2 files changed, 30 insertions, 34 deletions

diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 8512f06f0..bf74f43e4 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -1922,29 +1922,22 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
 	}
 }
 
-int hrtimers_dead_cpu(unsigned int scpu)
+int hrtimers_cpu_dying(unsigned int dying_cpu)
 {
 	struct hrtimer_cpu_base *old_base, *new_base;
-	int i;
+	int i, ncpu = cpumask_first(cpu_active_mask);
 
-	BUG_ON(cpu_online(scpu));
-	tick_cancel_sched_timer(scpu);
+	tick_cancel_sched_timer(dying_cpu);
+
+	old_base = this_cpu_ptr(&hrtimer_bases);
+	new_base = &per_cpu(hrtimer_bases, ncpu);
 
-	/*
-	 * this BH disable ensures that raise_softirq_irqoff() does
-	 * not wakeup ksoftirqd (and acquire the pi-lock) while
-	 * holding the cpu_base lock
-	 */
-	local_bh_disable();
-	local_irq_disable();
-	old_base = &per_cpu(hrtimer_bases, scpu);
-	new_base = this_cpu_ptr(&hrtimer_bases);
 	/*
 	 * The caller is globally serialized and nobody else
 	 * takes two locks at once, deadlock is not possible.
 	 */
-	raw_spin_lock(&new_base->lock);
-	raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
+	raw_spin_lock(&old_base->lock);
+	raw_spin_lock_nested(&new_base->lock, SINGLE_DEPTH_NESTING);
 
 	for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
 		migrate_hrtimer_list(&old_base->clock_base[i],
@@ -1955,15 +1948,13 @@ int hrtimers_dead_cpu(unsigned int scpu)
 	 * The migration might have changed the first expiring softirq
 	 * timer on this CPU. Update it.
 	 */
-	hrtimer_update_softirq_timer(new_base, false);
+	__hrtimer_get_next_event(new_base, HRTIMER_ACTIVE_SOFT);
+	/* Tell the other CPU to retrigger the next event */
+	smp_call_function_single(ncpu, retrigger_next_event, NULL, 0);
 
-	raw_spin_unlock(&old_base->lock);
 	raw_spin_unlock(&new_base->lock);
+	raw_spin_unlock(&old_base->lock);
 
-	/* Check, if we got expired work to do */
-	__hrtimer_peek_ahead_timers();
-	local_irq_enable();
-	local_bh_enable();
 	return 0;
 }
 
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index 1234868b3..8768ce2c4 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -159,25 +159,30 @@ static struct k_itimer *posix_timer_by_id(timer_t id)
 static int posix_timer_add(struct k_itimer *timer)
 {
 	struct signal_struct *sig = current->signal;
-	int first_free_id = sig->posix_timer_id;
 	struct hlist_head *head;
-	int ret = -ENOENT;
+	unsigned int cnt, id;
 
-	do {
+	/*
+	 * FIXME: Replace this by a per signal struct xarray once there is
+	 * a plan to handle the resulting CRIU regression gracefully.
+	 */
+	for (cnt = 0; cnt <= INT_MAX; cnt++) {
 		spin_lock(&hash_lock);
-		head = &posix_timers_hashtable[hash(sig, sig->posix_timer_id)];
-		if (!__posix_timers_find(head, sig, sig->posix_timer_id)) {
+		id = sig->next_posix_timer_id;
+
+		/* Write the next ID back. Clamp it to the positive space */
+		sig->next_posix_timer_id = (id + 1) & INT_MAX;
+
+		head = &posix_timers_hashtable[hash(sig, id)];
+		if (!__posix_timers_find(head, sig, id)) {
 			hlist_add_head_rcu(&timer->t_hash, head);
-			ret = sig->posix_timer_id;
+			spin_unlock(&hash_lock);
+			return id;
 		}
-		if (++sig->posix_timer_id < 0)
-			sig->posix_timer_id = 0;
-		if ((sig->posix_timer_id == first_free_id) && (ret == -ENOENT))
-			/* Loop over all possible ids completed */
-			ret = -EAGAIN;
 		spin_unlock(&hash_lock);
-	} while (ret == -ENOENT);
-	return ret;
+	}
+	/* POSIX return code when no timer ID could be allocated */
+	return -EAGAIN;
 }
 
 static inline void unlock_timer(struct k_itimer *timr, unsigned long flags)