6.1-stable review patch. If anyone has any objections, please let me know.
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From: Thomas Richter tmricht@linux.ibm.com
[ 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@linux.ibm.com Acked-by: Sumanth Korikkar sumanthk@linux.ibm.com Signed-off-by: Alexander Gordeev agordeev@linux.ibm.com Stable-dep-of: e9f3af02f639 ("s390/pai: fix sampling event removal for PMU device driver") Signed-off-by: Sasha Levin sashal@kernel.org --- 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;