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s390/pai: fix sampling event removal for PMU device driver 

In case of a sampling event, the PAI PMU device drivers need a
reference to this event.  Currently to PMU device driver reference
is removed when a sampling event is destroyed. This may lead to
situations where the reference of the PMU device driver is removed
while being used by a different sampling event.
Reset the event reference pointer of the PMU device driver when
a sampling event is deleted and before the next one might be added.

Fixes: 39d62336f5 ("s390/pai: add support for cryptography counters")
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Thomas Richter 2024-02-29 15:00:28 +01:00 committed by Vasily Gorbik
parent c9c260681f
commit e9f3af02f6
2 changed files with 14 additions and 6 deletions
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10
arch/s390/kernel/perf_pai_crypto.c
View File

@ -90,7 +90,6 @@ static void paicrypt_event_destroy(struct perf_event *event)
event->cpu);
struct paicrypt_map *cpump = mp->mapptr;
cpump->event = NULL;
static_branch_dec(&pai_key);
mutex_lock(&pai_reserve_mutex);
debug_sprintf_event(cfm_dbg, 5, "%s event %#llx cpu %d users %d"
@ -356,10 +355,15 @@ static int paicrypt_add(struct perf_event *event, int flags)
static void paicrypt_stop(struct perf_event *event, int flags)
{
if (!event->attr.sample_period) /* Counting */
struct paicrypt_mapptr *mp = this_cpu_ptr(paicrypt_root.mapptr);
struct paicrypt_map *cpump = mp->mapptr;
if (!event->attr.sample_period) { /* Counting */
paicrypt_read(event);
else /* Sampling */
} else { /* Sampling */
perf_sched_cb_dec(event->pmu);
cpump->event = NULL;
}
event->hw.state = PERF_HES_STOPPED;
}

10
arch/s390/kernel/perf_pai_ext.c
View File

@ -122,7 +122,6 @@ static void paiext_event_destroy(struct perf_event *event)
free_page(PAI_SAVE_AREA(event));
mutex_lock(&paiext_reserve_mutex);
cpump->event = NULL;
if (refcount_dec_and_test(&cpump->refcnt)) /* Last reference gone */
paiext_free(mp);
paiext_root_free();
@ -362,10 +361,15 @@ static int paiext_add(struct perf_event *event, int flags)
static void paiext_stop(struct perf_event *event, int flags)
{
if (!event->attr.sample_period) /* Counting */
struct paiext_mapptr *mp = this_cpu_ptr(paiext_root.mapptr);
struct paiext_map *cpump = mp->mapptr;
if (!event->attr.sample_period) { /* Counting */
paiext_read(event);
else /* Sampling */
} else { /* Sampling */
perf_sched_cb_dec(event->pmu);
cpump->event = NULL;
}
event->hw.state = PERF_HES_STOPPED;
}