s390/pai_crypto: replace atomic_t with refcount_t

The s390 PMU of PAI crypto 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>

diff --git a/arch/s390/kernel/perf_pai_crypto.c b/arch/s390/kernel/perf_pai_crypto.c
index a7b339c4fd7c9ed6046f0c7a06913846df223e5d..fe7d1774ded18439270efeb3eecd200cbcc8893c 100644 (file)
--- a/arch/s390/kernel/perf_pai_crypto.c
+++ b/arch/s390/kernel/perf_pai_crypto.c
@@ -36,7 +36,7 @@ struct paicrypt_map {
        unsigned long *page;            /* Page for CPU to store counters */
        struct pai_userdata *save;      /* Page to store no-zero counters */
        unsigned int active_events;     /* # of PAI crypto users */
-       unsigned int refcnt;            /* Reference count mapped buffers */
+       refcount_t refcnt;              /* Reference count mapped buffers */
        enum paievt_mode mode;          /* Type of event */
        struct perf_event *event;       /* Perf event for sampling */
 };
@@ -57,10 +57,11 @@ static void paicrypt_event_destroy(struct perf_event *event)
        static_branch_dec(&pai_key);
        mutex_lock(&pai_reserve_mutex);
        debug_sprintf_event(cfm_dbg, 5, "%s event %#llx cpu %d users %d"
-                           " mode %d refcnt %d\n", __func__,
+                           " mode %d refcnt %u\n", __func__,
                            event->attr.config, event->cpu,
-                           cpump->active_events, cpump->mode, cpump->refcnt);
-       if (!--cpump->refcnt) {
+                           cpump->active_events, cpump->mode,
+                           refcount_read(&cpump->refcnt));
+       if (refcount_dec_and_test(&cpump->refcnt)) {
                debug_sprintf_event(cfm_dbg, 4, "%s page %#lx save %p\n",
                                    __func__, (unsigned long)cpump->page,
                                    cpump->save);
@@ -149,8 +150,10 @@ static int paicrypt_busy(struct perf_event_attr *a, struct paicrypt_map *cpump)
        /* Allocate memory for counter page and counter extraction.
         * Only the first counting event has to allocate a page.
         */
-       if (cpump->page)
+       if (cpump->page) {
+               refcount_inc(&cpump->refcnt);
                goto unlock;
+       }
 
        rc = -ENOMEM;
        cpump->page = (unsigned long *)get_zeroed_page(GFP_KERNEL);
@@ -164,18 +167,18 @@ static int paicrypt_busy(struct perf_event_attr *a, struct paicrypt_map *cpump)
                goto unlock;
        }
        rc = 0;
+       refcount_set(&cpump->refcnt, 1);
 
 unlock:
        /* 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",
+                           " mode %d refcnt %u page %#lx save %p rc %d\n",
                            __func__, a->sample_period, cpump->active_events,
-                           cpump->mode, cpump->refcnt,
+                           cpump->mode, refcount_read(&cpump->refcnt),
                            (unsigned long)cpump->page, cpump->save, rc);
        mutex_unlock(&pai_reserve_mutex);
        return rc;