timerfd: Use ktime_mono_to_real()

We have a few other use cases of ktime_get_monotonic_offset() which
can be optimized with ktime_mono_to_real(). The timerfd code uses the
offset only for comparison, so we can use ktime_mono_to_real(0) for
this as well.

Funny enough text size shrinks with that on ARM and x8664 !?
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>

fs/timerfd.c

@@ -93,7 +93,7 @@ static enum alarmtimer_restart timerfd_alarmproc(struct alarm *alarm,
  */
 void timerfd_clock_was_set(void)
 {
-	ktime_t moffs = ktime_get_monotonic_offset();
+	ktime_t moffs = ktime_mono_to_real((ktime_t){ .tv64 = 0 });
 	struct timerfd_ctx *ctx;
 	unsigned long flags;
 
@@ -126,7 +126,7 @@ static bool timerfd_canceled(struct timerfd_ctx *ctx)
 {
 	if (!ctx->might_cancel || ctx->moffs.tv64 != KTIME_MAX)
 		return false;
-	ctx->moffs = ktime_get_monotonic_offset();
+	ctx->moffs = ktime_mono_to_real((ktime_t){ .tv64 = 0 });
 	return true;
 }
 
@@ -405,7 +405,7 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags)
 	else
 		hrtimer_init(&ctx->t.tmr, clockid, HRTIMER_MODE_ABS);
 
-	ctx->moffs = ktime_get_monotonic_offset();
+	ctx->moffs = ktime_mono_to_real((ktime_t){ .tv64 = 0 });
 
 	ufd = anon_inode_getfd("[timerfd]", &timerfd_fops, ctx,
 			       O_RDWR | (flags & TFD_SHARED_FCNTL_FLAGS));