Commit 8a6fe8f2 authored by Thomas Richter's avatar Thomas Richter Committed by Vasily Gorbik
Browse files

s390/cpum_sf: Use refcount_t instead of atomic_t 



Replace atomic_t by refcount_t for reference counting of events.

Signed-off-by: default avatarThomas Richter <tmricht@linux.ibm.com>
Acked-by: default avatarSumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent de9c2c66

arch/s390/kernel/perf_cpum_sf.c

+12 −17
Original line number Diff line number Diff line
@@ -585,7 +585,7 @@ static void extend_sampling_buffer(struct sf_buffer *sfb, 
}



/* Number of perf events counting hardware events */

static atomic_t num_events;

static refcount_t num_events;

/* Used to avoid races in calling reserve/release_cpumf_hardware */

static DEFINE_MUTEX(pmc_reserve_mutex);
@@ -644,9 +644,7 @@ static int reserve_pmc_hardware(void) 
static void hw_perf_event_destroy(struct perf_event *event)

{

	/* Release PMC if this is the last perf event */

	if (!atomic_add_unless(&num_events, -1, 1)) {

		mutex_lock(&pmc_reserve_mutex);

		if (atomic_dec_return(&num_events) == 0)

	if (refcount_dec_and_mutex_lock(&num_events, &pmc_reserve_mutex)) {

		release_pmc_hardware();

		mutex_unlock(&pmc_reserve_mutex);

	}
@@ -810,22 +808,19 @@ static int __hw_perf_event_init(struct perf_event *event) 
	struct hws_qsi_info_block si;

	struct perf_event_attr *attr = &event->attr;

	struct hw_perf_event *hwc = &event->hw;

	int cpu, err;

	int cpu, err = 0;



	/* Reserve CPU-measurement sampling facility */

	err = 0;

	if (!atomic_inc_not_zero(&num_events)) {

	mutex_lock(&pmc_reserve_mutex);

		if (atomic_read(&num_events) == 0 && reserve_pmc_hardware())

			err = -EBUSY;

		else

			atomic_inc(&num_events);

		mutex_unlock(&pmc_reserve_mutex);

	if (!refcount_inc_not_zero(&num_events)) {

		err = reserve_pmc_hardware();

		if (!err)

			refcount_set(&num_events, 1);

	}

	event->destroy = hw_perf_event_destroy;



	mutex_unlock(&pmc_reserve_mutex);

	if (err)

		goto out;

	event->destroy = hw_perf_event_destroy;



	/* Access per-CPU sampling information (query sampling info) */

	/*
@@ -2143,7 +2138,7 @@ static int cpusf_pmu_setup(unsigned int cpu, int flags) 
	/* Ignore the notification if no events are scheduled on the PMU.

	 * This might be racy...

	 */

	if (!atomic_read(&num_events))

	if (!refcount_read(&num_events))

		return 0;



	local_irq_disable();