shift;
+
+       clockevents_adjust_all_freqs(tk->tkr_mono.mult,
+                               tk->tkr_mono.clock->mult);
 }
 
 /*
-- 
2.9.3

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