Revert: Unify CLOCK_MONOTONIC and CLOCK_BOOTTIME

Revert commits

92af4dcb4e1c ("tracing: Unify the "boot" and "mono" tracing clocks")
127bfa5f4342 ("hrtimer: Unify MONOTONIC and BOOTTIME clock behavior")
7250a4047aa6 ("posix-timers: Unify MONOTONIC and BOOTTIME clock behavior")
d6c7270e913d ("timekeeping: Remove boot time specific code")
f2d6fdbfd238 ("Input: Evdev - unify MONOTONIC and BOOTTIME clock behavior")
d6ed449afdb3 ("timekeeping: Make the MONOTONIC clock behave like the BOOTTIME clock")
72199320d49d ("timekeeping: Add the new CLOCK_MONOTONIC_ACTIVE clock")

As stated in the pull request for the unification of CLOCK_MONOTONIC and
CLOCK_BOOTTIME, it was clear that we might have to revert the change.

As reported by several folks systemd and other applications rely on the
documented behaviour of CLOCK_MONOTONIC on Linux and break with the above
changes. After resume daemons time out and other timeout related issues are
observed. Rafael compiled this list:

* systemd kills daemons on resume, after >WatchdogSec seconds
  of suspending (Genki Sky).  [Verified that that's because systemd uses
  CLOCK_MONOTONIC and expects it to not include the suspend time.]

* systemd-journald misbehaves after resume:
  systemd-journald[7266]: File /var/log/journal/016627c3c4784cd4812d4b7e96a34226/system.journal
corrupted or uncleanly shut down, renaming and replacing.
  (Mike Galbraith).

* NetworkManager reports "networking disabled" and networking is broken
  after resume 50% of the time (Pavel).  [May be because of systemd.]

* MATE desktop dims the display and starts the screensaver right after
  system resume (Pavel).

* Full system hang during resume (me).  [May be due to systemd or NM or both.]

That happens on debian and open suse systems.

It's sad, that these problems were neither catched in -next nor by those
folks who expressed interest in this change.

Reported-by: Rafael J. Wysocki <rjw@rjwysocki.net>
Reported-by: Genki Sky <sky@genki.is>,
Reported-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Easton <kevin@guarana.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Salyzyn <salyzyn@android.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>

4 files changed, 27 insertions, 15 deletions

diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index a2656c3ebe81..3892e9c8b2de 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -161,9 +161,11 @@ struct hrtimer_clock_base {
 enum  hrtimer_base_type {
 	HRTIMER_BASE_MONOTONIC,
 	HRTIMER_BASE_REALTIME,
+	HRTIMER_BASE_BOOTTIME,
 	HRTIMER_BASE_TAI,
 	HRTIMER_BASE_MONOTONIC_SOFT,
 	HRTIMER_BASE_REALTIME_SOFT,
+	HRTIMER_BASE_BOOTTIME_SOFT,
 	HRTIMER_BASE_TAI_SOFT,
 	HRTIMER_MAX_CLOCK_BASES,
 };
diff --git a/include/linux/timekeeper_internal.h b/include/linux/timekeeper_internal.h
index 4b3dca173e89..7acb953298a7 100644
--- a/include/linux/timekeeper_internal.h
+++ b/include/linux/timekeeper_internal.h
@@ -52,7 +52,6 @@ struct tk_read_base {
  * @offs_real:		Offset clock monotonic -> clock realtime
  * @offs_boot:		Offset clock monotonic -> clock boottime
  * @offs_tai:		Offset clock monotonic -> clock tai
- * @time_suspended:	Accumulated suspend time
  * @tai_offset:		The current UTC to TAI offset in seconds
  * @clock_was_set_seq:	The sequence number of clock was set events
  * @cs_was_changed_seq:	The sequence number of clocksource change events
@@ -95,7 +94,6 @@ struct timekeeper {
 	ktime_t			offs_real;
 	ktime_t			offs_boot;
 	ktime_t			offs_tai;
-	ktime_t			time_suspended;
 	s32			tai_offset;
 	unsigned int		clock_was_set_seq;
 	u8			cs_was_changed_seq;
diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index 9737fbec7019..588a0e4b1ab9 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -33,25 +33,20 @@ extern void ktime_get_ts64(struct timespec64 *ts);
 extern time64_t ktime_get_seconds(void);
 extern time64_t __ktime_get_real_seconds(void);
 extern time64_t ktime_get_real_seconds(void);
-extern void ktime_get_active_ts64(struct timespec64 *ts);
 
 extern int __getnstimeofday64(struct timespec64 *tv);
 extern void getnstimeofday64(struct timespec64 *tv);
 extern void getboottime64(struct timespec64 *ts);
 
-#define ktime_get_real_ts64(ts)		getnstimeofday64(ts)
-
-/* Clock BOOTTIME compatibility wrappers */
-static inline void get_monotonic_boottime64(struct timespec64 *ts)
-{
-	ktime_get_ts64(ts);
-}
+#define ktime_get_real_ts64(ts)	getnstimeofday64(ts)
 
 /*
  * ktime_t based interfaces
  */
+
 enum tk_offsets {
 	TK_OFFS_REAL,
+	TK_OFFS_BOOT,
 	TK_OFFS_TAI,
 	TK_OFFS_MAX,
 };
@@ -62,10 +57,6 @@ extern ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs);
 extern ktime_t ktime_get_raw(void);
 extern u32 ktime_get_resolution_ns(void);
 
-/* Clock BOOTTIME compatibility wrappers */
-static inline ktime_t ktime_get_boottime(void) { return ktime_get(); }
-static inline u64 ktime_get_boot_ns(void) { return ktime_get(); }
-
 /**
  * ktime_get_real - get the real (wall-) time in ktime_t format
  */
@@ -75,6 +66,17 @@ static inline ktime_t ktime_get_real(void)
 }
 
 /**
+ * ktime_get_boottime - Returns monotonic time since boot in ktime_t format
+ *
+ * This is similar to CLOCK_MONTONIC/ktime_get, but also includes the
+ * time spent in suspend.
+ */
+static inline ktime_t ktime_get_boottime(void)
+{
+	return ktime_get_with_offset(TK_OFFS_BOOT);
+}
+
+/**
  * ktime_get_clocktai - Returns the TAI time of day in ktime_t format
  */
 static inline ktime_t ktime_get_clocktai(void)
@@ -100,6 +102,11 @@ static inline u64 ktime_get_real_ns(void)
 	return ktime_to_ns(ktime_get_real());
 }
 
+static inline u64 ktime_get_boot_ns(void)
+{
+	return ktime_to_ns(ktime_get_boottime());
+}
+
 static inline u64 ktime_get_tai_ns(void)
 {
 	return ktime_to_ns(ktime_get_clocktai());
@@ -112,11 +119,17 @@ static inline u64 ktime_get_raw_ns(void)
 
 extern u64 ktime_get_mono_fast_ns(void);
 extern u64 ktime_get_raw_fast_ns(void);
+extern u64 ktime_get_boot_fast_ns(void);
 extern u64 ktime_get_real_fast_ns(void);
 
 /*
  * timespec64 interfaces utilizing the ktime based ones
  */
+static inline void get_monotonic_boottime64(struct timespec64 *ts)
+{
+	*ts = ktime_to_timespec64(ktime_get_boottime());
+}
+
 static inline void timekeeping_clocktai64(struct timespec64 *ts)
 {
 	*ts = ktime_to_timespec64(ktime_get_clocktai());
diff --git a/include/uapi/linux/time.h b/include/uapi/linux/time.h
index 16a296612ba4..4c0338ea308a 100644
--- a/include/uapi/linux/time.h
+++ b/include/uapi/linux/time.h
@@ -73,7 +73,6 @@ struct __kernel_old_timeval {
  */
 #define CLOCK_SGI_CYCLE			10
 #define CLOCK_TAI			11
-#define CLOCK_MONOTONIC_ACTIVE		12
 
 #define MAX_CLOCKS			16
 #define CLOCKS_MASK			(CLOCK_REALTIME | CLOCK_MONOTONIC)