[PATCH] time/hrtimer: Embed hrtimer mode into hrtimer_sleeper

[Juri Lelli]

Changes to hrtimer mode (potentially made by __hrtimer_init_sleeper() on
PREEMPT_RT) are not visible to do_nanosleep(), thus not accounted for
by hrtimer_start_expires() call paths.

Embed hrtimer mode into hrtimer_sleeper struct, so that the same mode is
used by code following hrtimer_sleeper initialization.

Signed-off-by: Juri Lelli <juri.lelli@xxxxxxxxxx>
---
 block/blk-mq.c          | 2 +-
 include/linux/hrtimer.h | 1 +
 include/linux/wait.h    | 2 +-
 kernel/futex/pi.c       | 2 +-
 kernel/time/hrtimer.c   | 7 ++++---
 net/core/pktgen.c       | 2 +-
 6 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 03235ed3a792..429d5f08a7c4 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -4672,7 +4672,7 @@ static bool blk_mq_poll_hybrid(struct request_queue *q, blk_qc_t qc)
 		if (blk_mq_rq_state(rq) == MQ_RQ_COMPLETE)
 			break;
 		set_current_state(TASK_UNINTERRUPTIBLE);
-		hrtimer_sleeper_start_expires(&hs, mode);
+		hrtimer_sleeper_start_expires(&hs, hs.mode);
 		if (hs.task)
 			io_schedule();
 		hrtimer_cancel(&hs.timer);
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index d22418264bec..90f79b4e20c8 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -140,6 +140,7 @@ struct hrtimer {
 struct hrtimer_sleeper {
 	struct hrtimer timer;
 	struct task_struct *task;
+	enum hrtimer_mode mode;
 };
 
 #ifdef CONFIG_64BIT
diff --git a/include/linux/wait.h b/include/linux/wait.h
index 2d0df57c9902..b7499818f2c7 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -521,7 +521,7 @@ do {										\
 	if ((timeout) != KTIME_MAX)						\
 		hrtimer_start_range_ns(&__t.timer, timeout,			\
 				       current->timer_slack_ns,			\
-				       HRTIMER_MODE_REL);			\
+				       __t.mode);				\
 										\
 	__ret = ___wait_event(wq_head, condition, state, 0, 0,			\
 		if (!__t.task) {						\
diff --git a/kernel/futex/pi.c b/kernel/futex/pi.c
index 183b28c32c83..c576e84d96c9 100644
--- a/kernel/futex/pi.c
+++ b/kernel/futex/pi.c
@@ -1034,7 +1034,7 @@ int futex_lock_pi(u32 __user *uaddr, unsigned int flags, ktime_t *time, int tryl
 	}
 
 	if (unlikely(to))
-		hrtimer_sleeper_start_expires(to, HRTIMER_MODE_ABS);
+		hrtimer_sleeper_start_expires(to, to->mode);
 
 	ret = rt_mutex_wait_proxy_lock(&q.pi_state->pi_mutex, to, &rt_waiter);
 
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 0ea8702eb516..0019c802e2e8 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -1996,6 +1996,7 @@ static void __hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
 	__hrtimer_init(&sl->timer, clock_id, mode);
 	sl->timer.function = hrtimer_wakeup;
 	sl->task = current;
+	sl->mode = mode;
 }
 
 /**
@@ -2075,7 +2076,7 @@ static long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
 	hrtimer_init_sleeper_on_stack(&t, restart->nanosleep.clockid,
 				      HRTIMER_MODE_ABS);
 	hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
-	ret = do_nanosleep(&t, HRTIMER_MODE_ABS);
+	ret = do_nanosleep(&t, t.mode);
 	destroy_hrtimer_on_stack(&t.timer);
 	return ret;
 }
@@ -2094,7 +2095,7 @@ long hrtimer_nanosleep(ktime_t rqtp, const enum hrtimer_mode mode,
 
 	hrtimer_init_sleeper_on_stack(&t, clockid, mode);
 	hrtimer_set_expires_range_ns(&t.timer, rqtp, slack);
-	ret = do_nanosleep(&t, mode);
+	ret = do_nanosleep(&t, t.mode);
 	if (ret != -ERESTART_RESTARTBLOCK)
 		goto out;
 
@@ -2299,7 +2300,7 @@ schedule_hrtimeout_range_clock(ktime_t *expires, u64 delta,
 
 	hrtimer_init_sleeper_on_stack(&t, clock_id, mode);
 	hrtimer_set_expires_range_ns(&t.timer, *expires, delta);
-	hrtimer_sleeper_start_expires(&t, mode);
+	hrtimer_sleeper_start_expires(&t, t.mode);
 
 	if (likely(t.task))
 		schedule();
diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index 82c016e8c196..51eddba28c03 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -2169,7 +2169,7 @@ static void spin(struct pktgen_dev *pkt_dev, ktime_t spin_until)
 	} else {
 		do {
 			set_current_state(TASK_INTERRUPTIBLE);
-			hrtimer_sleeper_start_expires(&t, HRTIMER_MODE_ABS);
+			hrtimer_sleeper_start_expires(&t, t.mode);
 
 			if (likely(t.task))
 				schedule();
-- 
2.36.1