SERVER-75725 Control TaskExecutorCursor's connection-pinning behavior with a server parameter and add appropriate testing. In this PR, we:

    - Remove the now-obsolete getCallbackHandle interface from TEC.
    - Hook up the TEC default pinConnection-parameter to the relevant server parameter
    - Add a new suite running all search tests with that server parameter enabled
    - Fix a small bug to ensure we use the SSL mode provided by the request in PCTE
    - Fix a small bug to appropriately handle the case where we can't acquire a stream from the transport layer

1 files changed, 4 insertions, 2 deletions

diff --git a/src/mongo/executor/network_interface_tl.h b/src/mongo/executor/network_interface_tl.h
index 52bbe07273a..880a8f46e21 100644
--- a/src/mongo/executor/network_interface_tl.h
+++ b/src/mongo/executor/network_interface_tl.h
@@ -395,8 +395,10 @@ private:
     std::unique_ptr<transport::TransportLayer> _ownedTransportLayer;
     transport::ReactorHandle _reactor;
 
-    mutable Mutex _mutex =
-        MONGO_MAKE_LATCH(HierarchicalAcquisitionLevel(3), "NetworkInterfaceTL::_mutex");
+    // TODO SERVER-75830: This Mutex used to be at hierarcichal acquisition level 3. We temporary
+    // removed the level because it is sometimes acquired as part of task-scheduling when
+    // lower-level mutexes (like the ConnectionPool's) are held.
+    mutable Mutex _mutex = MONGO_MAKE_LATCH("NetworkInterfaceTL::_mutex");
     const ConnectionPool::Options _connPoolOpts;
     std::unique_ptr<NetworkConnectionHook> _onConnectHook;
     std::shared_ptr<ConnectionPool> _pool;