For a queue per xprt, there is no need for a patch to ntirpc.
Every transport calls back to nfs-ganesha via the xp_dispatch vector.
These all run MainNFSD/nfs_rpc_dispatcher_thread.c
nfs_rpc_tcp_user_data().
Therefore, for experimentation purposes, add one line immediately
before the return (line 1239):
+ newxprt->xp_ifindex = newxprt->xp_fd;
KISS.