[PATCH 19/37] posix-timers: Convert internals to use nsecs

[Frederic Weisbecker <fweisbec@gmail.com>]

Use the new nsec based cputime accessors as part of the whole cputime
conversion from cputime_t to nsecs.

Also convert posix-cpu-timers to use nsec based internal counters to
simplify it.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
---
 include/linux/posix-timers.h   |  12 +--
 include/linux/sched.h          |   6 +-
 kernel/fork.c                  |   2 +-
 kernel/sched/cputime.c         |   6 +-
 kernel/sched/stats.h           |   4 +-
 kernel/time/itimer.c           |   6 +-
 kernel/time/posix-cpu-timers.c | 210 +++++++++++++++++------------------------
 7 files changed, 100 insertions(+), 146 deletions(-)

diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
index 62d44c1..890de52 100644
--- a/include/linux/posix-timers.h
+++ b/include/linux/posix-timers.h
@@ -8,19 +8,9 @@
 #include <linux/alarmtimer.h>
 
 
-static inline unsigned long long cputime_to_expires(cputime_t expires)
-{
-	return (__force unsigned long long)expires;
-}
-
-static inline cputime_t expires_to_cputime(unsigned long long expires)
-{
-	return (__force cputime_t)expires;
-}
-
 struct cpu_timer_list {
 	struct list_head entry;
-	unsigned long long expires, incr;
+	u64 expires, incr;
 	struct task_struct *task;
 	int firing;
 };
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 7fcbffa..2768f94 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -755,7 +755,7 @@ struct signal_struct {
 	struct thread_group_cputimer cputimer;
 
 	/* Earliest-expiration cache. */
-	struct task_cputime_t cputime_expires;
+	struct task_cputime cputime_expires;
 
 #ifdef CONFIG_NO_HZ_FULL
 	atomic_t tick_dep_mask;
@@ -1689,7 +1689,7 @@ struct task_struct {
 /* mm fault and swap info: this can arguably be seen as either mm-specific or thread-specific */
 	unsigned long min_flt, maj_flt;
 
-	struct task_cputime_t cputime_expires;
+	struct task_cputime cputime_expires;
 	struct list_head cpu_timers[3];
 
 /* process credentials */
@@ -3528,7 +3528,7 @@ static __always_inline bool need_resched(void)
  * Thread group CPU time accounting.
  */
 void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times);
-void thread_group_cputimer(struct task_struct *tsk, struct task_cputime_t *times);
+void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times);
 
 static inline void thread_group_cputime_t(struct task_struct *tsk,
 					  struct task_cputime_t *cputime)
diff --git a/kernel/fork.c b/kernel/fork.c
index 11c5c8a..09992ff 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1313,7 +1313,7 @@ static void posix_cpu_timers_init_group(struct signal_struct *sig)
 
 	cpu_limit = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
 	if (cpu_limit != RLIM_INFINITY) {
-		sig->cputime_expires.prof_exp = secs_to_cputime(cpu_limit);
+		sig->cputime_expires.prof_exp = cpu_limit * NSEC_PER_SEC;
 		sig->cputimer.running = true;
 	}
 
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index bee6c97..f7b9624 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -122,7 +122,7 @@ void account_user_time(struct task_struct *p, cputime_t cputime)
 
 	/* Add user time to process. */
 	p->utime += cputime_to_nsecs(cputime);
-	account_group_user_time(p, cputime);
+	account_group_user_time(p, cputime_to_nsecs(cputime));
 
 	index = (task_nice(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;
 
@@ -144,7 +144,7 @@ void account_guest_time(struct task_struct *p, cputime_t cputime)
 
 	/* Add guest time to process. */
 	p->utime += cputime_to_nsecs(cputime);
-	account_group_user_time(p, cputime);
+	account_group_user_time(p, cputime_to_nsecs(cputime));
 	p->gtime += cputime_to_nsecs(cputime);
 
 	/* Add guest time to cpustat. */
@@ -168,7 +168,7 @@ void account_system_index_time(struct task_struct *p,
 {
 	/* Add system time to process. */
 	p->stime += cputime_to_nsecs(cputime);
-	account_group_system_time(p, cputime);
+	account_group_system_time(p, cputime_to_nsecs(cputime));
 
 	/* Add system time to cpustat. */
 	task_group_account_field(p, index, cputime_to_nsecs(cputime));
diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h
index 34659a8..9788478 100644
--- a/kernel/sched/stats.h
+++ b/kernel/sched/stats.h
@@ -216,7 +216,7 @@ static inline bool cputimer_running(struct task_struct *tsk)
  * running CPU and update the utime field there.
  */
 static inline void account_group_user_time(struct task_struct *tsk,
-					   cputime_t cputime)
+					   u64 cputime)
 {
 	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
 
@@ -237,7 +237,7 @@ static inline void account_group_user_time(struct task_struct *tsk,
  * running CPU and update the stime field there.
  */
 static inline void account_group_system_time(struct task_struct *tsk,
-					     cputime_t cputime)
+					     u64 cputime)
 {
 	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
 
diff --git a/kernel/time/itimer.c b/kernel/time/itimer.c
index f2d5097..bb01ff4 100644
--- a/kernel/time/itimer.c
+++ b/kernel/time/itimer.c
@@ -53,15 +53,15 @@ static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
 	cval = it->expires;
 	cinterval = it->incr;
 	if (cval) {
-		struct task_cputime_t cputime;
+		struct task_cputime cputime;
 		cputime_t t;
 
 		thread_group_cputimer(tsk, &cputime);
 		if (clock_id == CPUCLOCK_PROF)
-			t = cputime.utime + cputime.stime;
+			t = nsecs_to_cputime(cputime.utime + cputime.stime);
 		else
 			/* CPUCLOCK_VIRT */
-			t = cputime.utime;
+			t = nsecs_to_cputime(cputime.utime);
 
 		if (cval < t)
 			/* about to fire */
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index 8349e02..45be3ce 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -50,39 +50,14 @@ static int check_clock(const clockid_t which_clock)
 	return error;
 }
 
-static inline unsigned long long
-timespec_to_sample(const clockid_t which_clock, const struct timespec *tp)
-{
-	unsigned long long ret;
-
-	ret = 0;		/* high half always zero when .cpu used */
-	if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
-		ret = (unsigned long long)tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
-	} else {
-		ret = cputime_to_expires(timespec_to_cputime(tp));
-	}
-	return ret;
-}
-
-static void sample_to_timespec(const clockid_t which_clock,
-			       unsigned long long expires,
-			       struct timespec *tp)
-{
-	if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED)
-		*tp = ns_to_timespec(expires);
-	else
-		cputime_to_timespec((__force cputime_t)expires, tp);
-}
-
 /*
  * Update expiry time from increment, and increase overrun count,
  * given the current clock sample.
  */
-static void bump_cpu_timer(struct k_itimer *timer,
-			   unsigned long long now)
+static void bump_cpu_timer(struct k_itimer *timer, u64 now)
 {
 	int i;
-	unsigned long long delta, incr;
+	u64 delta, incr;
 
 	if (timer->it.cpu.incr == 0)
 		return;
@@ -115,28 +90,28 @@ static void bump_cpu_timer(struct k_itimer *timer,
  * Checks @cputime to see if all fields are zero.  Returns true if all fields
  * are zero, false if any field is nonzero.
  */
-static inline int task_cputime_zero(const struct task_cputime_t *cputime)
+static inline int task_cputime_zero(const struct task_cputime *cputime)
 {
 	if (!cputime->utime && !cputime->stime && !cputime->sum_exec_runtime)
 		return 1;
 	return 0;
 }
 
-static inline unsigned long long prof_ticks(struct task_struct *p)
+static inline u64 prof_ticks(struct task_struct *p)
 {
-	cputime_t utime, stime;
+	u64 utime, stime;
 
-	task_cputime_t(p, &utime, &stime);
+	task_cputime(p, &utime, &stime);
 
-	return cputime_to_expires(utime + stime);
+	return utime + stime;
 }
-static inline unsigned long long virt_ticks(struct task_struct *p)
+static inline u64 virt_ticks(struct task_struct *p)
 {
-	cputime_t utime, stime;
+	u64 utime, stime;
 
-	task_cputime_t(p, &utime, &stime);
+	task_cputime(p, &utime, &stime);
 
-	return cputime_to_expires(utime);
+	return utime;
 }
 
 static int
@@ -176,8 +151,8 @@ posix_cpu_clock_set(const clockid_t which_clock, const struct timespec *tp)
 /*
  * Sample a per-thread clock for the given task.
  */
-static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p,
-			    unsigned long long *sample)
+static int cpu_clock_sample(const clockid_t which_clock,
+			    struct task_struct *p, u64 *sample)
 {
 	switch (CPUCLOCK_WHICH(which_clock)) {
 	default:
@@ -210,7 +185,7 @@ static inline void __update_gt_cputime(atomic64_t *cputime, u64 sum_cputime)
 	}
 }
 
-static void update_gt_cputime(struct task_cputime_atomic *cputime_atomic, struct task_cputime_t *sum)
+static void update_gt_cputime(struct task_cputime_atomic *cputime_atomic, struct task_cputime *sum)
 {
 	__update_gt_cputime(&cputime_atomic->utime, sum->utime);
 	__update_gt_cputime(&cputime_atomic->stime, sum->stime);
@@ -218,7 +193,7 @@ static void update_gt_cputime(struct task_cputime_atomic *cputime_atomic, struct
 }
 
 /* Sample task_cputime_atomic values in "atomic_timers", store results in "times". */
-static inline void sample_cputime_atomic(struct task_cputime_t *times,
+static inline void sample_cputime_atomic(struct task_cputime *times,
 					 struct task_cputime_atomic *atomic_times)
 {
 	times->utime = atomic64_read(&atomic_times->utime);
@@ -226,10 +201,10 @@ static inline void sample_cputime_atomic(struct task_cputime_t *times,
 	times->sum_exec_runtime = atomic64_read(&atomic_times->sum_exec_runtime);
 }
 
-void thread_group_cputimer(struct task_struct *tsk, struct task_cputime_t *times)
+void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
 {
 	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
-	struct task_cputime_t sum;
+	struct task_cputime sum;
 
 	/* Check if cputimer isn't running. This is accessed without locking. */
 	if (!READ_ONCE(cputimer->running)) {
@@ -238,7 +213,7 @@ void thread_group_cputimer(struct task_struct *tsk, struct task_cputime_t *times
 		 * values through the TIMER_ABSTIME flag, therefore we have
 		 * to synchronize the timer to the clock every time we start it.
 		 */
-		thread_group_cputime_t(tsk, &sum);
+		thread_group_cputime(tsk, &sum);
 		update_gt_cputime(&cputimer->cputime_atomic, &sum);
 
 		/*
@@ -260,23 +235,23 @@ void thread_group_cputimer(struct task_struct *tsk, struct task_cputime_t *times
  */
 static int cpu_clock_sample_group(const clockid_t which_clock,
 				  struct task_struct *p,
-				  unsigned long long *sample)
+				  u64 *sample)
 {
-	struct task_cputime_t cputime;
+	struct task_cputime cputime;
 
 	switch (CPUCLOCK_WHICH(which_clock)) {
 	default:
 		return -EINVAL;
 	case CPUCLOCK_PROF:
-		thread_group_cputime_t(p, &cputime);
-		*sample = cputime_to_expires(cputime.utime + cputime.stime);
+		thread_group_cputime(p, &cputime);
+		*sample = cputime.utime + cputime.stime;
 		break;
 	case CPUCLOCK_VIRT:
-		thread_group_cputime_t(p, &cputime);
-		*sample = cputime_to_expires(cputime.utime);
+		thread_group_cputime(p, &cputime);
+		*sample = cputime.utime;
 		break;
 	case CPUCLOCK_SCHED:
-		thread_group_cputime_t(p, &cputime);
+		thread_group_cputime(p, &cputime);
 		*sample = cputime.sum_exec_runtime;
 		break;
 	}
@@ -288,7 +263,7 @@ static int posix_cpu_clock_get_task(struct task_struct *tsk,
 				    struct timespec *tp)
 {
 	int err = -EINVAL;
-	unsigned long long rtn;
+	u64 rtn;
 
 	if (CPUCLOCK_PERTHREAD(which_clock)) {
 		if (same_thread_group(tsk, current))
@@ -299,7 +274,7 @@ static int posix_cpu_clock_get_task(struct task_struct *tsk,
 	}
 
 	if (!err)
-		sample_to_timespec(which_clock, rtn, tp);
+		*tp = ns_to_timespec(rtn);
 
 	return err;
 }
@@ -453,7 +428,7 @@ void posix_cpu_timers_exit_group(struct task_struct *tsk)
 	cleanup_timers(tsk->signal->cpu_timers);
 }
 
-static inline int expires_gt(cputime_t expires, cputime_t new_exp)
+static inline int expires_gt(u64 expires, u64 new_exp)
 {
 	return expires == 0 || expires > new_exp;
 }
@@ -466,7 +441,7 @@ static void arm_timer(struct k_itimer *timer)
 {
 	struct task_struct *p = timer->it.cpu.task;
 	struct list_head *head, *listpos;
-	struct task_cputime_t *cputime_expires;
+	struct task_cputime *cputime_expires;
 	struct cpu_timer_list *const nt = &timer->it.cpu;
 	struct cpu_timer_list *next;
 
@@ -488,7 +463,7 @@ static void arm_timer(struct k_itimer *timer)
 	list_add(&nt->entry, listpos);
 
 	if (listpos == head) {
-		unsigned long long exp = nt->expires;
+		u64 exp = nt->expires;
 
 		/*
 		 * We are the new earliest-expiring POSIX 1.b timer, hence
@@ -499,16 +474,15 @@ static void arm_timer(struct k_itimer *timer)
 
 		switch (CPUCLOCK_WHICH(timer->it_clock)) {
 		case CPUCLOCK_PROF:
-			if (expires_gt(cputime_expires->prof_exp, expires_to_cputime(exp)))
-				cputime_expires->prof_exp = expires_to_cputime(exp);
+			if (expires_gt(cputime_expires->prof_exp, exp))
+				cputime_expires->prof_exp = exp;
 			break;
 		case CPUCLOCK_VIRT:
-			if (expires_gt(cputime_expires->virt_exp, expires_to_cputime(exp)))
-				cputime_expires->virt_exp = expires_to_cputime(exp);
+			if (expires_gt(cputime_expires->virt_exp, exp))
+				cputime_expires->virt_exp = exp;
 			break;
 		case CPUCLOCK_SCHED:
-			if (cputime_expires->sched_exp == 0 ||
-			    cputime_expires->sched_exp > exp)
+			if (expires_gt(cputime_expires->sched_exp, exp))
 				cputime_expires->sched_exp = exp;
 			break;
 		}
@@ -559,20 +533,19 @@ static void cpu_timer_fire(struct k_itimer *timer)
  * traversal.
  */
 static int cpu_timer_sample_group(const clockid_t which_clock,
-				  struct task_struct *p,
-				  unsigned long long *sample)
+				  struct task_struct *p, u64 *sample)
 {
-	struct task_cputime_t cputime;
+	struct task_cputime cputime;
 
 	thread_group_cputimer(p, &cputime);
 	switch (CPUCLOCK_WHICH(which_clock)) {
 	default:
 		return -EINVAL;
 	case CPUCLOCK_PROF:
-		*sample = cputime_to_expires(cputime.utime + cputime.stime);
+		*sample = cputime.utime + cputime.stime;
 		break;
 	case CPUCLOCK_VIRT:
-		*sample = cputime_to_expires(cputime.utime);
+		*sample = cputime.utime;
 		break;
 	case CPUCLOCK_SCHED:
 		*sample = cputime.sum_exec_runtime;
@@ -593,12 +566,12 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
 	unsigned long flags;
 	struct sighand_struct *sighand;
 	struct task_struct *p = timer->it.cpu.task;
-	unsigned long long old_expires, new_expires, old_incr, val;
+	u64 old_expires, new_expires, old_incr, val;
 	int ret;
 
 	WARN_ON_ONCE(p == NULL);
 
-	new_expires = timespec_to_sample(timer->it_clock, &new->it_value);
+	new_expires = timespec_to_ns(&new->it_value);
 
 	/*
 	 * Protect against sighand release/switch in exit/exec and p->cpu_timers
@@ -659,9 +632,7 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
 			bump_cpu_timer(timer, val);
 			if (val < timer->it.cpu.expires) {
 				old_expires = timer->it.cpu.expires - val;
-				sample_to_timespec(timer->it_clock,
-						   old_expires,
-						   &old->it_value);
+				old->it_value = ns_to_timespec(old_expires);
 			} else {
 				old->it_value.tv_nsec = 1;
 				old->it_value.tv_sec = 0;
@@ -699,8 +670,7 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
 	 * Install the new reload setting, and
 	 * set up the signal and overrun bookkeeping.
 	 */
-	timer->it.cpu.incr = timespec_to_sample(timer->it_clock,
-						&new->it_interval);
+	timer->it.cpu.incr = timespec_to_ns(&new->it_interval);
 
 	/*
 	 * This acts as a modification timestamp for the timer,
@@ -723,17 +693,15 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
 
 	ret = 0;
  out:
-	if (old) {
-		sample_to_timespec(timer->it_clock,
-				   old_incr, &old->it_interval);
-	}
+	if (old)
+		old->it_interval = ns_to_timespec(old_incr);
 
 	return ret;
 }
 
 static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
 {
-	unsigned long long now;
+	u64 now;
 	struct task_struct *p = timer->it.cpu.task;
 
 	WARN_ON_ONCE(p == NULL);
@@ -741,8 +709,7 @@ static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
 	/*
 	 * Easy part: convert the reload time.
 	 */
-	sample_to_timespec(timer->it_clock,
-			   timer->it.cpu.incr, &itp->it_interval);
+	itp->it_interval = ns_to_timespec(timer->it.cpu.incr);
 
 	if (timer->it.cpu.expires == 0) {	/* Timer not armed at all.  */
 		itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
@@ -761,7 +728,7 @@ static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
 		/*
 		 * Protect against sighand release/switch in exit/exec and
 		 * also make timer sampling safe if it ends up calling
-		 * thread_group_cputime_t().
+		 * thread_group_cputime().
 		 */
 		sighand = lock_task_sighand(p, &flags);
 		if (unlikely(sighand == NULL)) {
@@ -771,8 +738,7 @@ static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
 			 * Call the timer disarmed, nothing else to do.
 			 */
 			timer->it.cpu.expires = 0;
-			sample_to_timespec(timer->it_clock, timer->it.cpu.expires,
-					   &itp->it_value);
+			itp->it_value = ns_to_timespec(timer->it.cpu.expires);
 			return;
 		} else {
 			cpu_timer_sample_group(timer->it_clock, p, &now);
@@ -781,9 +747,7 @@ static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
 	}
 
 	if (now < timer->it.cpu.expires) {
-		sample_to_timespec(timer->it_clock,
-				   timer->it.cpu.expires - now,
-				   &itp->it_value);
+		itp->it_value = ns_to_timespec(timer->it.cpu.expires - now);
 	} else {
 		/*
 		 * The timer should have expired already, but the firing
@@ -826,8 +790,8 @@ static void check_thread_timers(struct task_struct *tsk,
 {
 	struct list_head *timers = tsk->cpu_timers;
 	struct signal_struct *const sig = tsk->signal;
-	struct task_cputime_t *tsk_expires = &tsk->cputime_expires;
-	unsigned long long expires;
+	struct task_cputime *tsk_expires = &tsk->cputime_expires;
+	u64 expires;
 	unsigned long soft;
 
 	/*
@@ -838,10 +802,10 @@ static void check_thread_timers(struct task_struct *tsk,
 		return;
 
 	expires = check_timers_list(timers, firing, prof_ticks(tsk));
-	tsk_expires->prof_exp = expires_to_cputime(expires);
+	tsk_expires->prof_exp = expires;
 
 	expires = check_timers_list(++timers, firing, virt_ticks(tsk));
-	tsk_expires->virt_exp = expires_to_cputime(expires);
+	tsk_expires->virt_exp = expires;
 
 	tsk_expires->sched_exp = check_timers_list(++timers, firing,
 						   tsk->se.sum_exec_runtime);
@@ -891,13 +855,12 @@ static inline void stop_process_timers(struct signal_struct *sig)
 }
 
 static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
-			     unsigned long long *expires,
-			     unsigned long long cur_time, int signo)
+			     u64 *expires, u64 cur_time, int signo)
 {
 	if (!it->expires)
 		return;
 
-	if (cur_time >= it->expires) {
+	if (cur_time >= cputime_to_nsecs(it->expires)) {
 		if (it->incr) {
 			it->expires += it->incr;
 			it->error += it->incr_error;
@@ -915,8 +878,8 @@ static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
 		__group_send_sig_info(signo, SEND_SIG_PRIV, tsk);
 	}
 
-	if (it->expires && (!*expires || it->expires < *expires)) {
-		*expires = it->expires;
+	if (it->expires && (!*expires || cputime_to_nsecs(it->expires) < *expires)) {
+		*expires = cputime_to_nsecs(it->expires);
 	}
 }
 
@@ -929,10 +892,10 @@ static void check_process_timers(struct task_struct *tsk,
 				 struct list_head *firing)
 {
 	struct signal_struct *const sig = tsk->signal;
-	unsigned long long utime, ptime, virt_expires, prof_expires;
-	unsigned long long sum_sched_runtime, sched_expires;
+	u64 utime, ptime, virt_expires, prof_expires;
+	u64 sum_sched_runtime, sched_expires;
 	struct list_head *timers = sig->cpu_timers;
-	struct task_cputime_t cputime;
+	struct task_cputime cputime;
 	unsigned long soft;
 
 	/*
@@ -952,8 +915,8 @@ static void check_process_timers(struct task_struct *tsk,
 	 * Collect the current process totals.
 	 */
 	thread_group_cputimer(tsk, &cputime);
-	utime = cputime_to_expires(cputime.utime);
-	ptime = utime + cputime_to_expires(cputime.stime);
+	utime = cputime.utime;
+	ptime = utime + cputime.stime;
 	sum_sched_runtime = cputime.sum_exec_runtime;
 
 	prof_expires = check_timers_list(timers, firing, ptime);
@@ -969,10 +932,10 @@ static void check_process_timers(struct task_struct *tsk,
 			 SIGVTALRM);
 	soft = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
 	if (soft != RLIM_INFINITY) {
-		unsigned long psecs = cputime_to_secs(ptime);
+		unsigned long psecs = div_u64(ptime, NSEC_PER_SEC);
 		unsigned long hard =
 			READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_max);
-		cputime_t x;
+		u64 x;
 		if (psecs >= hard) {
 			/*
 			 * At the hard limit, we just die.
@@ -991,14 +954,13 @@ static void check_process_timers(struct task_struct *tsk,
 				sig->rlim[RLIMIT_CPU].rlim_cur = soft;
 			}
 		}
-		x = secs_to_cputime(soft);
-		if (!prof_expires || x < prof_expires) {
+		x = soft * NSEC_PER_SEC;
+		if (!prof_expires || x < prof_expires)
 			prof_expires = x;
-		}
 	}
 
-	sig->cputime_expires.prof_exp = expires_to_cputime(prof_expires);
-	sig->cputime_expires.virt_exp = expires_to_cputime(virt_expires);
+	sig->cputime_expires.prof_exp = prof_expires;
+	sig->cputime_expires.virt_exp = virt_expires;
 	sig->cputime_expires.sched_exp = sched_expires;
 	if (task_cputime_zero(&sig->cputime_expires))
 		stop_process_timers(sig);
@@ -1015,7 +977,7 @@ void posix_cpu_timer_schedule(struct k_itimer *timer)
 	struct sighand_struct *sighand;
 	unsigned long flags;
 	struct task_struct *p = timer->it.cpu.task;
-	unsigned long long now;
+	u64 now;
 
 	WARN_ON_ONCE(p == NULL);
 
@@ -1035,7 +997,7 @@ void posix_cpu_timer_schedule(struct k_itimer *timer)
 	} else {
 		/*
 		 * Protect arm_timer() and timer sampling in case of call to
-		 * thread_group_cputime_t().
+		 * thread_group_cputime().
 		 */
 		sighand = lock_task_sighand(p, &flags);
 		if (unlikely(sighand == NULL)) {
@@ -1078,8 +1040,8 @@ void posix_cpu_timer_schedule(struct k_itimer *timer)
  * Returns true if any field of the former is greater than the corresponding
  * field of the latter if the latter field is set.  Otherwise returns false.
  */
-static inline int task_cputime_expired(const struct task_cputime_t *sample,
-					const struct task_cputime_t *expires)
+static inline int task_cputime_expired(const struct task_cputime *sample,
+					const struct task_cputime *expires)
 {
 	if (expires->utime && sample->utime >= expires->utime)
 		return 1;
@@ -1106,9 +1068,9 @@ static inline int fastpath_timer_check(struct task_struct *tsk)
 	struct signal_struct *sig;
 
 	if (!task_cputime_zero(&tsk->cputime_expires)) {
-		struct task_cputime_t task_sample;
+		struct task_cputime task_sample;
 
-		task_cputime_t(tsk, &task_sample.utime, &task_sample.stime);
+		task_cputime(tsk, &task_sample.utime, &task_sample.stime);
 		task_sample.sum_exec_runtime = tsk->se.sum_exec_runtime;
 		if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
 			return 1;
@@ -1131,7 +1093,7 @@ static inline int fastpath_timer_check(struct task_struct *tsk)
 	 */
 	if (READ_ONCE(sig->cputimer.running) &&
 	    !READ_ONCE(sig->cputimer.checking_timer)) {
-		struct task_cputime_t group_sample;
+		struct task_cputime group_sample;
 
 		sample_cputime_atomic(&group_sample, &sig->cputimer.cputime_atomic);
 
@@ -1214,7 +1176,7 @@ void run_posix_cpu_timers(struct task_struct *tsk)
 void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
 			   cputime_t *newval, cputime_t *oldval)
 {
-	unsigned long long now;
+	u64 now, new;
 
 	WARN_ON_ONCE(clock_idx == CPUCLOCK_SCHED);
 	cpu_timer_sample_group(clock_idx, tsk, &now);
@@ -1226,31 +1188,33 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
 		 * it to be absolute.
 		 */
 		if (*oldval) {
-			if (*oldval <= now) {
+			if (cputime_to_nsecs(*oldval) <= now) {
 				/* Just about to fire. */
 				*oldval = cputime_one_jiffy;
 			} else {
-				*oldval -= now;
+				*oldval -= nsecs_to_cputime(now);
 			}
 		}
 
 		if (!*newval)
 			return;
-		*newval += now;
+		*newval += nsecs_to_cputime(now);
 	}
 
+	new = cputime_to_nsecs(*newval);
+
 	/*
 	 * Update expiration cache if we are the earliest timer, or eventually
 	 * RLIMIT_CPU limit is earlier than prof_exp cpu timer expire.
 	 */
 	switch (clock_idx) {
 	case CPUCLOCK_PROF:
-		if (expires_gt(tsk->signal->cputime_expires.prof_exp, *newval))
-			tsk->signal->cputime_expires.prof_exp = *newval;
+		if (expires_gt(tsk->signal->cputime_expires.prof_exp, new))
+			tsk->signal->cputime_expires.prof_exp = new;
 		break;
 	case CPUCLOCK_VIRT:
-		if (expires_gt(tsk->signal->cputime_expires.virt_exp, *newval))
-			tsk->signal->cputime_expires.virt_exp = *newval;
+		if (expires_gt(tsk->signal->cputime_expires.virt_exp, new))
+			tsk->signal->cputime_expires.virt_exp = new;
 		break;
 	}
 
@@ -1308,7 +1272,7 @@ static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
 		/*
 		 * We were interrupted by a signal.
 		 */
-		sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp);
+		*rqtp = ns_to_timespec(timer.it.cpu.expires);
 		error = posix_cpu_timer_set(&timer, 0, &zero_it, it);
 		if (!error) {
 			/*
-- 
2.7.4