6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Thomas Richter <tmricht@xxxxxxxxxxxxx>
[ Upstream commit b286997e83dcf7b498329a66a8a22fc8a5bf50f0 ]
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 <sumanthk@xxxxxxxxxxxxx>
Signed-off-by: Thomas Richter <tmricht@xxxxxxxxxxxxx>
Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Stable-dep-of: e9f3af02f639 ("s390/pai: fix sampling event removal for PMU device driver")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/s390/kernel/perf_pai_crypto.c | 1 -
arch/s390/kernel/perf_pai_ext.c | 1 -
2 files changed, 2 deletions(-)
diff --git a/arch/s390/kernel/perf_pai_crypto.c b/arch/s390/kernel/perf_pai_crypto.c
index 4a4e914c283c8..0921cea849125 100644
--- a/arch/s390/kernel/perf_pai_crypto.c
+++ b/arch/s390/kernel/perf_pai_crypto.c
@@ -253,7 +253,6 @@ 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);
}
}
diff --git a/arch/s390/kernel/perf_pai_ext.c b/arch/s390/kernel/perf_pai_ext.c
index b5febe22d0546..ac32107167eac 100644
--- a/arch/s390/kernel/perf_pai_ext.c
+++ b/arch/s390/kernel/perf_pai_ext.c
@@ -327,7 +327,6 @@ 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)
--
2.43.0
