6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Thomas Richter <tmricht@xxxxxxxxxxxxx>
[ Upstream commit d3db4ac3c761def3d3a8e5ea6d05d1636c44c2ba ]
Rework the mapped buffer reference count in PMU pai_crypto
to match the same technique as in PMU pai_ext.
This simplifies the logic.
Do not count the individual number of counter and sampling
processes. Remember the type of access and the total number of
references to the buffer.
Signed-off-by: Thomas Richter <tmricht@xxxxxxxxxxxxx>
Acked-by: Sumanth Korikkar <sumanthk@xxxxxxxxxxxxx>
Signed-off-by: Vasily Gorbik <gor@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_crypto.c | 42 ++++++++++++++----------------
1 file changed, 20 insertions(+), 22 deletions(-)
diff --git a/arch/s390/kernel/perf_pai_crypto.c b/arch/s390/kernel/perf_pai_crypto.c
index f61a652046cfb..68a6132937f3e 100644
--- a/arch/s390/kernel/perf_pai_crypto.c
+++ b/arch/s390/kernel/perf_pai_crypto.c
@@ -36,8 +36,8 @@ struct paicrypt_map {
unsigned long *page; /* Page for CPU to store counters */
struct pai_userdata *save; /* Page to store no-zero counters */
unsigned int users; /* # of PAI crypto users */
- unsigned int sampler; /* # of PAI crypto samplers */
- unsigned int counter; /* # of PAI crypto counters */
+ unsigned int refcnt; /* Reference count mapped buffers */
+ enum paievt_mode mode; /* Type of event */
struct perf_event *event; /* Perf event for sampling */
};
@@ -56,15 +56,11 @@ static void paicrypt_event_destroy(struct perf_event *event)
cpump->event = NULL;
static_branch_dec(&pai_key);
mutex_lock(&pai_reserve_mutex);
- if (event->attr.sample_period)
- cpump->sampler -= 1;
- else
- cpump->counter -= 1;
- debug_sprintf_event(cfm_dbg, 5, "%s event %#llx cpu %d"
- " sampler %d counter %d\n", __func__,
- event->attr.config, event->cpu, cpump->sampler,
- cpump->counter);
- if (!cpump->counter && !cpump->sampler) {
+ debug_sprintf_event(cfm_dbg, 5, "%s event %#llx cpu %d users %d"
+ " mode %d refcnt %d\n", __func__,
+ event->attr.config, event->cpu, cpump->users,
+ cpump->mode, cpump->refcnt);
+ if (!--cpump->refcnt) {
debug_sprintf_event(cfm_dbg, 4, "%s page %#lx save %p\n",
__func__, (unsigned long)cpump->page,
cpump->save);
@@ -72,6 +68,7 @@ static void paicrypt_event_destroy(struct perf_event *event)
cpump->page = NULL;
kvfree(cpump->save);
cpump->save = NULL;
+ cpump->mode = PAI_MODE_NONE;
}
mutex_unlock(&pai_reserve_mutex);
}
@@ -136,17 +133,14 @@ static u64 paicrypt_getall(struct perf_event *event)
*/
static int paicrypt_busy(struct perf_event_attr *a, struct paicrypt_map *cpump)
{
- unsigned int *use_ptr;
int rc = 0;
mutex_lock(&pai_reserve_mutex);
if (a->sample_period) { /* Sampling requested */
- use_ptr = &cpump->sampler;
- if (cpump->counter || cpump->sampler)
+ if (cpump->mode != PAI_MODE_NONE)
rc = -EBUSY; /* ... sampling/counting active */
} else { /* Counting requested */
- use_ptr = &cpump->counter;
- if (cpump->sampler)
+ if (cpump->mode == PAI_MODE_SAMPLING)
rc = -EBUSY; /* ... and sampling active */
}
if (rc)
@@ -172,12 +166,16 @@ static int paicrypt_busy(struct perf_event_attr *a, struct paicrypt_map *cpump)
rc = 0;
unlock:
- /* If rc is non-zero, do not increment counter/sampler. */
- if (!rc)
- *use_ptr += 1;
- debug_sprintf_event(cfm_dbg, 5, "%s sample_period %#llx sampler %d"
- " counter %d page %#lx save %p rc %d\n", __func__,
- a->sample_period, cpump->sampler, cpump->counter,
+ /* If rc is non-zero, do not set mode and reference count */
+ if (!rc) {
+ cpump->refcnt++;
+ cpump->mode = a->sample_period ? PAI_MODE_SAMPLING
+ : PAI_MODE_COUNTING;
+ }
+ debug_sprintf_event(cfm_dbg, 5, "%s sample_period %#llx users %d"
+ " mode %d refcnt %d page %#lx save %p rc %d\n",
+ __func__, a->sample_period, cpump->users,
+ cpump->mode, cpump->refcnt,
(unsigned long)cpump->page, cpump->save, rc);
mutex_unlock(&pai_reserve_mutex);
return rc;
--
2.43.0
