diff --git a/libs/ardour/ardour/disk_reader.h b/libs/ardour/ardour/disk_reader.h
index 64ee662e68..fd437e57ea 100644
--- a/libs/ardour/ardour/disk_reader.h
+++ b/libs/ardour/ardour/disk_reader.h
@@ -115,8 +115,6 @@ public:
 	static void reset_loop_declick (Location*, samplecnt_t sample_rate);
 	static void alloc_loop_declick (samplecnt_t sample_rate);
 
-	Glib::Threads::Mutex rbuf_lock;
-
 protected:
 	friend class Track;
 	friend class MidiTrack;
diff --git a/libs/ardour/disk_reader.cc b/libs/ardour/disk_reader.cc
index 22e035835a..e3cd75f5a1 100644
--- a/libs/ardour/disk_reader.cc
+++ b/libs/ardour/disk_reader.cc
@@ -78,8 +78,6 @@ DiskReader::~DiskReader ()
 void
 DiskReader::ReaderChannelInfo::resize (samplecnt_t bufsize)
 {
-	/* caller must hold rbuf lock */
-
 	delete rbuf; rbuf = 0;
 
 	rbuf = new PlaybackBuffer<Sample> (bufsize);
@@ -225,7 +223,6 @@ DiskReader::buffer_load () const
 void
 DiskReader::adjust_buffering ()
 {
-	Glib::Threads::Mutex::Lock lm (rbuf_lock);
 	boost::shared_ptr<ChannelList> c = channels.reader();
 
 	for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan) {