---

yaml
---
r: 248631
b: refs/heads/master
c: 99ee531
h: refs/heads/master
i:
  248629: f20bb54
  248627: c688706
  248623: 0b97740
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b12a03ce4880bd13786a98db6de494a3e0123129
+refs/heads/master: 99ee5315dac6211e972fa3f23bcc9a0343ff58c4

trunk/fs/timerfd.c

@@ -26,10 +26,12 @@
 struct timerfd_ctx {
 	struct hrtimer tmr;
 	ktime_t tintv;
+	ktime_t moffs;
 	wait_queue_head_t wqh;
 	u64 ticks;
 	int expired;
 	int clockid;
+	bool might_cancel;
 };
 
 /*
@@ -59,24 +61,52 @@ static ktime_t timerfd_get_remaining(struct timerfd_ctx *ctx)
 	return remaining.tv64 < 0 ? ktime_set(0, 0): remaining;
 }
 
-static void timerfd_setup(struct timerfd_ctx *ctx, int flags,
-			  const struct itimerspec *ktmr)
+static bool timerfd_canceled(struct timerfd_ctx *ctx)
+{
+	ktime_t moffs;
+
+	if (!ctx->might_cancel)
+		return false;
+
+	moffs = ktime_get_monotonic_offset();
+
+	if (moffs.tv64 == ctx->moffs.tv64)
+		return false;
+
+	ctx->moffs = moffs;
+	return true;
+}
+
+static int timerfd_setup(struct timerfd_ctx *ctx, int flags,
+			 const struct itimerspec *ktmr)
 {
 	enum hrtimer_mode htmode;
 	ktime_t texp;
+	int clockid = ctx->clockid;
 
 	htmode = (flags & TFD_TIMER_ABSTIME) ?
 		HRTIMER_MODE_ABS: HRTIMER_MODE_REL;
 
+	ctx->might_cancel = false;
+	if (htmode == HRTIMER_MODE_ABS && ctx->clockid == CLOCK_REALTIME &&
+	    (flags & TFD_TIMER_CANCELON_SET)) {
+		clockid = CLOCK_REALTIME_COS;
+		ctx->might_cancel = true;
+	}
+
 	texp = timespec_to_ktime(ktmr->it_value);
 	ctx->expired = 0;
 	ctx->ticks = 0;
 	ctx->tintv = timespec_to_ktime(ktmr->it_interval);
-	hrtimer_init(&ctx->tmr, ctx->clockid, htmode);
+	hrtimer_init(&ctx->tmr, clockid, htmode);
 	hrtimer_set_expires(&ctx->tmr, texp);
 	ctx->tmr.function = timerfd_tmrproc;
-	if (texp.tv64 != 0)
+	if (texp.tv64 != 0) {
 		hrtimer_start(&ctx->tmr, texp, htmode);
+		if (timerfd_canceled(ctx))
+			return -ECANCELED;
+	}
+	return 0;
 }
 
 static int timerfd_release(struct inode *inode, struct file *file)
@@ -118,8 +148,21 @@ static ssize_t timerfd_read(struct file *file, char __user *buf, size_t count,
 		res = -EAGAIN;
 	else
 		res = wait_event_interruptible_locked_irq(ctx->wqh, ctx->ticks);
+
 	if (ctx->ticks) {
 		ticks = ctx->ticks;
+
+		/*
+		 * If clock has changed, we do not care about the
+		 * ticks and we do not rearm the timer. Userspace must
+		 * reevaluate anyway.
+		 */
+		if (timerfd_canceled(ctx)) {
+			ticks = 0;
+			ctx->expired = 0;
+			res = -ECANCELED;
+		}
+
 		if (ctx->expired && ctx->tintv.tv64) {
 			/*
 			 * If tintv.tv64 != 0, this is a periodic timer that
@@ -183,6 +226,7 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags)
 	init_waitqueue_head(&ctx->wqh);
 	ctx->clockid = clockid;
 	hrtimer_init(&ctx->tmr, clockid, HRTIMER_MODE_ABS);
+	ctx->moffs = ktime_get_monotonic_offset();
 
 	ufd = anon_inode_getfd("[timerfd]", &timerfd_fops, ctx,
 			       O_RDWR | (flags & TFD_SHARED_FCNTL_FLAGS));
@@ -199,6 +243,7 @@ SYSCALL_DEFINE4(timerfd_settime, int, ufd, int, flags,
 	struct file *file;
 	struct timerfd_ctx *ctx;
 	struct itimerspec ktmr, kotmr;
+	int ret;
 
 	if (copy_from_user(&ktmr, utmr, sizeof(ktmr)))
 		return -EFAULT;
@@ -240,14 +285,14 @@ SYSCALL_DEFINE4(timerfd_settime, int, ufd, int, flags,
 	/*
 	 * Re-program the timer to the new value ...
 	 */
-	timerfd_setup(ctx, flags, &ktmr);
+	ret = timerfd_setup(ctx, flags, &ktmr);
 
 	spin_unlock_irq(&ctx->wqh.lock);
 	fput(file);
 	if (otmr && copy_to_user(otmr, &kotmr, sizeof(kotmr)))
 		return -EFAULT;
 
-	return 0;
+	return ret;
 }
 
 SYSCALL_DEFINE2(timerfd_gettime, int, ufd, struct itimerspec __user *, otmr)

trunk/include/linux/hrtimer.h

@@ -155,6 +155,7 @@ enum  hrtimer_base_type {
 	HRTIMER_BASE_REALTIME,
 	HRTIMER_BASE_MONOTONIC,
 	HRTIMER_BASE_BOOTTIME,
+	HRTIMER_BASE_REALTIME_COS,
 	HRTIMER_MAX_CLOCK_BASES,
 };
 
@@ -310,6 +311,7 @@ extern void hrtimers_resume(void);
 extern ktime_t ktime_get(void);
 extern ktime_t ktime_get_real(void);
 extern ktime_t ktime_get_boottime(void);
+extern ktime_t ktime_get_monotonic_offset(void);
 
 DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
 

trunk/include/linux/time.h

@@ -302,6 +302,12 @@ struct itimerval {
  * The IDs of various hardware clocks:
  */
 #define CLOCK_SGI_CYCLE			10
+
+#ifdef __KERNEL__
+/* This clock is not exposed to user space */
+#define CLOCK_REALTIME_COS		15
+#endif
+
 #define MAX_CLOCKS			16
 #define CLOCKS_MASK			(CLOCK_REALTIME | CLOCK_MONOTONIC)
 #define CLOCKS_MONO			CLOCK_MONOTONIC

trunk/include/linux/timerfd.h

@@ -19,13 +19,14 @@
  * shared O_* flags.
  */
 #define TFD_TIMER_ABSTIME (1 << 0)
+#define TFD_TIMER_CANCELON_SET (1 << 1)
 #define TFD_CLOEXEC O_CLOEXEC
 #define TFD_NONBLOCK O_NONBLOCK
 
 #define TFD_SHARED_FCNTL_FLAGS (TFD_CLOEXEC | TFD_NONBLOCK)
 /* Flags for timerfd_create.  */
 #define TFD_CREATE_FLAGS TFD_SHARED_FCNTL_FLAGS
 /* Flags for timerfd_settime.  */
-#define TFD_SETTIME_FLAGS TFD_TIMER_ABSTIME
+#define TFD_SETTIME_FLAGS (TFD_TIMER_ABSTIME | TFD_TIMER_CANCELON_SET)
 
 #endif /* _LINUX_TIMERFD_H */

trunk/kernel/hrtimer.c

@@ -78,13 +78,19 @@ DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
 			.get_time = &ktime_get_boottime,
 			.resolution = KTIME_LOW_RES,
 		},
+		{
+			.index = CLOCK_REALTIME_COS,
+			.get_time = &ktime_get_real,
+			.resolution = KTIME_LOW_RES,
+		},
 	}
 };
 
 static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = {
 	[CLOCK_REALTIME]	= HRTIMER_BASE_REALTIME,
 	[CLOCK_MONOTONIC]	= HRTIMER_BASE_MONOTONIC,
 	[CLOCK_BOOTTIME]	= HRTIMER_BASE_BOOTTIME,
+	[CLOCK_REALTIME_COS]	= HRTIMER_BASE_REALTIME_COS,
 };
 
 static inline int hrtimer_clockid_to_base(clockid_t clock_id)
@@ -110,6 +116,7 @@ static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
 	base->clock_base[HRTIMER_BASE_REALTIME].softirq_time = xtim;
 	base->clock_base[HRTIMER_BASE_MONOTONIC].softirq_time = mono;
 	base->clock_base[HRTIMER_BASE_BOOTTIME].softirq_time = boot;
+	base->clock_base[HRTIMER_BASE_REALTIME_COS].softirq_time = xtim;
 }
 
 /*
@@ -479,6 +486,8 @@ static inline void debug_deactivate(struct hrtimer *timer)
 	trace_hrtimer_cancel(timer);
 }
 
+static void hrtimer_expire_cancelable(struct hrtimer_cpu_base *cpu_base);
+
 /* High resolution timer related functions */
 #ifdef CONFIG_HIGH_RES_TIMERS
 
@@ -715,9 +724,14 @@ static void retrigger_next_event(void *arg)
 	struct hrtimer_cpu_base *base = &__get_cpu_var(hrtimer_bases);
 	struct timespec realtime_offset, xtim, wtm, sleep;
 
-	if (!hrtimer_hres_active())
+	if (!hrtimer_hres_active()) {
+		raw_spin_lock(&base->lock);
+		hrtimer_expire_cancelable(base);
+		raw_spin_unlock(&base->lock);
 		return;
+	}
 
+	/* Optimized out for !HIGH_RES */
 	get_xtime_and_monotonic_and_sleep_offset(&xtim, &wtm, &sleep);
 	set_normalized_timespec(&realtime_offset, -wtm.tv_sec, -wtm.tv_nsec);
 
@@ -727,6 +741,10 @@ static void retrigger_next_event(void *arg)
 		timespec_to_ktime(realtime_offset);
 	base->clock_base[HRTIMER_BASE_BOOTTIME].offset =
 		timespec_to_ktime(sleep);
+	base->clock_base[HRTIMER_BASE_REALTIME_COS].offset =
+		timespec_to_ktime(realtime_offset);
+
+	hrtimer_expire_cancelable(base);
 
 	hrtimer_force_reprogram(base, 0);
 	raw_spin_unlock(&base->lock);
@@ -1222,6 +1240,22 @@ static void __run_hrtimer(struct hrtimer *timer, ktime_t *now)
 	timer->state &= ~HRTIMER_STATE_CALLBACK;
 }
 
+static void hrtimer_expire_cancelable(struct hrtimer_cpu_base *cpu_base)
+{
+	struct timerqueue_node *node;
+	struct hrtimer_clock_base *base;
+	ktime_t now = ktime_get_real();
+
+	base = &cpu_base->clock_base[HRTIMER_BASE_REALTIME_COS];
+
+	while ((node = timerqueue_getnext(&base->active))) {
+			struct hrtimer *timer;
+
+			timer = container_of(node, struct hrtimer, node);
+			__run_hrtimer(timer, &now);
+	}
+}
+
 #ifdef CONFIG_HIGH_RES_TIMERS
 
 /*

trunk/kernel/time/timekeeping.c

@@ -1098,6 +1098,21 @@ void get_xtime_and_monotonic_and_sleep_offset(struct timespec *xtim,
 	} while (read_seqretry(&xtime_lock, seq));
 }
 
+/**
+ * ktime_get_monotonic_offset() - get wall_to_monotonic in ktime_t format
+ */
+ktime_t ktime_get_monotonic_offset(void)
+{
+	unsigned long seq;
+	struct timespec wtom;
+
+	do {
+		seq = read_seqbegin(&xtime_lock);
+		wtom = wall_to_monotonic;
+	} while (read_seqretry(&xtime_lock, seq));
+	return timespec_to_ktime(wtom);
+}
+
 /**
  * xtime_update() - advances the timekeeping infrastructure
  * @ticks:	number of ticks, that have elapsed since the last call.