Move to kernel style SPDX license identifiers

[lttng-ust.git] / liblttng-ust / event-notifier-notification.c

diff --git a/liblttng-ust/event-notifier-notification.c b/liblttng-ust/event-notifier-notification.c
index f1fb8adcbe427a554de8b44bd67f6175375a1f56..472479fd39817060136cda0b99590050f52bdf84 100644 (file)
--- a/liblttng-ust/event-notifier-notification.c
+++ b/liblttng-ust/event-notifier-notification.c
@@ -1,29 +1,15 @@
 /*
- * event-notifier-notification.c
+ * SPDX-License-Identifier: LGPL-2.1-only
  *
  * Copyright (C) 2020 Francis Deslauriers <francis.deslauriers@efficios.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; only
- * version 2.1 of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #define _LGPL_SOURCE
 
 #include <assert.h>
-#include <byteswap.h>
 #include <errno.h>
 #include <lttng/ust-events.h>
+#include <lttng/ust-endian.h>
 #include <usterr-signal-safe.h>
 
 #include "../libmsgpack/msgpack.h"
@@ -284,13 +270,26 @@ static void record_error(struct lttng_event_notifier *event_notifier)
 {
        struct lttng_event_notifier_group *event_notifier_group =
                        event_notifier->group;
+       struct lttng_counter *error_counter;
        size_t dimension_index[1];
        int ret;
 
+       error_counter = CMM_LOAD_SHARED(event_notifier_group->error_counter);
+       /*
+        * load-acquire paired with store-release orders creation of the
+        * error counter and setting error_counter_len before the
+        * error_counter is used.
+        * Currently a full memory barrier is used, which could be
+        * turned into acquire-release barriers.
+        */
+       cmm_smp_mb();
+       /* This group may not have an error counter attached to it. */
+       if (!error_counter)
+               return;
+
        dimension_index[0] = event_notifier->error_counter_index;
        ret = event_notifier_group->error_counter->ops->counter_add(
-                       event_notifier_group->error_counter->counter,
-                       dimension_index, 1);
+                       error_counter->counter, dimension_index, 1);
        if (ret)
                WARN_ON_ONCE(1);
 }
@@ -302,7 +301,7 @@ void notification_send(struct lttng_event_notifier_notification *notif,
        ssize_t ret;
        size_t content_len;
        int iovec_count = 1;
-       struct lttng_ust_event_notifier_notification ust_notif;
+       struct lttng_ust_event_notifier_notification ust_notif = {0};
        struct iovec iov[2];
 
        assert(notif);