From 1ce357cb825f184519cf1d3c2b01581a0b97663c Mon Sep 17 00:00:00 2001
From: Thomas Richter <tmricht@linux.ibm.com>
Date: Tue, 24 Jan 2023 12:20:50 +0100
Subject: [PATCH] s390/cpum_cf: simplify hw_perf_event_destroy()
To remove an event from the CPU Measurement counter facility
use the lock/unlock scheme as done in event creation. Remove
the atomic_add_unless function to make the code easier.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
---
arch/s390/kernel/perf_cpum_cf.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/arch/s390/kernel/perf_cpum_cf.c b/arch/s390/kernel/perf_cpum_cf.c
index 28fa80fd69fa0..e58e49488ad9a 100644
--- a/arch/s390/kernel/perf_cpum_cf.c
+++ b/arch/s390/kernel/perf_cpum_cf.c
@@ -397,12 +397,10 @@ static DEFINE_MUTEX(pmc_reserve_mutex);
/* Release the PMU if event is the last perf event */
static void hw_perf_event_destroy(struct perf_event *event)
{
- if (!atomic_add_unless(&num_events, -1, 1)) {
- mutex_lock(&pmc_reserve_mutex);
- if (atomic_dec_return(&num_events) == 0)
- __kernel_cpumcf_end();
- mutex_unlock(&pmc_reserve_mutex);
- }
+ mutex_lock(&pmc_reserve_mutex);
+ if (atomic_dec_return(&num_events) == 0)
+ __kernel_cpumcf_end();
+ mutex_unlock(&pmc_reserve_mutex);
}
/* CPUMF <-> perf event mappings for kernel+userspace (basic set) */
--
2.30.2