[S390] zcrypt: fix scheduling of hrtimer ap_poll_timer

Every time a request is enqueued or there is some work outstanding
from the ap_tasklet, the ap_poll_timer is scheduled again.
Unfortunately it was permanently called. It looked as if it was
started in the past and thus imediately expired.
This has been changed. First it is checked if the hrtimer is already
expired. Then the expiring time is forwarded and the timer restarted.

Signed-off-by: Felix Beck <felix.beck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c
index 727a809636d8..ed3dcdea7fe1 100644
--- a/drivers/s390/crypto/ap_bus.c
+++ b/drivers/s390/crypto/ap_bus.c
@@ -1145,12 +1145,17 @@ ap_config_timeout(unsigned long ptr)
  */
 static inline void ap_schedule_poll_timer(void)
 {
+        ktime_t hr_time;
         if (ap_using_interrupts() || ap_suspend_flag)
                 return;
         if (hrtimer_is_queued(&ap_poll_timer))
                 return;
-        hrtimer_start(&ap_poll_timer, ktime_set(0, poll_timeout),
-                      HRTIMER_MODE_ABS);
+        if (ktime_to_ns(hrtimer_expires_remaining(&ap_poll_timer)) <= 0) {
+                hr_time = ktime_set(0, poll_timeout);
+                hrtimer_forward_now(&ap_poll_timer, hr_time);
+                hrtimer_restart(&ap_poll_timer);
+        }
+        return;
 }
 
 /**