6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Thomas Richter <tmricht@xxxxxxxxxxxxx>
[ Upstream commit 1f2597cd3686955a4d64e01909dbfe625a2a35a1 ]
The s390 PMU of PAI extension 1 NNPA counters uses atomic_t for
reference counting. Replace this with the proper data type
refcount_t.
No functional change.
Signed-off-by: Thomas Richter <tmricht@xxxxxxxxxxxxx>
Acked-by: Sumanth Korikkar <sumanthk@xxxxxxxxxxxxx>
Signed-off-by: Alexander Gordeev <agordeev@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_ext.c | 23 +++++++++++++----------
1 file changed, 13 insertions(+), 10 deletions(-)
diff --git a/arch/s390/kernel/perf_pai_ext.c b/arch/s390/kernel/perf_pai_ext.c
index b4d89654183a2..d6bc919530143 100644
--- a/arch/s390/kernel/perf_pai_ext.c
+++ b/arch/s390/kernel/perf_pai_ext.c
@@ -56,7 +56,7 @@ struct paiext_map {
struct pai_userdata *save; /* Area to store non-zero counters */
enum paiext_mode mode; /* Type of event */
unsigned int active_events; /* # of PAI Extension users */
- unsigned int refcnt;
+ refcount_t refcnt;
struct perf_event *event; /* Perf event for sampling */
struct paiext_cb *paiext_cb; /* PAI extension control block area */
};
@@ -66,14 +66,14 @@ struct paiext_mapptr {
};
static struct paiext_root { /* Anchor to per CPU data */
- int refcnt; /* Overall active events */
+ refcount_t refcnt; /* Overall active events */
struct paiext_mapptr __percpu *mapptr;
} paiext_root;
/* Free per CPU data when the last event is removed. */
static void paiext_root_free(void)
{
- if (!--paiext_root.refcnt) {
+ if (refcount_dec_and_test(&paiext_root.refcnt)) {
free_percpu(paiext_root.mapptr);
paiext_root.mapptr = NULL;
}
@@ -86,7 +86,7 @@ static void paiext_root_free(void)
*/
static int paiext_root_alloc(void)
{
- if (++paiext_root.refcnt == 1) {
+ if (!refcount_inc_not_zero(&paiext_root.refcnt)) {
/* The memory is already zeroed. */
paiext_root.mapptr = alloc_percpu(struct paiext_mapptr);
if (!paiext_root.mapptr) {
@@ -97,6 +97,7 @@ static int paiext_root_alloc(void)
*/
return -ENOMEM;
}
+ refcount_set(&paiext_root.refcnt, 1);
}
return 0;
}
@@ -128,7 +129,7 @@ static void paiext_event_destroy(struct perf_event *event)
mutex_lock(&paiext_reserve_mutex);
cpump->event = NULL;
- if (!--cpump->refcnt) /* Last reference gone */
+ if (refcount_dec_and_test(&cpump->refcnt)) /* Last reference gone */
paiext_free(mp);
paiext_root_free();
mutex_unlock(&paiext_reserve_mutex);
@@ -169,7 +170,7 @@ static int paiext_alloc(struct perf_event_attr *a, struct perf_event *event)
rc = -ENOMEM;
cpump = kzalloc(sizeof(*cpump), GFP_KERNEL);
if (!cpump)
- goto unlock;
+ goto undo;
/* Allocate memory for counter area and counter extraction.
* These are
@@ -189,8 +190,9 @@ static int paiext_alloc(struct perf_event_attr *a, struct perf_event *event)
GFP_KERNEL);
if (!cpump->save || !cpump->area || !cpump->paiext_cb) {
paiext_free(mp);
- goto unlock;
+ goto undo;
}
+ refcount_set(&cpump->refcnt, 1);
cpump->mode = a->sample_period ? PAI_MODE_SAMPLING
: PAI_MODE_COUNTER;
} else {
@@ -201,15 +203,15 @@ static int paiext_alloc(struct perf_event_attr *a, struct perf_event *event)
if (cpump->mode == PAI_MODE_SAMPLING ||
(cpump->mode == PAI_MODE_COUNTER && a->sample_period)) {
rc = -EBUSY;
- goto unlock;
+ goto undo;
}
+ refcount_inc(&cpump->refcnt);
}
rc = 0;
cpump->event = event;
- ++cpump->refcnt;
-unlock:
+undo:
if (rc) {
/* Error in allocation of event, decrement anchor. Since
* the event in not created, its destroy() function is never
@@ -217,6 +219,7 @@ static int paiext_alloc(struct perf_event_attr *a, struct perf_event *event)
*/
paiext_root_free();
}
+unlock:
mutex_unlock(&paiext_reserve_mutex);
/* If rc is non-zero, no increment of counter/sampler was done. */
return rc;
--
2.43.0
