From: Thomas Gleixner clockevents_notify() is a leftover from the early design of the clockevents facility. It's really not a notification mechanism, it's a multiplex call. We are way better off to have explicit calls instead of this monstrosity. Split out the broadcast oneshot control into a separate function and provide inline helpers. Switch clockevents_notify() over. This will go away once all callers are converted. This also gets rid of the nested locking of clockevents_lock and broadcast_lock. The broadcast oneshot control functions do not require clockevents_lock. Only the managing functions (setup/shutdown/suspend/resume of the broadcast device require clockevents_lock. Signed-off-by: Thomas Gleixner Cc: Tony Lindgren Cc: Stephen Warren Cc: Thierry Reding Cc: Alexandre Courbot Cc: Daniel Lezcano Cc: "Rafael J. Wysocki" Cc: Fenghua Yu Cc: Len Brown --- include/linux/tick.h | 19 +++++++++++++++++++ kernel/time/clockevents.c | 4 +++- kernel/time/tick-broadcast.c | 28 +++++++++++++++++----------- kernel/time/tick-internal.h | 2 -- 4 files changed, 39 insertions(+), 14 deletions(-) Index: linux/include/linux/tick.h =================================================================== --- linux.orig/include/linux/tick.h +++ linux/include/linux/tick.h @@ -53,12 +53,23 @@ enum tick_broadcast_mode { TICK_BROADCAST_FORCE, }; +enum tick_broadcast_state { + TICK_BROADCAST_EXIT, + TICK_BROADCAST_ENTER, +}; + #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST extern void tick_broadcast_control(enum tick_broadcast_mode mode); #else static inline void tick_broadcast_control(enum tick_broadcast_mode mode) { } #endif /* BROADCAST */ +#if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT) +extern int tick_broadcast_oneshot_control(enum tick_broadcast_state state); +#else +static inline int tick_broadcast_oneshot_control(enum tick_broadcast_state state) { return 0; } +#endif + static inline void tick_broadcast_enable(void) { tick_broadcast_control(TICK_BROADCAST_ON); @@ -71,6 +82,14 @@ static inline void tick_broadcast_force( { tick_broadcast_control(TICK_BROADCAST_FORCE); } +static inline int tick_broadcast_enter(void) +{ + return tick_broadcast_oneshot_control(TICK_BROADCAST_ENTER); +} +static inline void tick_broadcast_exit(void) +{ + tick_broadcast_oneshot_control(TICK_BROADCAST_EXIT); +} #ifdef CONFIG_NO_HZ_COMMON extern int tick_nohz_tick_stopped(void); Index: linux/kernel/time/clockevents.c =================================================================== --- linux.orig/kernel/time/clockevents.c +++ linux/kernel/time/clockevents.c @@ -586,8 +586,10 @@ int clockevents_notify(unsigned long rea switch (reason) { case CLOCK_EVT_NOTIFY_BROADCAST_ENTER: + tick_broadcast_enter(); + break; case CLOCK_EVT_NOTIFY_BROADCAST_EXIT: - ret = tick_broadcast_oneshot_control(reason); + tick_broadcast_exit(); break; default: Index: linux/kernel/time/tick-broadcast.c =================================================================== --- linux.orig/kernel/time/tick-broadcast.c +++ linux/kernel/time/tick-broadcast.c @@ -676,18 +676,23 @@ static void broadcast_shutdown_local(str clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN); } -/* - * Powerstate information: The system enters/leaves a state, where - * affected devices might stop +/** + * tick_broadcast_oneshot_control - Enter/exit broadcast oneshot mode + * @state: The target state (enter/exit) + * + * The system enters/leaves a state, where affected devices might stop * Returns 0 on success, -EBUSY if the cpu is used to broadcast wakeups. + * + * Called with interrupts disabled, so clockevents_lock is not + * required here because the local clock event device cannot go away + * under us. */ -int tick_broadcast_oneshot_control(unsigned long reason) +int tick_broadcast_oneshot_control(enum tick_broadcast_state state) { struct clock_event_device *bc, *dev; struct tick_device *td; - unsigned long flags; - ktime_t now; int cpu, ret = 0; + ktime_t now; /* * Periodic mode does not care about the enter/exit of power @@ -700,17 +705,17 @@ int tick_broadcast_oneshot_control(unsig * We are called with preemtion disabled from the depth of the * idle code, so we can't be moved away. */ - cpu = smp_processor_id(); - td = &per_cpu(tick_cpu_device, cpu); + td = this_cpu_ptr(&tick_cpu_device); dev = td->evtdev; if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) return 0; + raw_spin_lock(&tick_broadcast_lock); bc = tick_broadcast_device.evtdev; + cpu = smp_processor_id(); - raw_spin_lock_irqsave(&tick_broadcast_lock, flags); - if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) { + if (state == TICK_BROADCAST_ENTER) { if (!cpumask_test_and_set_cpu(cpu, tick_broadcast_oneshot_mask)) { WARN_ON_ONCE(cpumask_test_cpu(cpu, tick_broadcast_pending_mask)); broadcast_shutdown_local(bc, dev); @@ -802,9 +807,10 @@ int tick_broadcast_oneshot_control(unsig } } out: - raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); + raw_spin_unlock(&tick_broadcast_lock); return ret; } +EXPORT_SYMBOL_GPL(tick_broadcast_oneshot_control); /* * Reset the one shot broadcast for a cpu Index: linux/kernel/time/tick-internal.h =================================================================== --- linux.orig/kernel/time/tick-internal.h +++ linux/kernel/time/tick-internal.h @@ -109,7 +109,6 @@ static inline void tick_set_periodic_han /* Functions related to oneshot broadcasting */ #if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT) extern void tick_broadcast_setup_oneshot(struct clock_event_device *bc); -extern int tick_broadcast_oneshot_control(unsigned long reason); extern void tick_broadcast_switch_to_oneshot(void); extern void tick_shutdown_broadcast_oneshot(unsigned int cpu); extern int tick_broadcast_oneshot_active(void); @@ -118,7 +117,6 @@ bool tick_broadcast_oneshot_available(vo extern struct cpumask *tick_get_broadcast_oneshot_mask(void); #else /* BROADCAST && ONESHOT */ static inline void tick_broadcast_setup_oneshot(struct clock_event_device *bc) { BUG(); } -static inline int tick_broadcast_oneshot_control(unsigned long reason) { return 0; } static inline void tick_broadcast_switch_to_oneshot(void) { } static inline void tick_shutdown_broadcast_oneshot(unsigned int cpu) { } static inline int tick_broadcast_oneshot_active(void) { return 0; }