v4.19.13 snapshot.
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
new file mode 100644
index 0000000..fa49cd7
--- /dev/null
+++ b/kernel/time/timer.c
@@ -0,0 +1,1999 @@
+/*
+ * linux/kernel/timer.c
+ *
+ * Kernel internal timers
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ * 1997-01-28 Modified by Finn Arne Gangstad to make timers scale better.
+ *
+ * 1997-09-10 Updated NTP code according to technical memorandum Jan '96
+ * "A Kernel Model for Precision Timekeeping" by Dave Mills
+ * 1998-12-24 Fixed a xtime SMP race (we need the xtime_lock rw spinlock to
+ * serialize accesses to xtime/lost_ticks).
+ * Copyright (C) 1998 Andrea Arcangeli
+ * 1999-03-10 Improved NTP compatibility by Ulrich Windl
+ * 2002-05-31 Move sys_sysinfo here and make its locking sane, Robert Love
+ * 2000-10-05 Implemented scalable SMP per-CPU timer handling.
+ * Copyright (C) 2000, 2001, 2002 Ingo Molnar
+ * Designed by David S. Miller, Alexey Kuznetsov and Ingo Molnar
+ */
+
+#include <linux/kernel_stat.h>
+#include <linux/export.h>
+#include <linux/interrupt.h>
+#include <linux/percpu.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/pid_namespace.h>
+#include <linux/notifier.h>
+#include <linux/thread_info.h>
+#include <linux/time.h>
+#include <linux/jiffies.h>
+#include <linux/posix-timers.h>
+#include <linux/cpu.h>
+#include <linux/syscalls.h>
+#include <linux/delay.h>
+#include <linux/tick.h>
+#include <linux/kallsyms.h>
+#include <linux/irq_work.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/sysctl.h>
+#include <linux/sched/nohz.h>
+#include <linux/sched/debug.h>
+#include <linux/slab.h>
+#include <linux/compat.h>
+
+#include <linux/uaccess.h>
+#include <asm/unistd.h>
+#include <asm/div64.h>
+#include <asm/timex.h>
+#include <asm/io.h>
+
+#include "tick-internal.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/timer.h>
+
+__visible u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;
+
+EXPORT_SYMBOL(jiffies_64);
+
+/*
+ * The timer wheel has LVL_DEPTH array levels. Each level provides an array of
+ * LVL_SIZE buckets. Each level is driven by its own clock and therefor each
+ * level has a different granularity.
+ *
+ * The level granularity is: LVL_CLK_DIV ^ lvl
+ * The level clock frequency is: HZ / (LVL_CLK_DIV ^ level)
+ *
+ * The array level of a newly armed timer depends on the relative expiry
+ * time. The farther the expiry time is away the higher the array level and
+ * therefor the granularity becomes.
+ *
+ * Contrary to the original timer wheel implementation, which aims for 'exact'
+ * expiry of the timers, this implementation removes the need for recascading
+ * the timers into the lower array levels. The previous 'classic' timer wheel
+ * implementation of the kernel already violated the 'exact' expiry by adding
+ * slack to the expiry time to provide batched expiration. The granularity
+ * levels provide implicit batching.
+ *
+ * This is an optimization of the original timer wheel implementation for the
+ * majority of the timer wheel use cases: timeouts. The vast majority of
+ * timeout timers (networking, disk I/O ...) are canceled before expiry. If
+ * the timeout expires it indicates that normal operation is disturbed, so it
+ * does not matter much whether the timeout comes with a slight delay.
+ *
+ * The only exception to this are networking timers with a small expiry
+ * time. They rely on the granularity. Those fit into the first wheel level,
+ * which has HZ granularity.
+ *
+ * We don't have cascading anymore. timers with a expiry time above the
+ * capacity of the last wheel level are force expired at the maximum timeout
+ * value of the last wheel level. From data sampling we know that the maximum
+ * value observed is 5 days (network connection tracking), so this should not
+ * be an issue.
+ *
+ * The currently chosen array constants values are a good compromise between
+ * array size and granularity.
+ *
+ * This results in the following granularity and range levels:
+ *
+ * HZ 1000 steps
+ * Level Offset Granularity Range
+ * 0 0 1 ms 0 ms - 63 ms
+ * 1 64 8 ms 64 ms - 511 ms
+ * 2 128 64 ms 512 ms - 4095 ms (512ms - ~4s)
+ * 3 192 512 ms 4096 ms - 32767 ms (~4s - ~32s)
+ * 4 256 4096 ms (~4s) 32768 ms - 262143 ms (~32s - ~4m)
+ * 5 320 32768 ms (~32s) 262144 ms - 2097151 ms (~4m - ~34m)
+ * 6 384 262144 ms (~4m) 2097152 ms - 16777215 ms (~34m - ~4h)
+ * 7 448 2097152 ms (~34m) 16777216 ms - 134217727 ms (~4h - ~1d)
+ * 8 512 16777216 ms (~4h) 134217728 ms - 1073741822 ms (~1d - ~12d)
+ *
+ * HZ 300
+ * Level Offset Granularity Range
+ * 0 0 3 ms 0 ms - 210 ms
+ * 1 64 26 ms 213 ms - 1703 ms (213ms - ~1s)
+ * 2 128 213 ms 1706 ms - 13650 ms (~1s - ~13s)
+ * 3 192 1706 ms (~1s) 13653 ms - 109223 ms (~13s - ~1m)
+ * 4 256 13653 ms (~13s) 109226 ms - 873810 ms (~1m - ~14m)
+ * 5 320 109226 ms (~1m) 873813 ms - 6990503 ms (~14m - ~1h)
+ * 6 384 873813 ms (~14m) 6990506 ms - 55924050 ms (~1h - ~15h)
+ * 7 448 6990506 ms (~1h) 55924053 ms - 447392423 ms (~15h - ~5d)
+ * 8 512 55924053 ms (~15h) 447392426 ms - 3579139406 ms (~5d - ~41d)
+ *
+ * HZ 250
+ * Level Offset Granularity Range
+ * 0 0 4 ms 0 ms - 255 ms
+ * 1 64 32 ms 256 ms - 2047 ms (256ms - ~2s)
+ * 2 128 256 ms 2048 ms - 16383 ms (~2s - ~16s)
+ * 3 192 2048 ms (~2s) 16384 ms - 131071 ms (~16s - ~2m)
+ * 4 256 16384 ms (~16s) 131072 ms - 1048575 ms (~2m - ~17m)
+ * 5 320 131072 ms (~2m) 1048576 ms - 8388607 ms (~17m - ~2h)
+ * 6 384 1048576 ms (~17m) 8388608 ms - 67108863 ms (~2h - ~18h)
+ * 7 448 8388608 ms (~2h) 67108864 ms - 536870911 ms (~18h - ~6d)
+ * 8 512 67108864 ms (~18h) 536870912 ms - 4294967288 ms (~6d - ~49d)
+ *
+ * HZ 100
+ * Level Offset Granularity Range
+ * 0 0 10 ms 0 ms - 630 ms
+ * 1 64 80 ms 640 ms - 5110 ms (640ms - ~5s)
+ * 2 128 640 ms 5120 ms - 40950 ms (~5s - ~40s)
+ * 3 192 5120 ms (~5s) 40960 ms - 327670 ms (~40s - ~5m)
+ * 4 256 40960 ms (~40s) 327680 ms - 2621430 ms (~5m - ~43m)
+ * 5 320 327680 ms (~5m) 2621440 ms - 20971510 ms (~43m - ~5h)
+ * 6 384 2621440 ms (~43m) 20971520 ms - 167772150 ms (~5h - ~1d)
+ * 7 448 20971520 ms (~5h) 167772160 ms - 1342177270 ms (~1d - ~15d)
+ */
+
+/* Clock divisor for the next level */
+#define LVL_CLK_SHIFT 3
+#define LVL_CLK_DIV (1UL << LVL_CLK_SHIFT)
+#define LVL_CLK_MASK (LVL_CLK_DIV - 1)
+#define LVL_SHIFT(n) ((n) * LVL_CLK_SHIFT)
+#define LVL_GRAN(n) (1UL << LVL_SHIFT(n))
+
+/*
+ * The time start value for each level to select the bucket at enqueue
+ * time.
+ */
+#define LVL_START(n) ((LVL_SIZE - 1) << (((n) - 1) * LVL_CLK_SHIFT))
+
+/* Size of each clock level */
+#define LVL_BITS 6
+#define LVL_SIZE (1UL << LVL_BITS)
+#define LVL_MASK (LVL_SIZE - 1)
+#define LVL_OFFS(n) ((n) * LVL_SIZE)
+
+/* Level depth */
+#if HZ > 100
+# define LVL_DEPTH 9
+# else
+# define LVL_DEPTH 8
+#endif
+
+/* The cutoff (max. capacity of the wheel) */
+#define WHEEL_TIMEOUT_CUTOFF (LVL_START(LVL_DEPTH))
+#define WHEEL_TIMEOUT_MAX (WHEEL_TIMEOUT_CUTOFF - LVL_GRAN(LVL_DEPTH - 1))
+
+/*
+ * The resulting wheel size. If NOHZ is configured we allocate two
+ * wheels so we have a separate storage for the deferrable timers.
+ */
+#define WHEEL_SIZE (LVL_SIZE * LVL_DEPTH)
+
+#ifdef CONFIG_NO_HZ_COMMON
+# define NR_BASES 2
+# define BASE_STD 0
+# define BASE_DEF 1
+#else
+# define NR_BASES 1
+# define BASE_STD 0
+# define BASE_DEF 0
+#endif
+
+struct timer_base {
+ raw_spinlock_t lock;
+ struct timer_list *running_timer;
+ unsigned long clk;
+ unsigned long next_expiry;
+ unsigned int cpu;
+ bool is_idle;
+ bool must_forward_clk;
+ DECLARE_BITMAP(pending_map, WHEEL_SIZE);
+ struct hlist_head vectors[WHEEL_SIZE];
+} ____cacheline_aligned;
+
+static DEFINE_PER_CPU(struct timer_base, timer_bases[NR_BASES]);
+
+#ifdef CONFIG_NO_HZ_COMMON
+
+static DEFINE_STATIC_KEY_FALSE(timers_nohz_active);
+static DEFINE_MUTEX(timer_keys_mutex);
+
+static void timer_update_keys(struct work_struct *work);
+static DECLARE_WORK(timer_update_work, timer_update_keys);
+
+#ifdef CONFIG_SMP
+unsigned int sysctl_timer_migration = 1;
+
+DEFINE_STATIC_KEY_FALSE(timers_migration_enabled);
+
+static void timers_update_migration(void)
+{
+ if (sysctl_timer_migration && tick_nohz_active)
+ static_branch_enable(&timers_migration_enabled);
+ else
+ static_branch_disable(&timers_migration_enabled);
+}
+#else
+static inline void timers_update_migration(void) { }
+#endif /* !CONFIG_SMP */
+
+static void timer_update_keys(struct work_struct *work)
+{
+ mutex_lock(&timer_keys_mutex);
+ timers_update_migration();
+ static_branch_enable(&timers_nohz_active);
+ mutex_unlock(&timer_keys_mutex);
+}
+
+void timers_update_nohz(void)
+{
+ schedule_work(&timer_update_work);
+}
+
+int timer_migration_handler(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp,
+ loff_t *ppos)
+{
+ int ret;
+
+ mutex_lock(&timer_keys_mutex);
+ ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+ if (!ret && write)
+ timers_update_migration();
+ mutex_unlock(&timer_keys_mutex);
+ return ret;
+}
+
+static inline bool is_timers_nohz_active(void)
+{
+ return static_branch_unlikely(&timers_nohz_active);
+}
+#else
+static inline bool is_timers_nohz_active(void) { return false; }
+#endif /* NO_HZ_COMMON */
+
+static unsigned long round_jiffies_common(unsigned long j, int cpu,
+ bool force_up)
+{
+ int rem;
+ unsigned long original = j;
+
+ /*
+ * We don't want all cpus firing their timers at once hitting the
+ * same lock or cachelines, so we skew each extra cpu with an extra
+ * 3 jiffies. This 3 jiffies came originally from the mm/ code which
+ * already did this.
+ * The skew is done by adding 3*cpunr, then round, then subtract this
+ * extra offset again.
+ */
+ j += cpu * 3;
+
+ rem = j % HZ;
+
+ /*
+ * If the target jiffie is just after a whole second (which can happen
+ * due to delays of the timer irq, long irq off times etc etc) then
+ * we should round down to the whole second, not up. Use 1/4th second
+ * as cutoff for this rounding as an extreme upper bound for this.
+ * But never round down if @force_up is set.
+ */
+ if (rem < HZ/4 && !force_up) /* round down */
+ j = j - rem;
+ else /* round up */
+ j = j - rem + HZ;
+
+ /* now that we have rounded, subtract the extra skew again */
+ j -= cpu * 3;
+
+ /*
+ * Make sure j is still in the future. Otherwise return the
+ * unmodified value.
+ */
+ return time_is_after_jiffies(j) ? j : original;
+}
+
+/**
+ * __round_jiffies - function to round jiffies to a full second
+ * @j: the time in (absolute) jiffies that should be rounded
+ * @cpu: the processor number on which the timeout will happen
+ *
+ * __round_jiffies() rounds an absolute time in the future (in jiffies)
+ * up or down to (approximately) full seconds. This is useful for timers
+ * for which the exact time they fire does not matter too much, as long as
+ * they fire approximately every X seconds.
+ *
+ * By rounding these timers to whole seconds, all such timers will fire
+ * at the same time, rather than at various times spread out. The goal
+ * of this is to have the CPU wake up less, which saves power.
+ *
+ * The exact rounding is skewed for each processor to avoid all
+ * processors firing at the exact same time, which could lead
+ * to lock contention or spurious cache line bouncing.
+ *
+ * The return value is the rounded version of the @j parameter.
+ */
+unsigned long __round_jiffies(unsigned long j, int cpu)
+{
+ return round_jiffies_common(j, cpu, false);
+}
+EXPORT_SYMBOL_GPL(__round_jiffies);
+
+/**
+ * __round_jiffies_relative - function to round jiffies to a full second
+ * @j: the time in (relative) jiffies that should be rounded
+ * @cpu: the processor number on which the timeout will happen
+ *
+ * __round_jiffies_relative() rounds a time delta in the future (in jiffies)
+ * up or down to (approximately) full seconds. This is useful for timers
+ * for which the exact time they fire does not matter too much, as long as
+ * they fire approximately every X seconds.
+ *
+ * By rounding these timers to whole seconds, all such timers will fire
+ * at the same time, rather than at various times spread out. The goal
+ * of this is to have the CPU wake up less, which saves power.
+ *
+ * The exact rounding is skewed for each processor to avoid all
+ * processors firing at the exact same time, which could lead
+ * to lock contention or spurious cache line bouncing.
+ *
+ * The return value is the rounded version of the @j parameter.
+ */
+unsigned long __round_jiffies_relative(unsigned long j, int cpu)
+{
+ unsigned long j0 = jiffies;
+
+ /* Use j0 because jiffies might change while we run */
+ return round_jiffies_common(j + j0, cpu, false) - j0;
+}
+EXPORT_SYMBOL_GPL(__round_jiffies_relative);
+
+/**
+ * round_jiffies - function to round jiffies to a full second
+ * @j: the time in (absolute) jiffies that should be rounded
+ *
+ * round_jiffies() rounds an absolute time in the future (in jiffies)
+ * up or down to (approximately) full seconds. This is useful for timers
+ * for which the exact time they fire does not matter too much, as long as
+ * they fire approximately every X seconds.
+ *
+ * By rounding these timers to whole seconds, all such timers will fire
+ * at the same time, rather than at various times spread out. The goal
+ * of this is to have the CPU wake up less, which saves power.
+ *
+ * The return value is the rounded version of the @j parameter.
+ */
+unsigned long round_jiffies(unsigned long j)
+{
+ return round_jiffies_common(j, raw_smp_processor_id(), false);
+}
+EXPORT_SYMBOL_GPL(round_jiffies);
+
+/**
+ * round_jiffies_relative - function to round jiffies to a full second
+ * @j: the time in (relative) jiffies that should be rounded
+ *
+ * round_jiffies_relative() rounds a time delta in the future (in jiffies)
+ * up or down to (approximately) full seconds. This is useful for timers
+ * for which the exact time they fire does not matter too much, as long as
+ * they fire approximately every X seconds.
+ *
+ * By rounding these timers to whole seconds, all such timers will fire
+ * at the same time, rather than at various times spread out. The goal
+ * of this is to have the CPU wake up less, which saves power.
+ *
+ * The return value is the rounded version of the @j parameter.
+ */
+unsigned long round_jiffies_relative(unsigned long j)
+{
+ return __round_jiffies_relative(j, raw_smp_processor_id());
+}
+EXPORT_SYMBOL_GPL(round_jiffies_relative);
+
+/**
+ * __round_jiffies_up - function to round jiffies up to a full second
+ * @j: the time in (absolute) jiffies that should be rounded
+ * @cpu: the processor number on which the timeout will happen
+ *
+ * This is the same as __round_jiffies() except that it will never
+ * round down. This is useful for timeouts for which the exact time
+ * of firing does not matter too much, as long as they don't fire too
+ * early.
+ */
+unsigned long __round_jiffies_up(unsigned long j, int cpu)
+{
+ return round_jiffies_common(j, cpu, true);
+}
+EXPORT_SYMBOL_GPL(__round_jiffies_up);
+
+/**
+ * __round_jiffies_up_relative - function to round jiffies up to a full second
+ * @j: the time in (relative) jiffies that should be rounded
+ * @cpu: the processor number on which the timeout will happen
+ *
+ * This is the same as __round_jiffies_relative() except that it will never
+ * round down. This is useful for timeouts for which the exact time
+ * of firing does not matter too much, as long as they don't fire too
+ * early.
+ */
+unsigned long __round_jiffies_up_relative(unsigned long j, int cpu)
+{
+ unsigned long j0 = jiffies;
+
+ /* Use j0 because jiffies might change while we run */
+ return round_jiffies_common(j + j0, cpu, true) - j0;
+}
+EXPORT_SYMBOL_GPL(__round_jiffies_up_relative);
+
+/**
+ * round_jiffies_up - function to round jiffies up to a full second
+ * @j: the time in (absolute) jiffies that should be rounded
+ *
+ * This is the same as round_jiffies() except that it will never
+ * round down. This is useful for timeouts for which the exact time
+ * of firing does not matter too much, as long as they don't fire too
+ * early.
+ */
+unsigned long round_jiffies_up(unsigned long j)
+{
+ return round_jiffies_common(j, raw_smp_processor_id(), true);
+}
+EXPORT_SYMBOL_GPL(round_jiffies_up);
+
+/**
+ * round_jiffies_up_relative - function to round jiffies up to a full second
+ * @j: the time in (relative) jiffies that should be rounded
+ *
+ * This is the same as round_jiffies_relative() except that it will never
+ * round down. This is useful for timeouts for which the exact time
+ * of firing does not matter too much, as long as they don't fire too
+ * early.
+ */
+unsigned long round_jiffies_up_relative(unsigned long j)
+{
+ return __round_jiffies_up_relative(j, raw_smp_processor_id());
+}
+EXPORT_SYMBOL_GPL(round_jiffies_up_relative);
+
+
+static inline unsigned int timer_get_idx(struct timer_list *timer)
+{
+ return (timer->flags & TIMER_ARRAYMASK) >> TIMER_ARRAYSHIFT;
+}
+
+static inline void timer_set_idx(struct timer_list *timer, unsigned int idx)
+{
+ timer->flags = (timer->flags & ~TIMER_ARRAYMASK) |
+ idx << TIMER_ARRAYSHIFT;
+}
+
+/*
+ * Helper function to calculate the array index for a given expiry
+ * time.
+ */
+static inline unsigned calc_index(unsigned expires, unsigned lvl)
+{
+ expires = (expires + LVL_GRAN(lvl)) >> LVL_SHIFT(lvl);
+ return LVL_OFFS(lvl) + (expires & LVL_MASK);
+}
+
+static int calc_wheel_index(unsigned long expires, unsigned long clk)
+{
+ unsigned long delta = expires - clk;
+ unsigned int idx;
+
+ if (delta < LVL_START(1)) {
+ idx = calc_index(expires, 0);
+ } else if (delta < LVL_START(2)) {
+ idx = calc_index(expires, 1);
+ } else if (delta < LVL_START(3)) {
+ idx = calc_index(expires, 2);
+ } else if (delta < LVL_START(4)) {
+ idx = calc_index(expires, 3);
+ } else if (delta < LVL_START(5)) {
+ idx = calc_index(expires, 4);
+ } else if (delta < LVL_START(6)) {
+ idx = calc_index(expires, 5);
+ } else if (delta < LVL_START(7)) {
+ idx = calc_index(expires, 6);
+ } else if (LVL_DEPTH > 8 && delta < LVL_START(8)) {
+ idx = calc_index(expires, 7);
+ } else if ((long) delta < 0) {
+ idx = clk & LVL_MASK;
+ } else {
+ /*
+ * Force expire obscene large timeouts to expire at the
+ * capacity limit of the wheel.
+ */
+ if (expires >= WHEEL_TIMEOUT_CUTOFF)
+ expires = WHEEL_TIMEOUT_MAX;
+
+ idx = calc_index(expires, LVL_DEPTH - 1);
+ }
+ return idx;
+}
+
+/*
+ * Enqueue the timer into the hash bucket, mark it pending in
+ * the bitmap and store the index in the timer flags.
+ */
+static void enqueue_timer(struct timer_base *base, struct timer_list *timer,
+ unsigned int idx)
+{
+ hlist_add_head(&timer->entry, base->vectors + idx);
+ __set_bit(idx, base->pending_map);
+ timer_set_idx(timer, idx);
+}
+
+static void
+__internal_add_timer(struct timer_base *base, struct timer_list *timer)
+{
+ unsigned int idx;
+
+ idx = calc_wheel_index(timer->expires, base->clk);
+ enqueue_timer(base, timer, idx);
+}
+
+static void
+trigger_dyntick_cpu(struct timer_base *base, struct timer_list *timer)
+{
+ if (!is_timers_nohz_active())
+ return;
+
+ /*
+ * TODO: This wants some optimizing similar to the code below, but we
+ * will do that when we switch from push to pull for deferrable timers.
+ */
+ if (timer->flags & TIMER_DEFERRABLE) {
+ if (tick_nohz_full_cpu(base->cpu))
+ wake_up_nohz_cpu(base->cpu);
+ return;
+ }
+
+ /*
+ * We might have to IPI the remote CPU if the base is idle and the
+ * timer is not deferrable. If the other CPU is on the way to idle
+ * then it can't set base->is_idle as we hold the base lock:
+ */
+ if (!base->is_idle)
+ return;
+
+ /* Check whether this is the new first expiring timer: */
+ if (time_after_eq(timer->expires, base->next_expiry))
+ return;
+
+ /*
+ * Set the next expiry time and kick the CPU so it can reevaluate the
+ * wheel:
+ */
+ base->next_expiry = timer->expires;
+ wake_up_nohz_cpu(base->cpu);
+}
+
+static void
+internal_add_timer(struct timer_base *base, struct timer_list *timer)
+{
+ __internal_add_timer(base, timer);
+ trigger_dyntick_cpu(base, timer);
+}
+
+#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
+
+static struct debug_obj_descr timer_debug_descr;
+
+static void *timer_debug_hint(void *addr)
+{
+ return ((struct timer_list *) addr)->function;
+}
+
+static bool timer_is_static_object(void *addr)
+{
+ struct timer_list *timer = addr;
+
+ return (timer->entry.pprev == NULL &&
+ timer->entry.next == TIMER_ENTRY_STATIC);
+}
+
+/*
+ * fixup_init is called when:
+ * - an active object is initialized
+ */
+static bool timer_fixup_init(void *addr, enum debug_obj_state state)
+{
+ struct timer_list *timer = addr;
+
+ switch (state) {
+ case ODEBUG_STATE_ACTIVE:
+ del_timer_sync(timer);
+ debug_object_init(timer, &timer_debug_descr);
+ return true;
+ default:
+ return false;
+ }
+}
+
+/* Stub timer callback for improperly used timers. */
+static void stub_timer(struct timer_list *unused)
+{
+ WARN_ON(1);
+}
+
+/*
+ * fixup_activate is called when:
+ * - an active object is activated
+ * - an unknown non-static object is activated
+ */
+static bool timer_fixup_activate(void *addr, enum debug_obj_state state)
+{
+ struct timer_list *timer = addr;
+
+ switch (state) {
+ case ODEBUG_STATE_NOTAVAILABLE:
+ timer_setup(timer, stub_timer, 0);
+ return true;
+
+ case ODEBUG_STATE_ACTIVE:
+ WARN_ON(1);
+
+ default:
+ return false;
+ }
+}
+
+/*
+ * fixup_free is called when:
+ * - an active object is freed
+ */
+static bool timer_fixup_free(void *addr, enum debug_obj_state state)
+{
+ struct timer_list *timer = addr;
+
+ switch (state) {
+ case ODEBUG_STATE_ACTIVE:
+ del_timer_sync(timer);
+ debug_object_free(timer, &timer_debug_descr);
+ return true;
+ default:
+ return false;
+ }
+}
+
+/*
+ * fixup_assert_init is called when:
+ * - an untracked/uninit-ed object is found
+ */
+static bool timer_fixup_assert_init(void *addr, enum debug_obj_state state)
+{
+ struct timer_list *timer = addr;
+
+ switch (state) {
+ case ODEBUG_STATE_NOTAVAILABLE:
+ timer_setup(timer, stub_timer, 0);
+ return true;
+ default:
+ return false;
+ }
+}
+
+static struct debug_obj_descr timer_debug_descr = {
+ .name = "timer_list",
+ .debug_hint = timer_debug_hint,
+ .is_static_object = timer_is_static_object,
+ .fixup_init = timer_fixup_init,
+ .fixup_activate = timer_fixup_activate,
+ .fixup_free = timer_fixup_free,
+ .fixup_assert_init = timer_fixup_assert_init,
+};
+
+static inline void debug_timer_init(struct timer_list *timer)
+{
+ debug_object_init(timer, &timer_debug_descr);
+}
+
+static inline void debug_timer_activate(struct timer_list *timer)
+{
+ debug_object_activate(timer, &timer_debug_descr);
+}
+
+static inline void debug_timer_deactivate(struct timer_list *timer)
+{
+ debug_object_deactivate(timer, &timer_debug_descr);
+}
+
+static inline void debug_timer_free(struct timer_list *timer)
+{
+ debug_object_free(timer, &timer_debug_descr);
+}
+
+static inline void debug_timer_assert_init(struct timer_list *timer)
+{
+ debug_object_assert_init(timer, &timer_debug_descr);
+}
+
+static void do_init_timer(struct timer_list *timer,
+ void (*func)(struct timer_list *),
+ unsigned int flags,
+ const char *name, struct lock_class_key *key);
+
+void init_timer_on_stack_key(struct timer_list *timer,
+ void (*func)(struct timer_list *),
+ unsigned int flags,
+ const char *name, struct lock_class_key *key)
+{
+ debug_object_init_on_stack(timer, &timer_debug_descr);
+ do_init_timer(timer, func, flags, name, key);
+}
+EXPORT_SYMBOL_GPL(init_timer_on_stack_key);
+
+void destroy_timer_on_stack(struct timer_list *timer)
+{
+ debug_object_free(timer, &timer_debug_descr);
+}
+EXPORT_SYMBOL_GPL(destroy_timer_on_stack);
+
+#else
+static inline void debug_timer_init(struct timer_list *timer) { }
+static inline void debug_timer_activate(struct timer_list *timer) { }
+static inline void debug_timer_deactivate(struct timer_list *timer) { }
+static inline void debug_timer_assert_init(struct timer_list *timer) { }
+#endif
+
+static inline void debug_init(struct timer_list *timer)
+{
+ debug_timer_init(timer);
+ trace_timer_init(timer);
+}
+
+static inline void
+debug_activate(struct timer_list *timer, unsigned long expires)
+{
+ debug_timer_activate(timer);
+ trace_timer_start(timer, expires, timer->flags);
+}
+
+static inline void debug_deactivate(struct timer_list *timer)
+{
+ debug_timer_deactivate(timer);
+ trace_timer_cancel(timer);
+}
+
+static inline void debug_assert_init(struct timer_list *timer)
+{
+ debug_timer_assert_init(timer);
+}
+
+static void do_init_timer(struct timer_list *timer,
+ void (*func)(struct timer_list *),
+ unsigned int flags,
+ const char *name, struct lock_class_key *key)
+{
+ timer->entry.pprev = NULL;
+ timer->function = func;
+ timer->flags = flags | raw_smp_processor_id();
+ lockdep_init_map(&timer->lockdep_map, name, key, 0);
+}
+
+/**
+ * init_timer_key - initialize a timer
+ * @timer: the timer to be initialized
+ * @func: timer callback function
+ * @flags: timer flags
+ * @name: name of the timer
+ * @key: lockdep class key of the fake lock used for tracking timer
+ * sync lock dependencies
+ *
+ * init_timer_key() must be done to a timer prior calling *any* of the
+ * other timer functions.
+ */
+void init_timer_key(struct timer_list *timer,
+ void (*func)(struct timer_list *), unsigned int flags,
+ const char *name, struct lock_class_key *key)
+{
+ debug_init(timer);
+ do_init_timer(timer, func, flags, name, key);
+}
+EXPORT_SYMBOL(init_timer_key);
+
+static inline void detach_timer(struct timer_list *timer, bool clear_pending)
+{
+ struct hlist_node *entry = &timer->entry;
+
+ debug_deactivate(timer);
+
+ __hlist_del(entry);
+ if (clear_pending)
+ entry->pprev = NULL;
+ entry->next = LIST_POISON2;
+}
+
+static int detach_if_pending(struct timer_list *timer, struct timer_base *base,
+ bool clear_pending)
+{
+ unsigned idx = timer_get_idx(timer);
+
+ if (!timer_pending(timer))
+ return 0;
+
+ if (hlist_is_singular_node(&timer->entry, base->vectors + idx))
+ __clear_bit(idx, base->pending_map);
+
+ detach_timer(timer, clear_pending);
+ return 1;
+}
+
+static inline struct timer_base *get_timer_cpu_base(u32 tflags, u32 cpu)
+{
+ struct timer_base *base = per_cpu_ptr(&timer_bases[BASE_STD], cpu);
+
+ /*
+ * If the timer is deferrable and NO_HZ_COMMON is set then we need
+ * to use the deferrable base.
+ */
+ if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && (tflags & TIMER_DEFERRABLE))
+ base = per_cpu_ptr(&timer_bases[BASE_DEF], cpu);
+ return base;
+}
+
+static inline struct timer_base *get_timer_this_cpu_base(u32 tflags)
+{
+ struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
+
+ /*
+ * If the timer is deferrable and NO_HZ_COMMON is set then we need
+ * to use the deferrable base.
+ */
+ if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && (tflags & TIMER_DEFERRABLE))
+ base = this_cpu_ptr(&timer_bases[BASE_DEF]);
+ return base;
+}
+
+static inline struct timer_base *get_timer_base(u32 tflags)
+{
+ return get_timer_cpu_base(tflags, tflags & TIMER_CPUMASK);
+}
+
+static inline struct timer_base *
+get_target_base(struct timer_base *base, unsigned tflags)
+{
+#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
+ if (static_branch_likely(&timers_migration_enabled) &&
+ !(tflags & TIMER_PINNED))
+ return get_timer_cpu_base(tflags, get_nohz_timer_target());
+#endif
+ return get_timer_this_cpu_base(tflags);
+}
+
+static inline void forward_timer_base(struct timer_base *base)
+{
+#ifdef CONFIG_NO_HZ_COMMON
+ unsigned long jnow;
+
+ /*
+ * We only forward the base when we are idle or have just come out of
+ * idle (must_forward_clk logic), and have a delta between base clock
+ * and jiffies. In the common case, run_timers will take care of it.
+ */
+ if (likely(!base->must_forward_clk))
+ return;
+
+ jnow = READ_ONCE(jiffies);
+ base->must_forward_clk = base->is_idle;
+ if ((long)(jnow - base->clk) < 2)
+ return;
+
+ /*
+ * If the next expiry value is > jiffies, then we fast forward to
+ * jiffies otherwise we forward to the next expiry value.
+ */
+ if (time_after(base->next_expiry, jnow))
+ base->clk = jnow;
+ else
+ base->clk = base->next_expiry;
+#endif
+}
+
+
+/*
+ * We are using hashed locking: Holding per_cpu(timer_bases[x]).lock means
+ * that all timers which are tied to this base are locked, and the base itself
+ * is locked too.
+ *
+ * So __run_timers/migrate_timers can safely modify all timers which could
+ * be found in the base->vectors array.
+ *
+ * When a timer is migrating then the TIMER_MIGRATING flag is set and we need
+ * to wait until the migration is done.
+ */
+static struct timer_base *lock_timer_base(struct timer_list *timer,
+ unsigned long *flags)
+ __acquires(timer->base->lock)
+{
+ for (;;) {
+ struct timer_base *base;
+ u32 tf;
+
+ /*
+ * We need to use READ_ONCE() here, otherwise the compiler
+ * might re-read @tf between the check for TIMER_MIGRATING
+ * and spin_lock().
+ */
+ tf = READ_ONCE(timer->flags);
+
+ if (!(tf & TIMER_MIGRATING)) {
+ base = get_timer_base(tf);
+ raw_spin_lock_irqsave(&base->lock, *flags);
+ if (timer->flags == tf)
+ return base;
+ raw_spin_unlock_irqrestore(&base->lock, *flags);
+ }
+ cpu_relax();
+ }
+}
+
+#define MOD_TIMER_PENDING_ONLY 0x01
+#define MOD_TIMER_REDUCE 0x02
+
+static inline int
+__mod_timer(struct timer_list *timer, unsigned long expires, unsigned int options)
+{
+ struct timer_base *base, *new_base;
+ unsigned int idx = UINT_MAX;
+ unsigned long clk = 0, flags;
+ int ret = 0;
+
+ BUG_ON(!timer->function);
+
+ /*
+ * This is a common optimization triggered by the networking code - if
+ * the timer is re-modified to have the same timeout or ends up in the
+ * same array bucket then just return:
+ */
+ if (timer_pending(timer)) {
+ /*
+ * The downside of this optimization is that it can result in
+ * larger granularity than you would get from adding a new
+ * timer with this expiry.
+ */
+ long diff = timer->expires - expires;
+
+ if (!diff)
+ return 1;
+ if (options & MOD_TIMER_REDUCE && diff <= 0)
+ return 1;
+
+ /*
+ * We lock timer base and calculate the bucket index right
+ * here. If the timer ends up in the same bucket, then we
+ * just update the expiry time and avoid the whole
+ * dequeue/enqueue dance.
+ */
+ base = lock_timer_base(timer, &flags);
+ forward_timer_base(base);
+
+ if (timer_pending(timer) && (options & MOD_TIMER_REDUCE) &&
+ time_before_eq(timer->expires, expires)) {
+ ret = 1;
+ goto out_unlock;
+ }
+
+ clk = base->clk;
+ idx = calc_wheel_index(expires, clk);
+
+ /*
+ * Retrieve and compare the array index of the pending
+ * timer. If it matches set the expiry to the new value so a
+ * subsequent call will exit in the expires check above.
+ */
+ if (idx == timer_get_idx(timer)) {
+ if (!(options & MOD_TIMER_REDUCE))
+ timer->expires = expires;
+ else if (time_after(timer->expires, expires))
+ timer->expires = expires;
+ ret = 1;
+ goto out_unlock;
+ }
+ } else {
+ base = lock_timer_base(timer, &flags);
+ forward_timer_base(base);
+ }
+
+ ret = detach_if_pending(timer, base, false);
+ if (!ret && (options & MOD_TIMER_PENDING_ONLY))
+ goto out_unlock;
+
+ new_base = get_target_base(base, timer->flags);
+
+ if (base != new_base) {
+ /*
+ * We are trying to schedule the timer on the new base.
+ * However we can't change timer's base while it is running,
+ * otherwise del_timer_sync() can't detect that the timer's
+ * handler yet has not finished. This also guarantees that the
+ * timer is serialized wrt itself.
+ */
+ if (likely(base->running_timer != timer)) {
+ /* See the comment in lock_timer_base() */
+ timer->flags |= TIMER_MIGRATING;
+
+ raw_spin_unlock(&base->lock);
+ base = new_base;
+ raw_spin_lock(&base->lock);
+ WRITE_ONCE(timer->flags,
+ (timer->flags & ~TIMER_BASEMASK) | base->cpu);
+ forward_timer_base(base);
+ }
+ }
+
+ debug_activate(timer, expires);
+
+ timer->expires = expires;
+ /*
+ * If 'idx' was calculated above and the base time did not advance
+ * between calculating 'idx' and possibly switching the base, only
+ * enqueue_timer() and trigger_dyntick_cpu() is required. Otherwise
+ * we need to (re)calculate the wheel index via
+ * internal_add_timer().
+ */
+ if (idx != UINT_MAX && clk == base->clk) {
+ enqueue_timer(base, timer, idx);
+ trigger_dyntick_cpu(base, timer);
+ } else {
+ internal_add_timer(base, timer);
+ }
+
+out_unlock:
+ raw_spin_unlock_irqrestore(&base->lock, flags);
+
+ return ret;
+}
+
+/**
+ * mod_timer_pending - modify a pending timer's timeout
+ * @timer: the pending timer to be modified
+ * @expires: new timeout in jiffies
+ *
+ * mod_timer_pending() is the same for pending timers as mod_timer(),
+ * but will not re-activate and modify already deleted timers.
+ *
+ * It is useful for unserialized use of timers.
+ */
+int mod_timer_pending(struct timer_list *timer, unsigned long expires)
+{
+ return __mod_timer(timer, expires, MOD_TIMER_PENDING_ONLY);
+}
+EXPORT_SYMBOL(mod_timer_pending);
+
+/**
+ * mod_timer - modify a timer's timeout
+ * @timer: the timer to be modified
+ * @expires: new timeout in jiffies
+ *
+ * mod_timer() is a more efficient way to update the expire field of an
+ * active timer (if the timer is inactive it will be activated)
+ *
+ * mod_timer(timer, expires) is equivalent to:
+ *
+ * del_timer(timer); timer->expires = expires; add_timer(timer);
+ *
+ * Note that if there are multiple unserialized concurrent users of the
+ * same timer, then mod_timer() is the only safe way to modify the timeout,
+ * since add_timer() cannot modify an already running timer.
+ *
+ * The function returns whether it has modified a pending timer or not.
+ * (ie. mod_timer() of an inactive timer returns 0, mod_timer() of an
+ * active timer returns 1.)
+ */
+int mod_timer(struct timer_list *timer, unsigned long expires)
+{
+ return __mod_timer(timer, expires, 0);
+}
+EXPORT_SYMBOL(mod_timer);
+
+/**
+ * timer_reduce - Modify a timer's timeout if it would reduce the timeout
+ * @timer: The timer to be modified
+ * @expires: New timeout in jiffies
+ *
+ * timer_reduce() is very similar to mod_timer(), except that it will only
+ * modify a running timer if that would reduce the expiration time (it will
+ * start a timer that isn't running).
+ */
+int timer_reduce(struct timer_list *timer, unsigned long expires)
+{
+ return __mod_timer(timer, expires, MOD_TIMER_REDUCE);
+}
+EXPORT_SYMBOL(timer_reduce);
+
+/**
+ * add_timer - start a timer
+ * @timer: the timer to be added
+ *
+ * The kernel will do a ->function(@timer) callback from the
+ * timer interrupt at the ->expires point in the future. The
+ * current time is 'jiffies'.
+ *
+ * The timer's ->expires, ->function fields must be set prior calling this
+ * function.
+ *
+ * Timers with an ->expires field in the past will be executed in the next
+ * timer tick.
+ */
+void add_timer(struct timer_list *timer)
+{
+ BUG_ON(timer_pending(timer));
+ mod_timer(timer, timer->expires);
+}
+EXPORT_SYMBOL(add_timer);
+
+/**
+ * add_timer_on - start a timer on a particular CPU
+ * @timer: the timer to be added
+ * @cpu: the CPU to start it on
+ *
+ * This is not very scalable on SMP. Double adds are not possible.
+ */
+void add_timer_on(struct timer_list *timer, int cpu)
+{
+ struct timer_base *new_base, *base;
+ unsigned long flags;
+
+ BUG_ON(timer_pending(timer) || !timer->function);
+
+ new_base = get_timer_cpu_base(timer->flags, cpu);
+
+ /*
+ * If @timer was on a different CPU, it should be migrated with the
+ * old base locked to prevent other operations proceeding with the
+ * wrong base locked. See lock_timer_base().
+ */
+ base = lock_timer_base(timer, &flags);
+ if (base != new_base) {
+ timer->flags |= TIMER_MIGRATING;
+
+ raw_spin_unlock(&base->lock);
+ base = new_base;
+ raw_spin_lock(&base->lock);
+ WRITE_ONCE(timer->flags,
+ (timer->flags & ~TIMER_BASEMASK) | cpu);
+ }
+ forward_timer_base(base);
+
+ debug_activate(timer, timer->expires);
+ internal_add_timer(base, timer);
+ raw_spin_unlock_irqrestore(&base->lock, flags);
+}
+EXPORT_SYMBOL_GPL(add_timer_on);
+
+/**
+ * del_timer - deactivate a timer.
+ * @timer: the timer to be deactivated
+ *
+ * del_timer() deactivates a timer - this works on both active and inactive
+ * timers.
+ *
+ * The function returns whether it has deactivated a pending timer or not.
+ * (ie. del_timer() of an inactive timer returns 0, del_timer() of an
+ * active timer returns 1.)
+ */
+int del_timer(struct timer_list *timer)
+{
+ struct timer_base *base;
+ unsigned long flags;
+ int ret = 0;
+
+ debug_assert_init(timer);
+
+ if (timer_pending(timer)) {
+ base = lock_timer_base(timer, &flags);
+ ret = detach_if_pending(timer, base, true);
+ raw_spin_unlock_irqrestore(&base->lock, flags);
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL(del_timer);
+
+/**
+ * try_to_del_timer_sync - Try to deactivate a timer
+ * @timer: timer to delete
+ *
+ * This function tries to deactivate a timer. Upon successful (ret >= 0)
+ * exit the timer is not queued and the handler is not running on any CPU.
+ */
+int try_to_del_timer_sync(struct timer_list *timer)
+{
+ struct timer_base *base;
+ unsigned long flags;
+ int ret = -1;
+
+ debug_assert_init(timer);
+
+ base = lock_timer_base(timer, &flags);
+
+ if (base->running_timer != timer)
+ ret = detach_if_pending(timer, base, true);
+
+ raw_spin_unlock_irqrestore(&base->lock, flags);
+
+ return ret;
+}
+EXPORT_SYMBOL(try_to_del_timer_sync);
+
+#ifdef CONFIG_SMP
+/**
+ * del_timer_sync - deactivate a timer and wait for the handler to finish.
+ * @timer: the timer to be deactivated
+ *
+ * This function only differs from del_timer() on SMP: besides deactivating
+ * the timer it also makes sure the handler has finished executing on other
+ * CPUs.
+ *
+ * Synchronization rules: Callers must prevent restarting of the timer,
+ * otherwise this function is meaningless. It must not be called from
+ * interrupt contexts unless the timer is an irqsafe one. The caller must
+ * not hold locks which would prevent completion of the timer's
+ * handler. The timer's handler must not call add_timer_on(). Upon exit the
+ * timer is not queued and the handler is not running on any CPU.
+ *
+ * Note: For !irqsafe timers, you must not hold locks that are held in
+ * interrupt context while calling this function. Even if the lock has
+ * nothing to do with the timer in question. Here's why::
+ *
+ * CPU0 CPU1
+ * ---- ----
+ * <SOFTIRQ>
+ * call_timer_fn();
+ * base->running_timer = mytimer;
+ * spin_lock_irq(somelock);
+ * <IRQ>
+ * spin_lock(somelock);
+ * del_timer_sync(mytimer);
+ * while (base->running_timer == mytimer);
+ *
+ * Now del_timer_sync() will never return and never release somelock.
+ * The interrupt on the other CPU is waiting to grab somelock but
+ * it has interrupted the softirq that CPU0 is waiting to finish.
+ *
+ * The function returns whether it has deactivated a pending timer or not.
+ */
+int del_timer_sync(struct timer_list *timer)
+{
+#ifdef CONFIG_LOCKDEP
+ unsigned long flags;
+
+ /*
+ * If lockdep gives a backtrace here, please reference
+ * the synchronization rules above.
+ */
+ local_irq_save(flags);
+ lock_map_acquire(&timer->lockdep_map);
+ lock_map_release(&timer->lockdep_map);
+ local_irq_restore(flags);
+#endif
+ /*
+ * don't use it in hardirq context, because it
+ * could lead to deadlock.
+ */
+ WARN_ON(in_irq() && !(timer->flags & TIMER_IRQSAFE));
+ for (;;) {
+ int ret = try_to_del_timer_sync(timer);
+ if (ret >= 0)
+ return ret;
+ cpu_relax();
+ }
+}
+EXPORT_SYMBOL(del_timer_sync);
+#endif
+
+static void call_timer_fn(struct timer_list *timer, void (*fn)(struct timer_list *))
+{
+ int count = preempt_count();
+
+#ifdef CONFIG_LOCKDEP
+ /*
+ * It is permissible to free the timer from inside the
+ * function that is called from it, this we need to take into
+ * account for lockdep too. To avoid bogus "held lock freed"
+ * warnings as well as problems when looking into
+ * timer->lockdep_map, make a copy and use that here.
+ */
+ struct lockdep_map lockdep_map;
+
+ lockdep_copy_map(&lockdep_map, &timer->lockdep_map);
+#endif
+ /*
+ * Couple the lock chain with the lock chain at
+ * del_timer_sync() by acquiring the lock_map around the fn()
+ * call here and in del_timer_sync().
+ */
+ lock_map_acquire(&lockdep_map);
+
+ trace_timer_expire_entry(timer);
+ fn(timer);
+ trace_timer_expire_exit(timer);
+
+ lock_map_release(&lockdep_map);
+
+ if (count != preempt_count()) {
+ WARN_ONCE(1, "timer: %pF preempt leak: %08x -> %08x\n",
+ fn, count, preempt_count());
+ /*
+ * Restore the preempt count. That gives us a decent
+ * chance to survive and extract information. If the
+ * callback kept a lock held, bad luck, but not worse
+ * than the BUG() we had.
+ */
+ preempt_count_set(count);
+ }
+}
+
+static void expire_timers(struct timer_base *base, struct hlist_head *head)
+{
+ while (!hlist_empty(head)) {
+ struct timer_list *timer;
+ void (*fn)(struct timer_list *);
+
+ timer = hlist_entry(head->first, struct timer_list, entry);
+
+ base->running_timer = timer;
+ detach_timer(timer, true);
+
+ fn = timer->function;
+
+ if (timer->flags & TIMER_IRQSAFE) {
+ raw_spin_unlock(&base->lock);
+ call_timer_fn(timer, fn);
+ raw_spin_lock(&base->lock);
+ } else {
+ raw_spin_unlock_irq(&base->lock);
+ call_timer_fn(timer, fn);
+ raw_spin_lock_irq(&base->lock);
+ }
+ }
+}
+
+static int __collect_expired_timers(struct timer_base *base,
+ struct hlist_head *heads)
+{
+ unsigned long clk = base->clk;
+ struct hlist_head *vec;
+ int i, levels = 0;
+ unsigned int idx;
+
+ for (i = 0; i < LVL_DEPTH; i++) {
+ idx = (clk & LVL_MASK) + i * LVL_SIZE;
+
+ if (__test_and_clear_bit(idx, base->pending_map)) {
+ vec = base->vectors + idx;
+ hlist_move_list(vec, heads++);
+ levels++;
+ }
+ /* Is it time to look at the next level? */
+ if (clk & LVL_CLK_MASK)
+ break;
+ /* Shift clock for the next level granularity */
+ clk >>= LVL_CLK_SHIFT;
+ }
+ return levels;
+}
+
+#ifdef CONFIG_NO_HZ_COMMON
+/*
+ * Find the next pending bucket of a level. Search from level start (@offset)
+ * + @clk upwards and if nothing there, search from start of the level
+ * (@offset) up to @offset + clk.
+ */
+static int next_pending_bucket(struct timer_base *base, unsigned offset,
+ unsigned clk)
+{
+ unsigned pos, start = offset + clk;
+ unsigned end = offset + LVL_SIZE;
+
+ pos = find_next_bit(base->pending_map, end, start);
+ if (pos < end)
+ return pos - start;
+
+ pos = find_next_bit(base->pending_map, start, offset);
+ return pos < start ? pos + LVL_SIZE - start : -1;
+}
+
+/*
+ * Search the first expiring timer in the various clock levels. Caller must
+ * hold base->lock.
+ */
+static unsigned long __next_timer_interrupt(struct timer_base *base)
+{
+ unsigned long clk, next, adj;
+ unsigned lvl, offset = 0;
+
+ next = base->clk + NEXT_TIMER_MAX_DELTA;
+ clk = base->clk;
+ for (lvl = 0; lvl < LVL_DEPTH; lvl++, offset += LVL_SIZE) {
+ int pos = next_pending_bucket(base, offset, clk & LVL_MASK);
+
+ if (pos >= 0) {
+ unsigned long tmp = clk + (unsigned long) pos;
+
+ tmp <<= LVL_SHIFT(lvl);
+ if (time_before(tmp, next))
+ next = tmp;
+ }
+ /*
+ * Clock for the next level. If the current level clock lower
+ * bits are zero, we look at the next level as is. If not we
+ * need to advance it by one because that's going to be the
+ * next expiring bucket in that level. base->clk is the next
+ * expiring jiffie. So in case of:
+ *
+ * LVL5 LVL4 LVL3 LVL2 LVL1 LVL0
+ * 0 0 0 0 0 0
+ *
+ * we have to look at all levels @index 0. With
+ *
+ * LVL5 LVL4 LVL3 LVL2 LVL1 LVL0
+ * 0 0 0 0 0 2
+ *
+ * LVL0 has the next expiring bucket @index 2. The upper
+ * levels have the next expiring bucket @index 1.
+ *
+ * In case that the propagation wraps the next level the same
+ * rules apply:
+ *
+ * LVL5 LVL4 LVL3 LVL2 LVL1 LVL0
+ * 0 0 0 0 F 2
+ *
+ * So after looking at LVL0 we get:
+ *
+ * LVL5 LVL4 LVL3 LVL2 LVL1
+ * 0 0 0 1 0
+ *
+ * So no propagation from LVL1 to LVL2 because that happened
+ * with the add already, but then we need to propagate further
+ * from LVL2 to LVL3.
+ *
+ * So the simple check whether the lower bits of the current
+ * level are 0 or not is sufficient for all cases.
+ */
+ adj = clk & LVL_CLK_MASK ? 1 : 0;
+ clk >>= LVL_CLK_SHIFT;
+ clk += adj;
+ }
+ return next;
+}
+
+/*
+ * Check, if the next hrtimer event is before the next timer wheel
+ * event:
+ */
+static u64 cmp_next_hrtimer_event(u64 basem, u64 expires)
+{
+ u64 nextevt = hrtimer_get_next_event();
+
+ /*
+ * If high resolution timers are enabled
+ * hrtimer_get_next_event() returns KTIME_MAX.
+ */
+ if (expires <= nextevt)
+ return expires;
+
+ /*
+ * If the next timer is already expired, return the tick base
+ * time so the tick is fired immediately.
+ */
+ if (nextevt <= basem)
+ return basem;
+
+ /*
+ * Round up to the next jiffie. High resolution timers are
+ * off, so the hrtimers are expired in the tick and we need to
+ * make sure that this tick really expires the timer to avoid
+ * a ping pong of the nohz stop code.
+ *
+ * Use DIV_ROUND_UP_ULL to prevent gcc calling __divdi3
+ */
+ return DIV_ROUND_UP_ULL(nextevt, TICK_NSEC) * TICK_NSEC;
+}
+
+/**
+ * get_next_timer_interrupt - return the time (clock mono) of the next timer
+ * @basej: base time jiffies
+ * @basem: base time clock monotonic
+ *
+ * Returns the tick aligned clock monotonic time of the next pending
+ * timer or KTIME_MAX if no timer is pending.
+ */
+u64 get_next_timer_interrupt(unsigned long basej, u64 basem)
+{
+ struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
+ u64 expires = KTIME_MAX;
+ unsigned long nextevt;
+ bool is_max_delta;
+
+ /*
+ * Pretend that there is no timer pending if the cpu is offline.
+ * Possible pending timers will be migrated later to an active cpu.
+ */
+ if (cpu_is_offline(smp_processor_id()))
+ return expires;
+
+ raw_spin_lock(&base->lock);
+ nextevt = __next_timer_interrupt(base);
+ is_max_delta = (nextevt == base->clk + NEXT_TIMER_MAX_DELTA);
+ base->next_expiry = nextevt;
+ /*
+ * We have a fresh next event. Check whether we can forward the
+ * base. We can only do that when @basej is past base->clk
+ * otherwise we might rewind base->clk.
+ */
+ if (time_after(basej, base->clk)) {
+ if (time_after(nextevt, basej))
+ base->clk = basej;
+ else if (time_after(nextevt, base->clk))
+ base->clk = nextevt;
+ }
+
+ if (time_before_eq(nextevt, basej)) {
+ expires = basem;
+ base->is_idle = false;
+ } else {
+ if (!is_max_delta)
+ expires = basem + (u64)(nextevt - basej) * TICK_NSEC;
+ /*
+ * If we expect to sleep more than a tick, mark the base idle.
+ * Also the tick is stopped so any added timer must forward
+ * the base clk itself to keep granularity small. This idle
+ * logic is only maintained for the BASE_STD base, deferrable
+ * timers may still see large granularity skew (by design).
+ */
+ if ((expires - basem) > TICK_NSEC) {
+ base->must_forward_clk = true;
+ base->is_idle = true;
+ }
+ }
+ raw_spin_unlock(&base->lock);
+
+ return cmp_next_hrtimer_event(basem, expires);
+}
+
+/**
+ * timer_clear_idle - Clear the idle state of the timer base
+ *
+ * Called with interrupts disabled
+ */
+void timer_clear_idle(void)
+{
+ struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
+
+ /*
+ * We do this unlocked. The worst outcome is a remote enqueue sending
+ * a pointless IPI, but taking the lock would just make the window for
+ * sending the IPI a few instructions smaller for the cost of taking
+ * the lock in the exit from idle path.
+ */
+ base->is_idle = false;
+}
+
+static int collect_expired_timers(struct timer_base *base,
+ struct hlist_head *heads)
+{
+ /*
+ * NOHZ optimization. After a long idle sleep we need to forward the
+ * base to current jiffies. Avoid a loop by searching the bitfield for
+ * the next expiring timer.
+ */
+ if ((long)(jiffies - base->clk) > 2) {
+ unsigned long next = __next_timer_interrupt(base);
+
+ /*
+ * If the next timer is ahead of time forward to current
+ * jiffies, otherwise forward to the next expiry time:
+ */
+ if (time_after(next, jiffies)) {
+ /*
+ * The call site will increment base->clk and then
+ * terminate the expiry loop immediately.
+ */
+ base->clk = jiffies;
+ return 0;
+ }
+ base->clk = next;
+ }
+ return __collect_expired_timers(base, heads);
+}
+#else
+static inline int collect_expired_timers(struct timer_base *base,
+ struct hlist_head *heads)
+{
+ return __collect_expired_timers(base, heads);
+}
+#endif
+
+/*
+ * Called from the timer interrupt handler to charge one tick to the current
+ * process. user_tick is 1 if the tick is user time, 0 for system.
+ */
+void update_process_times(int user_tick)
+{
+ struct task_struct *p = current;
+
+ /* Note: this timer irq context must be accounted for as well. */
+ account_process_tick(p, user_tick);
+ run_local_timers();
+ rcu_check_callbacks(user_tick);
+#ifdef CONFIG_IRQ_WORK
+ if (in_irq())
+ irq_work_tick();
+#endif
+ scheduler_tick();
+ if (IS_ENABLED(CONFIG_POSIX_TIMERS))
+ run_posix_cpu_timers(p);
+}
+
+/**
+ * __run_timers - run all expired timers (if any) on this CPU.
+ * @base: the timer vector to be processed.
+ */
+static inline void __run_timers(struct timer_base *base)
+{
+ struct hlist_head heads[LVL_DEPTH];
+ int levels;
+
+ if (!time_after_eq(jiffies, base->clk))
+ return;
+
+ raw_spin_lock_irq(&base->lock);
+
+ /*
+ * timer_base::must_forward_clk must be cleared before running
+ * timers so that any timer functions that call mod_timer() will
+ * not try to forward the base. Idle tracking / clock forwarding
+ * logic is only used with BASE_STD timers.
+ *
+ * The must_forward_clk flag is cleared unconditionally also for
+ * the deferrable base. The deferrable base is not affected by idle
+ * tracking and never forwarded, so clearing the flag is a NOOP.
+ *
+ * The fact that the deferrable base is never forwarded can cause
+ * large variations in granularity for deferrable timers, but they
+ * can be deferred for long periods due to idle anyway.
+ */
+ base->must_forward_clk = false;
+
+ while (time_after_eq(jiffies, base->clk)) {
+
+ levels = collect_expired_timers(base, heads);
+ base->clk++;
+
+ while (levels--)
+ expire_timers(base, heads + levels);
+ }
+ base->running_timer = NULL;
+ raw_spin_unlock_irq(&base->lock);
+}
+
+/*
+ * This function runs timers and the timer-tq in bottom half context.
+ */
+static __latent_entropy void run_timer_softirq(struct softirq_action *h)
+{
+ struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
+
+ __run_timers(base);
+ if (IS_ENABLED(CONFIG_NO_HZ_COMMON))
+ __run_timers(this_cpu_ptr(&timer_bases[BASE_DEF]));
+}
+
+/*
+ * Called by the local, per-CPU timer interrupt on SMP.
+ */
+void run_local_timers(void)
+{
+ struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
+
+ hrtimer_run_queues();
+ /* Raise the softirq only if required. */
+ if (time_before(jiffies, base->clk)) {
+ if (!IS_ENABLED(CONFIG_NO_HZ_COMMON))
+ return;
+ /* CPU is awake, so check the deferrable base. */
+ base++;
+ if (time_before(jiffies, base->clk))
+ return;
+ }
+ raise_softirq(TIMER_SOFTIRQ);
+}
+
+/*
+ * Since schedule_timeout()'s timer is defined on the stack, it must store
+ * the target task on the stack as well.
+ */
+struct process_timer {
+ struct timer_list timer;
+ struct task_struct *task;
+};
+
+static void process_timeout(struct timer_list *t)
+{
+ struct process_timer *timeout = from_timer(timeout, t, timer);
+
+ wake_up_process(timeout->task);
+}
+
+/**
+ * schedule_timeout - sleep until timeout
+ * @timeout: timeout value in jiffies
+ *
+ * Make the current task sleep until @timeout jiffies have
+ * elapsed. The routine will return immediately unless
+ * the current task state has been set (see set_current_state()).
+ *
+ * You can set the task state as follows -
+ *
+ * %TASK_UNINTERRUPTIBLE - at least @timeout jiffies are guaranteed to
+ * pass before the routine returns unless the current task is explicitly
+ * woken up, (e.g. by wake_up_process())".
+ *
+ * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
+ * delivered to the current task or the current task is explicitly woken
+ * up.
+ *
+ * The current task state is guaranteed to be TASK_RUNNING when this
+ * routine returns.
+ *
+ * Specifying a @timeout value of %MAX_SCHEDULE_TIMEOUT will schedule
+ * the CPU away without a bound on the timeout. In this case the return
+ * value will be %MAX_SCHEDULE_TIMEOUT.
+ *
+ * Returns 0 when the timer has expired otherwise the remaining time in
+ * jiffies will be returned. In all cases the return value is guaranteed
+ * to be non-negative.
+ */
+signed long __sched schedule_timeout(signed long timeout)
+{
+ struct process_timer timer;
+ unsigned long expire;
+
+ switch (timeout)
+ {
+ case MAX_SCHEDULE_TIMEOUT:
+ /*
+ * These two special cases are useful to be comfortable
+ * in the caller. Nothing more. We could take
+ * MAX_SCHEDULE_TIMEOUT from one of the negative value
+ * but I' d like to return a valid offset (>=0) to allow
+ * the caller to do everything it want with the retval.
+ */
+ schedule();
+ goto out;
+ default:
+ /*
+ * Another bit of PARANOID. Note that the retval will be
+ * 0 since no piece of kernel is supposed to do a check
+ * for a negative retval of schedule_timeout() (since it
+ * should never happens anyway). You just have the printk()
+ * that will tell you if something is gone wrong and where.
+ */
+ if (timeout < 0) {
+ printk(KERN_ERR "schedule_timeout: wrong timeout "
+ "value %lx\n", timeout);
+ dump_stack();
+ current->state = TASK_RUNNING;
+ goto out;
+ }
+ }
+
+ expire = timeout + jiffies;
+
+ timer.task = current;
+ timer_setup_on_stack(&timer.timer, process_timeout, 0);
+ __mod_timer(&timer.timer, expire, 0);
+ schedule();
+ del_singleshot_timer_sync(&timer.timer);
+
+ /* Remove the timer from the object tracker */
+ destroy_timer_on_stack(&timer.timer);
+
+ timeout = expire - jiffies;
+
+ out:
+ return timeout < 0 ? 0 : timeout;
+}
+EXPORT_SYMBOL(schedule_timeout);
+
+/*
+ * We can use __set_current_state() here because schedule_timeout() calls
+ * schedule() unconditionally.
+ */
+signed long __sched schedule_timeout_interruptible(signed long timeout)
+{
+ __set_current_state(TASK_INTERRUPTIBLE);
+ return schedule_timeout(timeout);
+}
+EXPORT_SYMBOL(schedule_timeout_interruptible);
+
+signed long __sched schedule_timeout_killable(signed long timeout)
+{
+ __set_current_state(TASK_KILLABLE);
+ return schedule_timeout(timeout);
+}
+EXPORT_SYMBOL(schedule_timeout_killable);
+
+signed long __sched schedule_timeout_uninterruptible(signed long timeout)
+{
+ __set_current_state(TASK_UNINTERRUPTIBLE);
+ return schedule_timeout(timeout);
+}
+EXPORT_SYMBOL(schedule_timeout_uninterruptible);
+
+/*
+ * Like schedule_timeout_uninterruptible(), except this task will not contribute
+ * to load average.
+ */
+signed long __sched schedule_timeout_idle(signed long timeout)
+{
+ __set_current_state(TASK_IDLE);
+ return schedule_timeout(timeout);
+}
+EXPORT_SYMBOL(schedule_timeout_idle);
+
+#ifdef CONFIG_HOTPLUG_CPU
+static void migrate_timer_list(struct timer_base *new_base, struct hlist_head *head)
+{
+ struct timer_list *timer;
+ int cpu = new_base->cpu;
+
+ while (!hlist_empty(head)) {
+ timer = hlist_entry(head->first, struct timer_list, entry);
+ detach_timer(timer, false);
+ timer->flags = (timer->flags & ~TIMER_BASEMASK) | cpu;
+ internal_add_timer(new_base, timer);
+ }
+}
+
+int timers_prepare_cpu(unsigned int cpu)
+{
+ struct timer_base *base;
+ int b;
+
+ for (b = 0; b < NR_BASES; b++) {
+ base = per_cpu_ptr(&timer_bases[b], cpu);
+ base->clk = jiffies;
+ base->next_expiry = base->clk + NEXT_TIMER_MAX_DELTA;
+ base->is_idle = false;
+ base->must_forward_clk = true;
+ }
+ return 0;
+}
+
+int timers_dead_cpu(unsigned int cpu)
+{
+ struct timer_base *old_base;
+ struct timer_base *new_base;
+ int b, i;
+
+ BUG_ON(cpu_online(cpu));
+
+ for (b = 0; b < NR_BASES; b++) {
+ old_base = per_cpu_ptr(&timer_bases[b], cpu);
+ new_base = get_cpu_ptr(&timer_bases[b]);
+ /*
+ * The caller is globally serialized and nobody else
+ * takes two locks at once, deadlock is not possible.
+ */
+ raw_spin_lock_irq(&new_base->lock);
+ raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
+
+ /*
+ * The current CPUs base clock might be stale. Update it
+ * before moving the timers over.
+ */
+ forward_timer_base(new_base);
+
+ BUG_ON(old_base->running_timer);
+
+ for (i = 0; i < WHEEL_SIZE; i++)
+ migrate_timer_list(new_base, old_base->vectors + i);
+
+ raw_spin_unlock(&old_base->lock);
+ raw_spin_unlock_irq(&new_base->lock);
+ put_cpu_ptr(&timer_bases);
+ }
+ return 0;
+}
+
+#endif /* CONFIG_HOTPLUG_CPU */
+
+static void __init init_timer_cpu(int cpu)
+{
+ struct timer_base *base;
+ int i;
+
+ for (i = 0; i < NR_BASES; i++) {
+ base = per_cpu_ptr(&timer_bases[i], cpu);
+ base->cpu = cpu;
+ raw_spin_lock_init(&base->lock);
+ base->clk = jiffies;
+ }
+}
+
+static void __init init_timer_cpus(void)
+{
+ int cpu;
+
+ for_each_possible_cpu(cpu)
+ init_timer_cpu(cpu);
+}
+
+void __init init_timers(void)
+{
+ init_timer_cpus();
+ open_softirq(TIMER_SOFTIRQ, run_timer_softirq);
+}
+
+/**
+ * msleep - sleep safely even with waitqueue interruptions
+ * @msecs: Time in milliseconds to sleep for
+ */
+void msleep(unsigned int msecs)
+{
+ unsigned long timeout = msecs_to_jiffies(msecs) + 1;
+
+ while (timeout)
+ timeout = schedule_timeout_uninterruptible(timeout);
+}
+
+EXPORT_SYMBOL(msleep);
+
+/**
+ * msleep_interruptible - sleep waiting for signals
+ * @msecs: Time in milliseconds to sleep for
+ */
+unsigned long msleep_interruptible(unsigned int msecs)
+{
+ unsigned long timeout = msecs_to_jiffies(msecs) + 1;
+
+ while (timeout && !signal_pending(current))
+ timeout = schedule_timeout_interruptible(timeout);
+ return jiffies_to_msecs(timeout);
+}
+
+EXPORT_SYMBOL(msleep_interruptible);
+
+/**
+ * usleep_range - Sleep for an approximate time
+ * @min: Minimum time in usecs to sleep
+ * @max: Maximum time in usecs to sleep
+ *
+ * In non-atomic context where the exact wakeup time is flexible, use
+ * usleep_range() instead of udelay(). The sleep improves responsiveness
+ * by avoiding the CPU-hogging busy-wait of udelay(), and the range reduces
+ * power usage by allowing hrtimers to take advantage of an already-
+ * scheduled interrupt instead of scheduling a new one just for this sleep.
+ */
+void __sched usleep_range(unsigned long min, unsigned long max)
+{
+ ktime_t exp = ktime_add_us(ktime_get(), min);
+ u64 delta = (u64)(max - min) * NSEC_PER_USEC;
+
+ for (;;) {
+ __set_current_state(TASK_UNINTERRUPTIBLE);
+ /* Do not return before the requested sleep time has elapsed */
+ if (!schedule_hrtimeout_range(&exp, delta, HRTIMER_MODE_ABS))
+ break;
+ }
+}
+EXPORT_SYMBOL(usleep_range);