X-Git-Url: https://git.liburcu.org/?a=blobdiff_plain;f=src%2Fcommon%2Fkernel-consumer%2Fkernel-consumer.c;h=362cbd2dca61bde6f23a4375725b172b22f3bb70;hb=8aaed9e719995e6fdc4d87decd1252594d3d80e7;hp=245f4ee46ee552eb60c75b7ca17156ed7ebd8d71;hpb=c1c2a6a67147c81eadc7a9cf241e99d38b7cf1f9;p=lttng-tools.git

diff --git a/src/common/kernel-consumer/kernel-consumer.c b/src/common/kernel-consumer/kernel-consumer.c
index 245f4ee46..362cbd2dc 100644
--- a/src/common/kernel-consumer/kernel-consumer.c
+++ b/src/common/kernel-consumer/kernel-consumer.c
@@ -139,7 +139,7 @@ error:
 /*
  * Take a snapshot of all the stream of a channel
  * RCU read-side lock must be held across this function to ensure existence of
- * channel. The channel lock must be held by the caller.
+ * channel.
  *
  * Returns 0 on success, < 0 on error
  */
@@ -154,6 +154,9 @@ static int lttng_kconsumer_snapshot_channel(
 
 	DBG("Kernel consumer snapshot channel %" PRIu64, key);
 
+	/* Prevent channel modifications while we perform the snapshot.*/
+	pthread_mutex_lock(&channel->lock);
+
 	rcu_read_lock();
 
 	/* Splice is not supported yet for channel snapshot. */
@@ -347,13 +350,14 @@ end_unlock:
 	pthread_mutex_unlock(&stream->lock);
 end:
 	rcu_read_unlock();
+	pthread_mutex_unlock(&channel->lock);
 	return ret;
 }
 
 /*
  * Read the whole metadata available for a snapshot.
  * RCU read-side lock must be held across this function to ensure existence of
- * metadata_channel. The channel lock must be held by the caller.
+ * metadata_channel.
  *
  * Returns 0 on success, < 0 on error
  */
@@ -376,7 +380,8 @@ static int lttng_kconsumer_snapshot_metadata(
 	metadata_stream = metadata_channel->metadata_stream;
 	assert(metadata_stream);
 
-	pthread_mutex_lock(&metadata_stream->lock);
+	/* Take all the appropriate locks hehehe.*/
+	metadata_stream->read_subbuffer_ops.lock(metadata_stream);
 	assert(metadata_channel->trace_chunk);
 	assert(metadata_stream->trace_chunk);
 
@@ -431,7 +436,7 @@ static int lttng_kconsumer_snapshot_metadata(
 
 	ret = 0;
 error_snapshot:
-	pthread_mutex_unlock(&metadata_stream->lock);
+	metadata_stream->read_subbuffer_ops.unlock(metadata_stream);
 	cds_list_del(&metadata_stream->send_node);
 	consumer_stream_destroy(metadata_stream, NULL);
 	metadata_channel->metadata_stream = NULL;
@@ -935,7 +940,6 @@ error_streams_sent_nosignal:
 			ERR("Channel %" PRIu64 " not found", key);
 			ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 		} else {
-			pthread_mutex_lock(&channel->lock);
 			if (msg.u.snapshot_channel.metadata == 1) {
 				ret = lttng_kconsumer_snapshot_metadata(channel, key,
 						msg.u.snapshot_channel.pathname,
@@ -955,7 +959,6 @@ error_streams_sent_nosignal:
 					ret_code = LTTCOMM_CONSUMERD_SNAPSHOT_FAILED;
 				}
 			}
-			pthread_mutex_unlock(&channel->lock);
 		}
 		health_code_update();