From 379108ca910b3d4b3b12c1f8b48a06b2d3009d06 Mon Sep 17 00:00:00 2001
From: Jamie Liu <jamieliu@google.com>
Date: Thu, 7 Nov 2024 11:43:42 -0800
Subject: [PATCH] ktime: simplify Listener.NotifyTimer()

No implementations of Listener use the Setting argument or the ability to
override the new Setting, so remove these.

PiperOrigin-RevId: 694195729
---
 pkg/sentry/fsimpl/timerfd/timerfd.go |  3 +--
 pkg/sentry/kernel/posixtimer.go      |  8 +++-----
 pkg/sentry/kernel/thread_group.go    |  3 +--
 pkg/sentry/ktime/ktime.go            | 25 ++++++-------------------
 pkg/sentry/ktime/util.go             |  3 +--
 5 files changed, 12 insertions(+), 30 deletions(-)

diff --git a/pkg/sentry/fsimpl/timerfd/timerfd.go b/pkg/sentry/fsimpl/timerfd/timerfd.go
index 7e8627165..b727db9c6 100644
--- a/pkg/sentry/fsimpl/timerfd/timerfd.go
+++ b/pkg/sentry/fsimpl/timerfd/timerfd.go
@@ -142,8 +142,7 @@ func (tfd *TimerFileDescription) Release(context.Context) {
 }
 
 // NotifyTimer implements ktime.TimerListener.NotifyTimer.
-func (tfd *TimerFileDescription) NotifyTimer(exp uint64, setting ktime.Setting) (ktime.Setting, bool) {
+func (tfd *TimerFileDescription) NotifyTimer(exp uint64) {
 	tfd.val.Add(exp)
 	tfd.events.Notify(waiter.ReadableEvents)
-	return ktime.Setting{}, false
 }
diff --git a/pkg/sentry/kernel/posixtimer.go b/pkg/sentry/kernel/posixtimer.go
index 21a9de041..956931157 100644
--- a/pkg/sentry/kernel/posixtimer.go
+++ b/pkg/sentry/kernel/posixtimer.go
@@ -114,9 +114,9 @@ func (it *IntervalTimer) signalRejectedLocked() {
 }
 
 // NotifyTimer implements ktime.TimerListener.NotifyTimer.
-func (it *IntervalTimer) NotifyTimer(exp uint64, setting ktime.Setting) (ktime.Setting, bool) {
+func (it *IntervalTimer) NotifyTimer(exp uint64) {
 	if it.target == nil {
-		return ktime.Setting{}, false
+		return
 	}
 
 	sh := it.target.tg.signalLock()
@@ -124,7 +124,7 @@ func (it *IntervalTimer) NotifyTimer(exp uint64, setting ktime.Setting) (ktime.S
 
 	if it.sigpending {
 		it.overrunCur += exp
-		return ktime.Setting{}, false
+		return
 	}
 
 	// sigpending must be set before sendSignalTimerLocked() so that it can be
@@ -143,8 +143,6 @@ func (it *IntervalTimer) NotifyTimer(exp uint64, setting ktime.Setting) (ktime.S
 	if err := it.target.sendSignalTimerLocked(si, it.group, it); err != nil {
 		it.signalRejectedLocked()
 	}
-
-	return ktime.Setting{}, false
 }
 
 // IntervalTimerCreate implements timer_create(2).
diff --git a/pkg/sentry/kernel/thread_group.go b/pkg/sentry/kernel/thread_group.go
index cddeb21d4..7f1fd494c 100644
--- a/pkg/sentry/kernel/thread_group.go
+++ b/pkg/sentry/kernel/thread_group.go
@@ -658,7 +658,6 @@ type itimerRealListener struct {
 }
 
 // NotifyTimer implements ktime.TimerListener.NotifyTimer.
-func (l *itimerRealListener) NotifyTimer(exp uint64, setting ktime.Setting) (ktime.Setting, bool) {
+func (l *itimerRealListener) NotifyTimer(exp uint64) {
 	l.tg.SendSignal(SignalInfoPriv(linux.SIGALRM))
-	return ktime.Setting{}, false
 }
diff --git a/pkg/sentry/ktime/ktime.go b/pkg/sentry/ktime/ktime.go
index 4d22e2a6d..7276281e1 100644
--- a/pkg/sentry/ktime/ktime.go
+++ b/pkg/sentry/ktime/ktime.go
@@ -298,11 +298,8 @@ type Listener interface {
 	// Notify is called with the associated Timer's mutex locked, so Notify
 	// must not take any locks that precede Timer.mu in lock order.
 	//
-	// If Notify returns true, the timer will use the returned setting
-	// rather than the passed one.
-	//
 	// Preconditions: exp > 0.
-	NotifyTimer(exp uint64, setting Setting) (newSetting Setting, update bool)
+	NotifyTimer(exp uint64)
 }
 
 // Setting contains user-controlled mutable Timer properties.
@@ -551,9 +548,7 @@ func (t *Timer) Tick() {
 	s, exp := t.setting.At(now)
 	t.setting = s
 	if exp > 0 {
-		if newS, ok := t.listener.NotifyTimer(exp, t.setting); ok {
-			t.setting = newS
-		}
+		t.listener.NotifyTimer(exp)
 	}
 	t.resetKickerLocked(now)
 }
@@ -617,9 +612,7 @@ func (t *Timer) Get() (Time, Setting) {
 	s, exp := t.setting.At(now)
 	t.setting = s
 	if exp > 0 {
-		if newS, ok := t.listener.NotifyTimer(exp, t.setting); ok {
-			t.setting = newS
-		}
+		t.listener.NotifyTimer(exp)
 	}
 	t.resetKickerLocked(now)
 	return now, s
@@ -659,9 +652,7 @@ func (t *Timer) SwapAnd(s Setting, f func()) (Time, Setting) {
 	}
 	oldS, oldExp := t.setting.At(now)
 	if oldExp > 0 {
-		t.listener.NotifyTimer(oldExp, oldS)
-		// N.B. The returned Setting doesn't matter because we're about
-		// to overwrite.
+		t.listener.NotifyTimer(oldExp)
 	}
 	if f != nil {
 		f()
@@ -669,9 +660,7 @@ func (t *Timer) SwapAnd(s Setting, f func()) (Time, Setting) {
 	newS, newExp := s.At(now)
 	t.setting = newS
 	if newExp > 0 {
-		if newS, ok := t.listener.NotifyTimer(newExp, t.setting); ok {
-			t.setting = newS
-		}
+		t.listener.NotifyTimer(newExp)
 	}
 	t.resetKickerLocked(now)
 	return now, oldS
@@ -730,11 +719,9 @@ func NewChannelNotifier() (Listener, <-chan struct{}) {
 }
 
 // NotifyTimer implements Listener.NotifyTimer.
-func (c ChannelNotifier) NotifyTimer(uint64, Setting) (Setting, bool) {
+func (c ChannelNotifier) NotifyTimer(uint64) {
 	select {
 	case c <- struct{}{}:
 	default:
 	}
-
-	return Setting{}, false
 }
diff --git a/pkg/sentry/ktime/util.go b/pkg/sentry/ktime/util.go
index bd78f8677..c7afbee2d 100644
--- a/pkg/sentry/ktime/util.go
+++ b/pkg/sentry/ktime/util.go
@@ -122,7 +122,6 @@ type functionNotifier struct {
 }
 
 // NotifyTimer implements ktime.TimerListener.NotifyTimer.
-func (f *functionNotifier) NotifyTimer(uint64, Setting) (Setting, bool) {
+func (f *functionNotifier) NotifyTimer(uint64) {
 	f.fn()
-	return Setting{}, false
 }