s390/zcrypt: fixed ap poll timer behavior

The ap poll timer restart condition was wrong. Hence the poll timer
was not restarted reliable when setting a new time interval via the
poll_timeout sysfs attribute.
Added missing timer locking.

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Tuchscherer <ingo.tuchscherer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 7 insertions, 9 deletions

diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c
index f0b9871a4bbd..6e506a88f43e 100644
--- a/drivers/s390/crypto/ap_bus.c
+++ b/drivers/s390/crypto/ap_bus.c
@@ -1158,11 +1158,12 @@ static ssize_t poll_timeout_store(struct bus_type *bus, const char *buf,
         poll_timeout = time;
         hr_time = ktime_set(0, poll_timeout);
 
-        if (!hrtimer_is_queued(&ap_poll_timer) ||
-            !hrtimer_forward(&ap_poll_timer, hrtimer_get_expires(&ap_poll_timer), hr_time)) {
-                hrtimer_set_expires(&ap_poll_timer, hr_time);
-                hrtimer_start_expires(&ap_poll_timer, HRTIMER_MODE_ABS);
-        }
+        spin_lock_bh(&ap_poll_timer_lock);
+        hrtimer_cancel(&ap_poll_timer);
+        hrtimer_set_expires(&ap_poll_timer, hr_time);
+        hrtimer_start_expires(&ap_poll_timer, HRTIMER_MODE_ABS);
+        spin_unlock_bh(&ap_poll_timer_lock);
+
         return count;
 }
 
@@ -1528,14 +1529,11 @@ static inline void __ap_schedule_poll_timer(void)
         ktime_t hr_time;
 
         spin_lock_bh(&ap_poll_timer_lock);
-        if (hrtimer_is_queued(&ap_poll_timer) || ap_suspend_flag)
-                goto out;
-        if (ktime_to_ns(hrtimer_expires_remaining(&ap_poll_timer)) <= 0) {
+        if (!hrtimer_is_queued(&ap_poll_timer) && !ap_suspend_flag) {
                 hr_time = ktime_set(0, poll_timeout);
                 hrtimer_forward_now(&ap_poll_timer, hr_time);
                 hrtimer_restart(&ap_poll_timer);
         }
-out:
         spin_unlock_bh(&ap_poll_timer_lock);
 }