[PATCH v4 4/6] timerfd: Move repeated logic into timerfd_rearm()

[Alexey Perevalov <a.perevalov@samsung.com>]

From: Anton Vorontsov <anton@enomsg.org>

This patch introduces timerfd_rearm(), this small helper is used to
forward and restart the hrtimer.

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Signed-off-by: Alexey Perevalov <a.perevalov@samsung.com>
---
 fs/timerfd.c |   40 +++++++++++++++++++---------------------
 1 file changed, 19 insertions(+), 21 deletions(-)

diff --git a/fs/timerfd.c b/fs/timerfd.c
index 9293121..4a349cb 100644
--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -229,6 +229,23 @@ static unsigned int timerfd_poll(struct file *file, poll_table *wait)
 	return events;
 }
 
+static u64 timerfd_rearm(struct timerfd_ctx *ctx)
+{
+	u64 orun = 0;
+
+	if (isalarm(ctx)) {
+		orun += alarm_forward_now(
+			&ctx->t.alarm, ctx->tintv) - 1;
+		alarm_restart(&ctx->t.alarm);
+	} else {
+		orun += hrtimer_forward_now(&ctx->t.tmr,
+		     ctx->tintv) - 1;
+		hrtimer_restart(&ctx->t.tmr);
+	}
+
+	return orun;
+}
+
 static ssize_t timerfd_read(struct file *file, char __user *buf, size_t count,
 			    loff_t *ppos)
 {
@@ -265,15 +282,7 @@ static ssize_t timerfd_read(struct file *file, char __user *buf, size_t count,
 			 * callback to avoid DoS attacks specifying a very
 			 * short timer period.
 			 */
-			if (isalarm(ctx)) {
-				ticks += alarm_forward_now(
-					&ctx->t.alarm, ctx->tintv) - 1;
-				alarm_restart(&ctx->t.alarm);
-			} else {
-				ticks += hrtimer_forward_now(&ctx->t.tmr,
-							     ctx->tintv) - 1;
-				hrtimer_restart(&ctx->t.tmr);
-			}
+			ticks += timerfd_rearm(ctx);
 		}
 		ctx->expired = 0;
 		ctx->ticks = 0;
@@ -421,18 +430,7 @@ static int do_timerfd_gettime(int ufd, struct itimerspec *t)
 	spin_lock_irq(&ctx->wqh.lock);
 	if (ctx->expired && ctx->tintv.tv64) {
 		ctx->expired = 0;
-
-		if (isalarm(ctx)) {
-			ctx->ticks +=
-				alarm_forward_now(
-					&ctx->t.alarm, ctx->tintv) - 1;
-			alarm_restart(&ctx->t.alarm);
-		} else {
-			ctx->ticks +=
-				hrtimer_forward_now(&ctx->t.tmr, ctx->tintv)
-				- 1;
-			hrtimer_restart(&ctx->t.tmr);
-		}
+		ctx->ticks += timerfd_rearm(ctx);
 	}
 	t->it_value = ktime_to_timespec(timerfd_get_remaining(ctx));
 	t->it_interval = ktime_to_timespec(ctx->tintv);
-- 
1.7.9.5