[PATCH] s390: cleanup timer API use

[PATCH] s390: cleanup timer API use

[Yu Liao]

cleanup the s390's use of the timer API
- del_timer() contains timer_pending() condition
- mod_timer(timer, expires) is equivalent to:

	del_timer(timer);
	timer->expires = expires;
	add_timer(timer);

If the timer is inactive it will be activated, using add_timer() on
condition !timer_pending(&private->timer) is redundant.

Just cleanup, no logic change.

Signed-off-by: Yu Liao <liaoyu15@huawei.com>
---
 drivers/s390/char/sclp.c       |  4 +---
 drivers/s390/char/sclp_con.c   |  3 +--
 drivers/s390/char/sclp_vt220.c |  6 ++----
 drivers/s390/cio/device_fsm.c  | 12 +++---------
 drivers/s390/cio/eadm_sch.c    | 12 +++---------
 5 files changed, 10 insertions(+), 27 deletions(-)

diff --git a/drivers/s390/char/sclp.c b/drivers/s390/char/sclp.c
index f0763e36b861..cb2491761958 100644
--- a/drivers/s390/char/sclp.c
+++ b/drivers/s390/char/sclp.c
@@ -745,9 +745,7 @@ sclp_sync_wait(void)
 	/* Loop until driver state indicates finished request */
 	while (sclp_running_state != sclp_running_state_idle) {
 		/* Check for expired request timer */
-		if (timer_pending(&sclp_request_timer) &&
-		    get_tod_clock_fast() > timeout &&
-		    del_timer(&sclp_request_timer))
+		if (get_tod_clock_fast() > timeout && del_timer(&sclp_request_timer))
 			sclp_request_timer.function(&sclp_request_timer);
 		cpu_relax();
 	}
diff --git a/drivers/s390/char/sclp_con.c b/drivers/s390/char/sclp_con.c
index de028868c6f4..fe5ee2646fcf 100644
--- a/drivers/s390/char/sclp_con.c
+++ b/drivers/s390/char/sclp_con.c
@@ -109,8 +109,7 @@ static void sclp_console_sync_queue(void)
 	unsigned long flags;
 
 	spin_lock_irqsave(&sclp_con_lock, flags);
-	if (timer_pending(&sclp_con_timer))
-		del_timer(&sclp_con_timer);
+	del_timer(&sclp_con_timer);
 	while (sclp_con_queue_running) {
 		spin_unlock_irqrestore(&sclp_con_lock, flags);
 		sclp_sync_wait();
diff --git a/drivers/s390/char/sclp_vt220.c b/drivers/s390/char/sclp_vt220.c
index 7bc4e4a10937..3b4e7e5d9b71 100644
--- a/drivers/s390/char/sclp_vt220.c
+++ b/drivers/s390/char/sclp_vt220.c
@@ -231,8 +231,7 @@ sclp_vt220_emit_current(void)
 			list_add_tail(&sclp_vt220_current_request->list,
 				      &sclp_vt220_outqueue);
 			sclp_vt220_current_request = NULL;
-			if (timer_pending(&sclp_vt220_timer))
-				del_timer(&sclp_vt220_timer);
+			del_timer(&sclp_vt220_timer);
 		}
 		sclp_vt220_flush_later = 0;
 	}
@@ -776,8 +775,7 @@ static void __sclp_vt220_flush_buffer(void)
 
 	sclp_vt220_emit_current();
 	spin_lock_irqsave(&sclp_vt220_lock, flags);
-	if (timer_pending(&sclp_vt220_timer))
-		del_timer(&sclp_vt220_timer);
+	del_timer(&sclp_vt220_timer);
 	while (sclp_vt220_queue_running) {
 		spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 		sclp_sync_wait();
diff --git a/drivers/s390/cio/device_fsm.c b/drivers/s390/cio/device_fsm.c
index 05e136cfb8be..6d63b968309a 100644
--- a/drivers/s390/cio/device_fsm.c
+++ b/drivers/s390/cio/device_fsm.c
@@ -113,16 +113,10 @@ ccw_device_timeout(struct timer_list *t)
 void
 ccw_device_set_timeout(struct ccw_device *cdev, int expires)
 {
-	if (expires == 0) {
+	if (expires == 0)
 		del_timer(&cdev->private->timer);
-		return;
-	}
-	if (timer_pending(&cdev->private->timer)) {
-		if (mod_timer(&cdev->private->timer, jiffies + expires))
-			return;
-	}
-	cdev->private->timer.expires = jiffies + expires;
-	add_timer(&cdev->private->timer);
+	else
+		mod_timer(&cdev->private->timer, jiffies + expires);
 }
 
 int
diff --git a/drivers/s390/cio/eadm_sch.c b/drivers/s390/cio/eadm_sch.c
index 8b463681a149..ab6a7495180a 100644
--- a/drivers/s390/cio/eadm_sch.c
+++ b/drivers/s390/cio/eadm_sch.c
@@ -112,16 +112,10 @@ static void eadm_subchannel_set_timeout(struct subchannel *sch, int expires)
 {
 	struct eadm_private *private = get_eadm_private(sch);
 
-	if (expires == 0) {
+	if (expires == 0)
 		del_timer(&private->timer);
-		return;
-	}
-	if (timer_pending(&private->timer)) {
-		if (mod_timer(&private->timer, jiffies + expires))
-			return;
-	}
-	private->timer.expires = jiffies + expires;
-	add_timer(&private->timer);
+	else
+		mod_timer(&private->timer, jiffies + expires);
 }
 
 static void eadm_subchannel_irq(struct subchannel *sch)
-- 
2.25.1

Re: [PATCH] s390: cleanup timer API use

[Heiko Carstens]

On Tue, Mar 22, 2022 at 11:00:57AM +0800, Yu Liao wrote:
> cleanup the s390's use of the timer API
> - del_timer() contains timer_pending() condition
> - mod_timer(timer, expires) is equivalent to:
> 
> 	del_timer(timer);
> 	timer->expires = expires;
> 	add_timer(timer);
> 
> If the timer is inactive it will be activated, using add_timer() on
> condition !timer_pending(&private->timer) is redundant.
> 
> Just cleanup, no logic change.
> 
> Signed-off-by: Yu Liao <liaoyu15@huawei.com>
> ---
>  drivers/s390/char/sclp.c       |  4 +---
>  drivers/s390/char/sclp_con.c   |  3 +--
>  drivers/s390/char/sclp_vt220.c |  6 ++----
>  drivers/s390/cio/device_fsm.c  | 12 +++---------
>  drivers/s390/cio/eadm_sch.c    | 12 +++---------
>  5 files changed, 10 insertions(+), 27 deletions(-)

Applied, thanks.