[tip:timers/core] posix-timers: Store k_clock pointer in k_itimer

[tip-bot for Thomas Gleixner]

Commit-ID:  d97bb75ddd2f38068df01da8abf26df78756253c
Gitweb:     http://git.kernel.org/tip/d97bb75ddd2f38068df01da8abf26df78756253c
Author:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Tue, 30 May 2017 23:15:44 +0200
Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Sun, 4 Jun 2017 15:40:25 +0200

posix-timers: Store k_clock pointer in k_itimer

Having the k_clock pointer in the k_itimer struct avoids the lookup in
several code pathes and makes the next steps of unification of the hrtimer
and alarmtimer based posix timers simpler.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: John Stultz <john.stultz@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/20170530211656.641222072@xxxxxxxxxxxxx

---
 include/linux/posix-timers.h   | 2 ++
 kernel/time/posix-cpu-timers.c | 2 ++
 kernel/time/posix-timers.c     | 7 ++++---
 3 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
index 908048f..8f9cca3 100644
--- a/include/linux/posix-timers.h
+++ b/include/linux/posix-timers.h
@@ -56,6 +56,7 @@ struct cpu_timer_list {
  * @list:		List head for binding the timer to signals->posix_timers
  * @t_hash:		Entry in the posix timer hash table
  * @it_lock:		Lock protecting the timer
+ * @kclock:		Pointer to the k_clock struct handling this timer
  * @it_clock:		The posix timer clock id
  * @it_id:		The posix timer id for identifying the timer
  * @it_overrun:		The overrun counter for pending signals
@@ -75,6 +76,7 @@ struct k_itimer {
 	struct list_head	list;
 	struct hlist_node	t_hash;
 	spinlock_t		it_lock;
+	const struct k_clock	*kclock;
 	clockid_t		it_clock;
 	timer_t			it_id;
 	int			it_overrun;
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index 1683e50..0123ece 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -324,6 +324,8 @@ static int posix_cpu_timer_create(struct k_itimer *new_timer)
 	if (CPUCLOCK_WHICH(new_timer->it_clock) >= CPUCLOCK_MAX)
 		return -EINVAL;
 
+	new_timer->kclock = &clock_posix_cpu;
+
 	INIT_LIST_HEAD(&new_timer->it.cpu.entry);
 
 	rcu_read_lock();
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index 7dd992c..eb007e1 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -519,6 +519,7 @@ SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock,
 	it_id_set = IT_ID_SET;
 	new_timer->it_id = (timer_t) new_timer_id;
 	new_timer->it_clock = which_clock;
+	new_timer->kclock = kc;
 	new_timer->it_overrun = -1;
 
 	if (timer_event_spec) {
@@ -679,7 +680,7 @@ SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id,
 	if (!timr)
 		return -EINVAL;
 
-	kc = clockid_to_kclock(timr->it_clock);
+	kc = timr->kclock;
 	if (WARN_ON_ONCE(!kc || !kc->timer_get))
 		ret = -EINVAL;
 	else
@@ -798,7 +799,7 @@ retry:
 	if (!timr)
 		return -EINVAL;
 
-	kc = clockid_to_kclock(timr->it_clock);
+	kc = timr->kclock;
 	if (WARN_ON_ONCE(!kc || !kc->timer_set))
 		error = -EINVAL;
 	else
@@ -829,7 +830,7 @@ static int common_timer_del(struct k_itimer *timer)
 
 static inline int timer_delete_hook(struct k_itimer *timer)
 {
-	const struct k_clock *kc = clockid_to_kclock(timer->it_clock);
+	const struct k_clock *kc = timer->kclock;
 
 	if (WARN_ON_ONCE(!kc || !kc->timer_del))
 		return -EINVAL;