[lttng-dev] [PATCH lttng-tools 1/2] Cleanup: use CMM accessors for consumer_quit variable

[Mathieu Desnoyers]

Use CMM_LOAD_SHARED and CMM_STORE_SHARED, which are strictly
equivalent to a volatile variable, in line with the rest of the
lttng-tools project.

Also move its declaration to a header, rather than having multiple
declarations in C files, now following our coding style.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
---
 src/common/consumer/consumer.c               | 10 +++++-----
 src/common/consumer/consumer.h               |  6 ++++++
 src/common/kernel-consumer/kernel-consumer.c |  1 -
 src/common/ust-consumer/ust-consumer.c       |  1 -
 4 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/src/common/consumer/consumer.c b/src/common/consumer/consumer.c
index d07e5b4..9834322 100644
--- a/src/common/consumer/consumer.c
+++ b/src/common/consumer/consumer.c
@@ -76,7 +76,7 @@ int data_consumption_paused;
  * Also updated by the signal handler (consumer_should_exit()). Read by the
  * polling threads.
  */
-volatile int consumer_quit;
+int consumer_quit;
 
 /*
  * Global hash table containing respectively metadata and data streams. The
@@ -1227,7 +1227,7 @@ void lttng_consumer_should_exit(struct lttng_consumer_local_data *ctx)
 {
 	ssize_t ret;
 
-	consumer_quit = 1;
+	CMM_STORE_SHARED(consumer_quit, 1);
 	ret = lttng_write(ctx->consumer_should_quit[1], "4", 1);
 	if (ret < 1) {
 		PERROR("write consumer quit");
@@ -2526,7 +2526,7 @@ void *consumer_thread_data_poll(void *data)
 		pthread_mutex_unlock(&consumer_data.lock);
 
 		/* No FDs and consumer_quit, consumer_cleanup the thread */
-		if (nb_fd == 0 && consumer_quit == 1) {
+		if (nb_fd == 0 && CMM_LOAD_SHARED(consumer_quit) == 1) {
 			err = 0;	/* All is OK */
 			goto end;
 		}
@@ -3203,7 +3203,7 @@ void *consumer_thread_sessiond_poll(void *data)
 			err = 0;
 			goto end;
 		}
-		if (consumer_quit) {
+		if (CMM_LOAD_SHARED(consumer_quit)) {
 			DBG("consumer_thread_receive_fds received quit from signal");
 			err = 0;	/* All is OK */
 			goto end;
@@ -3228,7 +3228,7 @@ end:
 	 * when all fds have hung up, the polling thread
 	 * can exit cleanly
 	 */
-	consumer_quit = 1;
+	CMM_STORE_SHARED(consumer_quit, 1);
 
 	/*
 	 * Notify the data poll thread to poll back again and test the
diff --git a/src/common/consumer/consumer.h b/src/common/consumer/consumer.h
index 7375373..220dbb4 100644
--- a/src/common/consumer/consumer.h
+++ b/src/common/consumer/consumer.h
@@ -604,6 +604,12 @@ struct lttng_consumer_global_data {
 	struct lttng_ht *stream_per_chan_id_ht;
 };
 
+/*
+ * Set to nonzero when the consumer is exiting. Updated by signal
+ * handler and thread exit, read by threads.
+ */
+extern int consumer_quit;
+
 /* Flag used to temporarily pause data consumption from testpoints. */
 extern int data_consumption_paused;
 
diff --git a/src/common/kernel-consumer/kernel-consumer.c b/src/common/kernel-consumer/kernel-consumer.c
index b5afc73..8d00a0d 100644
--- a/src/common/kernel-consumer/kernel-consumer.c
+++ b/src/common/kernel-consumer/kernel-consumer.c
@@ -48,7 +48,6 @@
 
 extern struct lttng_consumer_global_data consumer_data;
 extern int consumer_poll_timeout;
-extern volatile int consumer_quit;
 
 /*
  * Take a snapshot for a specific fd
diff --git a/src/common/ust-consumer/ust-consumer.c b/src/common/ust-consumer/ust-consumer.c
index 99803a6..4297d60 100644
--- a/src/common/ust-consumer/ust-consumer.c
+++ b/src/common/ust-consumer/ust-consumer.c
@@ -51,7 +51,6 @@
 
 extern struct lttng_consumer_global_data consumer_data;
 extern int consumer_poll_timeout;
-extern volatile int consumer_quit;
 
 /*
  * Free channel object and all streams associated with it. This MUST be used
-- 
2.1.4