s390/pai: initialize event count once at initialization

Event count value is initialized and set to zero in function
paicrypt_start().  This function is called once per CPU when an
event is started on that CPU. This leads to event count value
being set to zero as many times as there are online CPUs.
This is not necessary. The event count value is bound to the event
and it is sufficient to initialize the event counter once at
event creation time. This is done when the event structure
is dynamicly allocated with __GFP_ZERO flag. This sets
member count to zero.

Acked-by: Sumanth Korikkar <[email protected]>
Signed-off-by: Thomas Richter <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

Author: Thomas Richter

arch/s390/kernel/perf_pai_crypto.c

@@ -322,7 +322,6 @@ static void paicrypt_start(struct perf_event *event, int flags)
 	if (!event->hw.last_tag) {
 		event->hw.last_tag = 1;
 		sum = paicrypt_getall(event);		/* Get current value */
-		local64_set(&event->count, 0);
 		local64_set(&event->hw.prev_count, sum);
 	}
 }

arch/s390/kernel/perf_pai_ext.c

@@ -326,7 +326,6 @@ static void paiext_start(struct perf_event *event, int flags)
 	event->hw.last_tag = 1;
 	sum = paiext_getall(event);		/* Get current value */
 	local64_set(&event->hw.prev_count, sum);
-	local64_set(&event->count, 0);
 }
 
 static int paiext_add(struct perf_event *event, int flags)