uhd: disabled atomic 'claim' check for multi-threaded access to recv_packet_demuxer_3000

The only caller is from super_packet_recv_handler, which is already not thread-safe.
The only underlying transport (libusb1_zero_copy) is thread-safe, so this shouldn't have an impact.
This solves the issue where (e.g. from GNU Radio), 'interrupt' is called on the worker thread while waiting for a join when worker thread is torn down (e.g. GR top block stop/wait/start),
which would cause the demuxer to still think the transport was claimed, as an interrupted exception will be thrown in 'wait_for_completion' in the transport, and execution will not
continue back into the demuxer to mark the transport as un-claimed, so future 'recv' streamer calls will always fail since the demux thinks the transport is still claimed from before.

1 files changed, 5 insertions, 1 deletions

diff --git a/host/lib/usrp/common/recv_packet_demuxer_3000.hpp b/host/lib/usrp/common/recv_packet_demuxer_3000.hpp
index 4fb6c4604..543c9ce76 100644
--- a/host/lib/usrp/common/recv_packet_demuxer_3000.hpp
+++ b/host/lib/usrp/common/recv_packet_demuxer_3000.hpp
@@ -70,7 +70,10 @@ namespace uhd{ namespace usrp{
                     return buff;
                 }
             }
-
+            // Following is disabled by default as super_recv_packet_handler (caller) is not thread safe
+            // Only underlying transport (libusb1_zero_copy) is thread safe
+            // The onus is on the caller to super_recv_packet_handler (and therefore this) to serialise access
+#ifdef RECV_PACKET_DEMUXER_3000_THREAD_SAFE
             //----------------------------------------------------------
             //-- Try to claim the transport or wait patiently
             //----------------------------------------------------------
@@ -84,6 +87,7 @@ namespace uhd{ namespace usrp{
             //-- Wait on the transport for input buffers
             //----------------------------------------------------------
             else
+#endif // RECV_PACKET_DEMUXER_3000_THREAD_SAFE
             {
                 buff = _xport->get_recv_buff(timeout);
                 if (buff)