[PATCH] hrtimers: cleanup locking (3c8aa39d) · Commits · e / devices / android_kernel_oneplus_sm7250

include/linux/hrtimer.h

+28 −15

Original line number	Diff line number	Diff line
		@@ -21,6 +21,9 @@
		#include <linux/list.h>
		#include <linux/wait.h>

		struct hrtimer_clock_base;
		struct hrtimer_cpu_base;

		/*
		* Mode arguments of xxx_hrtimer functions:
		*/
		@@ -37,8 +40,6 @@ enum hrtimer_restart {
		HRTIMER_RESTART, /* Timer must be restarted */
		};

		struct hrtimer_base;

		/**
		* struct hrtimer - the basic hrtimer structure
		* @node: red black tree node for time ordered insertion
		@@ -54,7 +55,7 @@ struct hrtimer {
		struct rb_node node;
		ktime_t expires;
		enum hrtimer_restart (function)(struct hrtimer );
		struct hrtimer_base *base;
		struct hrtimer_clock_base *base;
		};

		/**
		@@ -71,29 +72,41 @@ struct hrtimer_sleeper {

		/**
		* struct hrtimer_base - the timer base for a specific clock
		* @index: clock type index for per_cpu support when moving a timer
		* to a base on another cpu.
		* @lock: lock protecting the base and associated timers
		* @index: clock type index for per_cpu support when moving a
		* timer to a base on another cpu.
		* @active: red black tree root node for the active timers
		* @first: pointer to the timer node which expires first
		* @resolution: the resolution of the clock, in nanoseconds
		* @get_time: function to retrieve the current time of the clock
		* @get_softirq_time: function to retrieve the current time from the softirq
		* @curr_timer: the timer which is executing a callback right now
		* @softirq_time: the time when running the hrtimer queue in the softirq
		* @lock_key: the lock_class_key for use with lockdep
		*/
		struct hrtimer_base {
		struct hrtimer_clock_base {
		struct hrtimer_cpu_base *cpu_base;
		clockid_t index;
		spinlock_t lock;
		struct rb_root active;
		struct rb_node *first;
		ktime_t resolution;
		ktime_t (*get_time)(void);
		ktime_t (*get_softirq_time)(void);
		struct hrtimer *curr_timer;
		ktime_t softirq_time;
		};

		#define HRTIMER_MAX_CLOCK_BASES 2

		/*
		* struct hrtimer_cpu_base - the per cpu clock bases
		* @lock: lock protecting the base and associated clock bases
		* and timers
		* @lock_key: the lock_class_key for use with lockdep
		* @clock_base: array of clock bases for this cpu
		* @curr_timer: the timer which is executing a callback right now
		*/
		struct hrtimer_cpu_base {
		spinlock_t lock;
		struct lock_class_key lock_key;
		struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
		struct hrtimer *curr_timer;
		};

		/*

kernel/hrtimer.c

+98 −86

Original line number	Diff line number	Diff line
		/*
		* linux/kernel/hrtimer.c
		*
		* Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
		* Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
		* Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
		* Copyright(C) 2005-2006, Red Hat, Inc., Ingo Molnar
		* Copyright(C) 2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
		*
		* High-resolution kernel timers
		*
		@@ -79,10 +80,10 @@ EXPORT_SYMBOL_GPL(ktime_get_real);
		* This ensures that we capture erroneous accesses to these clock ids
		* rather than moving them into the range of valid clock id's.
		*/
		static DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
		{

		#define MAX_HRTIMER_BASES 2

		static DEFINE_PER_CPU(struct hrtimer_base, hrtimer_bases[MAX_HRTIMER_BASES]) =
		.clock_base =
		{
		{
		.index = CLOCK_REALTIME,
		@@ -94,6 +95,7 @@ static DEFINE_PER_CPU(struct hrtimer_base, hrtimer_bases[MAX_HRTIMER_BASES]) =
		.get_time = &ktime_get,
		.resolution = KTIME_MONOTONIC_RES,
		},
		}
		};

		/**
		@@ -125,7 +127,7 @@ EXPORT_SYMBOL_GPL(ktime_get_ts);
		* Get the coarse grained time at the softirq based on xtime and
		* wall_to_monotonic.
		*/
		static void hrtimer_get_softirq_time(struct hrtimer_base *base)
		static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
		{
		ktime_t xtim, tomono;
		struct timespec xts;
		@@ -142,8 +144,9 @@ static void hrtimer_get_softirq_time(struct hrtimer_base *base)

		xtim = timespec_to_ktime(xts);
		tomono = timespec_to_ktime(wall_to_monotonic);
		base[CLOCK_REALTIME].softirq_time = xtim;
		base[CLOCK_MONOTONIC].softirq_time = ktime_add(xtim, tomono);
		base->clock_base[CLOCK_REALTIME].softirq_time = xtim;
		base->clock_base[CLOCK_MONOTONIC].softirq_time =
		ktime_add(xtim, tomono);
		}

		/*
		@@ -166,19 +169,20 @@ static void hrtimer_get_softirq_time(struct hrtimer_base *base)
		* possible to set timer->base = NULL and drop the lock: the timer remains
		* locked.
		*/
		static struct hrtimer_base lock_hrtimer_base(const struct hrtimer timer,
		static
		struct hrtimer_clock_base lock_hrtimer_base(const struct hrtimer timer,
		unsigned long *flags)
		{
		struct hrtimer_base *base;
		struct hrtimer_clock_base *base;

		for (;;) {
		base = timer->base;
		if (likely(base != NULL)) {
		spin_lock_irqsave(&base->lock, *flags);
		spin_lock_irqsave(&base->cpu_base->lock, *flags);
		if (likely(base == timer->base))
		return base;
		/* The timer has migrated to another CPU: */
		spin_unlock_irqrestore(&base->lock, *flags);
		spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
		}
		cpu_relax();
		}
		@@ -187,12 +191,14 @@ static struct hrtimer_base lock_hrtimer_base(const struct hrtimer timer,
		/*
		* Switch the timer base to the current CPU when possible.
		*/
		static inline struct hrtimer_base *
		switch_hrtimer_base(struct hrtimer timer, struct hrtimer_base base)
		static inline struct hrtimer_clock_base *
		switch_hrtimer_base(struct hrtimer timer, struct hrtimer_clock_base base)
		{
		struct hrtimer_base *new_base;
		struct hrtimer_clock_base *new_base;
		struct hrtimer_cpu_base *new_cpu_base;

		new_base = &__get_cpu_var(hrtimer_bases)[base->index];
		new_cpu_base = &__get_cpu_var(hrtimer_bases);
		new_base = &new_cpu_base->clock_base[base->index];

		if (base != new_base) {
		/*
		@@ -204,13 +210,13 @@ switch_hrtimer_base(struct hrtimer timer, struct hrtimer_base base)
		* completed. There is no conflict as we hold the lock until
		* the timer is enqueued.
		*/
		if (unlikely(base->curr_timer == timer))
		if (unlikely(base->cpu_base->curr_timer == timer))
		return base;

		/* See the comment in lock_timer_base() */
		timer->base = NULL;
		spin_unlock(&base->lock);
		spin_lock(&new_base->lock);
		spin_unlock(&base->cpu_base->lock);
		spin_lock(&new_base->cpu_base->lock);
		timer->base = new_base;
		}
		return new_base;
		@@ -220,12 +226,12 @@ switch_hrtimer_base(struct hrtimer timer, struct hrtimer_base base)

		#define set_curr_timer(b, t) do { } while (0)

		static inline struct hrtimer_base *
		static inline struct hrtimer_clock_base *
		lock_hrtimer_base(const struct hrtimer timer, unsigned long flags)
		{
		struct hrtimer_base *base = timer->base;
		struct hrtimer_clock_base *base = timer->base;

		spin_lock_irqsave(&base->lock, *flags);
		spin_lock_irqsave(&base->cpu_base->lock, *flags);

		return base;
		}
		@@ -305,7 +311,7 @@ void hrtimer_notify_resume(void)
		static inline
		void unlock_hrtimer_base(const struct hrtimer timer, unsigned long flags)
		{
		spin_unlock_irqrestore(&timer->base->lock, *flags);
		spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);
		}

		/**
		@@ -355,7 +361,8 @@ hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
		* The timer is inserted in expiry order. Insertion into the
		* red black tree is O(log(n)). Must hold the base lock.
		*/
		static void enqueue_hrtimer(struct hrtimer timer, struct hrtimer_base base)
		static void enqueue_hrtimer(struct hrtimer *timer,
		struct hrtimer_clock_base *base)
		{
		struct rb_node **link = &base->active.rb_node;
		struct rb_node *parent = NULL;
		@@ -394,7 +401,8 @@ static void enqueue_hrtimer(struct hrtimer timer, struct hrtimer_base base)
		*
		* Caller must hold the base lock.
		*/
		static void __remove_hrtimer(struct hrtimer timer, struct hrtimer_base base)
		static void __remove_hrtimer(struct hrtimer *timer,
		struct hrtimer_clock_base *base)
		{
		/*
		* Remove the timer from the rbtree and replace the
		@@ -410,7 +418,7 @@ static void __remove_hrtimer(struct hrtimer timer, struct hrtimer_base base)
		* remove hrtimer, called with base lock held
		*/
		static inline int
		remove_hrtimer(struct hrtimer timer, struct hrtimer_base base)
		remove_hrtimer(struct hrtimer timer, struct hrtimer_clock_base base)
		{
		if (hrtimer_active(timer)) {
		__remove_hrtimer(timer, base);
		@@ -432,7 +440,7 @@ remove_hrtimer(struct hrtimer timer, struct hrtimer_base base)
		int
		hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
		{
		struct hrtimer_base base, new_base;
		struct hrtimer_clock_base base, new_base;
		unsigned long flags;
		int ret;

		@@ -479,13 +487,13 @@ EXPORT_SYMBOL_GPL(hrtimer_start);
		*/
		int hrtimer_try_to_cancel(struct hrtimer *timer)
		{
		struct hrtimer_base *base;
		struct hrtimer_clock_base *base;
		unsigned long flags;
		int ret = -1;

		base = lock_hrtimer_base(timer, &flags);

		if (base->curr_timer != timer)
		if (base->cpu_base->curr_timer != timer)
		ret = remove_hrtimer(timer, base);

		unlock_hrtimer_base(timer, &flags);
		@@ -521,12 +529,12 @@ EXPORT_SYMBOL_GPL(hrtimer_cancel);
		*/
		ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
		{
		struct hrtimer_base *base;
		struct hrtimer_clock_base *base;
		unsigned long flags;
		ktime_t rem;

		base = lock_hrtimer_base(timer, &flags);
		rem = ktime_sub(timer->expires, timer->base->get_time());
		rem = ktime_sub(timer->expires, base->get_time());
		unlock_hrtimer_base(timer, &flags);

		return rem;
		@@ -542,26 +550,29 @@ EXPORT_SYMBOL_GPL(hrtimer_get_remaining);
		*/
		ktime_t hrtimer_get_next_event(void)
		{
		struct hrtimer_base *base = __get_cpu_var(hrtimer_bases);
		struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
		struct hrtimer_clock_base *base = cpu_base->clock_base;
		ktime_t delta, mindelta = { .tv64 = KTIME_MAX };
		unsigned long flags;
		int i;

		for (i = 0; i < MAX_HRTIMER_BASES; i++, base++) {
		spin_lock_irqsave(&cpu_base->lock, flags);

		for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
		struct hrtimer *timer;

		spin_lock_irqsave(&base->lock, flags);
		if (!base->first) {
		spin_unlock_irqrestore(&base->lock, flags);
		if (!base->first)
		continue;
		}

		timer = rb_entry(base->first, struct hrtimer, node);
		delta.tv64 = timer->expires.tv64;
		spin_unlock_irqrestore(&base->lock, flags);
		delta = ktime_sub(delta, base->get_time());
		if (delta.tv64 < mindelta.tv64)
		mindelta.tv64 = delta.tv64;
		}

		spin_unlock_irqrestore(&cpu_base->lock, flags);

		if (mindelta.tv64 < 0)
		mindelta.tv64 = 0;
		return mindelta;
		@@ -577,16 +588,16 @@ ktime_t hrtimer_get_next_event(void)
		void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
		enum hrtimer_mode mode)
		{
		struct hrtimer_base *bases;
		struct hrtimer_cpu_base *cpu_base;

		memset(timer, 0, sizeof(struct hrtimer));

		bases = __raw_get_cpu_var(hrtimer_bases);
		cpu_base = &__raw_get_cpu_var(hrtimer_bases);

		if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS)
		clock_id = CLOCK_MONOTONIC;

		timer->base = &bases[clock_id];
		timer->base = &cpu_base->clock_base[clock_id];
		rb_set_parent(&timer->node, &timer->node);
		}
		EXPORT_SYMBOL_GPL(hrtimer_init);
		@@ -601,10 +612,10 @@ EXPORT_SYMBOL_GPL(hrtimer_init);
		*/
		int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp)
		{
		struct hrtimer_base *bases;
		struct hrtimer_cpu_base *cpu_base;

		bases = __raw_get_cpu_var(hrtimer_bases);
		*tp = ktime_to_timespec(bases[which_clock].resolution);
		cpu_base = &__raw_get_cpu_var(hrtimer_bases);
		*tp = ktime_to_timespec(cpu_base->clock_base[which_clock].resolution);

		return 0;
		}
		@@ -613,9 +624,11 @@ EXPORT_SYMBOL_GPL(hrtimer_get_res);
		/*
		* Expire the per base hrtimer-queue:
		*/
		static inline void run_hrtimer_queue(struct hrtimer_base *base)
		static inline void run_hrtimer_queue(struct hrtimer_cpu_base *cpu_base,
		int index)
		{
		struct rb_node *node;
		struct hrtimer_clock_base *base = &cpu_base->clock_base[index];

		if (!base->first)
		return;
		@@ -623,7 +636,7 @@ static inline void run_hrtimer_queue(struct hrtimer_base *base)
		if (base->get_softirq_time)
		base->softirq_time = base->get_softirq_time();

		spin_lock_irq(&base->lock);
		spin_lock_irq(&cpu_base->lock);

		while ((node = base->first)) {
		struct hrtimer *timer;
		@@ -635,21 +648,21 @@ static inline void run_hrtimer_queue(struct hrtimer_base *base)
		break;

		fn = timer->function;
		set_curr_timer(base, timer);
		set_curr_timer(cpu_base, timer);
		__remove_hrtimer(timer, base);
		spin_unlock_irq(&base->lock);
		spin_unlock_irq(&cpu_base->lock);

		restart = fn(timer);

		spin_lock_irq(&base->lock);
		spin_lock_irq(&cpu_base->lock);

		if (restart != HRTIMER_NORESTART) {
		BUG_ON(hrtimer_active(timer));
		enqueue_hrtimer(timer, base);
		}
		}
		set_curr_timer(base, NULL);
		spin_unlock_irq(&base->lock);
		set_curr_timer(cpu_base, NULL);
		spin_unlock_irq(&cpu_base->lock);
		}

		/*
		@@ -657,13 +670,13 @@ static inline void run_hrtimer_queue(struct hrtimer_base *base)
		*/
		void hrtimer_run_queues(void)
		{
		struct hrtimer_base *base = __get_cpu_var(hrtimer_bases);
		struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
		int i;

		hrtimer_get_softirq_time(base);
		hrtimer_get_softirq_time(cpu_base);

		for (i = 0; i < MAX_HRTIMER_BASES; i++)
		run_hrtimer_queue(&base[i]);
		for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
		run_hrtimer_queue(cpu_base, i);
		}

		/*
		@@ -792,19 +805,21 @@ sys_nanosleep(struct timespec __user rqtp, struct timespec __user rmtp)
		*/
		static void __devinit init_hrtimers_cpu(int cpu)
		{
		struct hrtimer_base *base = per_cpu(hrtimer_bases, cpu);
		struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
		int i;

		for (i = 0; i < MAX_HRTIMER_BASES; i++, base++) {
		spin_lock_init(&base->lock);
		lockdep_set_class(&base->lock, &base->lock_key);
		}
		spin_lock_init(&cpu_base->lock);
		lockdep_set_class(&cpu_base->lock, &cpu_base->lock_key);

		for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
		cpu_base->clock_base[i].cpu_base = cpu_base;

		}

		#ifdef CONFIG_HOTPLUG_CPU

		static void migrate_hrtimer_list(struct hrtimer_base *old_base,
		struct hrtimer_base *new_base)
		static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
		struct hrtimer_clock_base *new_base)
		{
		struct hrtimer *timer;
		struct rb_node *node;
		@@ -819,29 +834,26 @@ static void migrate_hrtimer_list(struct hrtimer_base *old_base,

		static void migrate_hrtimers(int cpu)
		{
		struct hrtimer_base old_base, new_base;
		struct hrtimer_cpu_base old_base, new_base;
		int i;

		BUG_ON(cpu_online(cpu));
		old_base = per_cpu(hrtimer_bases, cpu);
		new_base = get_cpu_var(hrtimer_bases);
		old_base = &per_cpu(hrtimer_bases, cpu);
		new_base = &get_cpu_var(hrtimer_bases);

		local_irq_disable();

		for (i = 0; i < MAX_HRTIMER_BASES; i++) {

		spin_lock(&new_base->lock);
		spin_lock(&old_base->lock);

		for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
		BUG_ON(old_base->curr_timer);

		migrate_hrtimer_list(old_base, new_base);

		migrate_hrtimer_list(&old_base->clock_base[i],
		&new_base->clock_base[i]);
		}
		spin_unlock(&old_base->lock);
		spin_unlock(&new_base->lock);
		old_base++;
		new_base++;
		}

		local_irq_enable();
		put_cpu_var(hrtimer_bases);