X-Git-Url: https://git.liburcu.org/?a=blobdiff_plain;f=src%2Fcommon%2Fkernel-consumer%2Fkernel-consumer.c;h=8d7570d1736100f281471cf596314e475846ba9e;hb=a48ac75ad9dd8a6769a9cc3ba8365f7faa46f1de;hp=5334d13585842b0d63ab7f61d2b8cfa33e2b3b5e;hpb=074060e8e7d729d94e69ced71ed52b4a40c982c2;p=lttng-tools.git

diff --git a/src/common/kernel-consumer/kernel-consumer.c b/src/common/kernel-consumer/kernel-consumer.c
index 5334d1358..8d7570d17 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 +380,7 @@ static int lttng_kconsumer_snapshot_metadata(
 	metadata_stream = metadata_channel->metadata_stream;
 	assert(metadata_stream);
 
-	pthread_mutex_lock(&metadata_stream->lock);
+	metadata_stream->read_subbuffer_ops.lock(metadata_stream);
 	assert(metadata_channel->trace_chunk);
 	assert(metadata_stream->trace_chunk);
 
@@ -431,7 +435,7 @@ 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;
@@ -961,7 +965,6 @@ 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) {
 				int ret_snapshot;
 
@@ -989,7 +992,6 @@ error_streams_sent_nosignal:
 					ret_code = LTTCOMM_CONSUMERD_SNAPSHOT_FAILED;
 				}
 			}
-			pthread_mutex_unlock(&channel->lock);
 		}
 		health_code_update();