From: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Date: Thu, 23 Dec 2010 16:58:04 +0000 (-0500)
Subject: Add session active test
X-Git-Tag: v2.0-pre1~180
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=52fc2e1ff4b6e6a1050bc211ff32a6ccb977d7a4;p=lttng-modules.git

Add session active test

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/ltt-events.c b/ltt-events.c
index c2a6a920..947d772c 100644
--- a/ltt-events.c
+++ b/ltt-events.c
@@ -49,7 +49,7 @@ void ltt_session_destroy(struct ltt_session *session)
 	int ret;
 
 	mutex_lock(&sessions_mutex);
-	session->active = 0;
+	ACCESS_ONCE(session->active) = 0;
 	list_for_each_entry(event, &session->events, list) {
 		ret = _ltt_event_unregister(event);
 		WARN_ON(ret);
@@ -73,7 +73,7 @@ int ltt_session_start(struct ltt_session *session)
 		ret = -EBUSY;
 		goto end;
 	}
-	session->active = 1;
+	ACCESS_ONCE(session->active) = 1;
 	synchronize_trace();	/* Wait for in-flight events to complete */
 end:
 	mutex_unlock(&sessions_mutex);
@@ -89,7 +89,7 @@ int ltt_session_stop(struct ltt_session *session)
 		ret = -EBUSY;
 		goto end;
 	}
-	session->active = 0;
+	ACCESS_ONCE(session->active) = 0;
 	synchronize_trace();	/* Wait for in-flight events to complete */
 end:
 	mutex_unlock(&sessions_mutex);
diff --git a/probes/lttng-events.h b/probes/lttng-events.h
index ee7e5d96..a05c29d5 100644
--- a/probes/lttng-events.h
+++ b/probes/lttng-events.h
@@ -514,6 +514,8 @@ static void __event_probe__##_name(void *__data, _proto)		      \
 									      \
 	if (0)								      \
 		(void) __dynamic_len_idx;	/* don't warn if unused */    \
+	if (!ACCESS_ONCE(__chan->session->active))			      \
+		return;							      \
 	__event_len = __event_get_size__##_name(__dynamic_len, _args);	      \
 	__event_align = __event_get_align__##_name(_args);		      \
 	lib_ring_buffer_ctx_init(&ctx, __chan->chan, NULL, __event_len,	      \