xprtrdma: Support RPC/RDMA v2 reverse-direction replies

Adjust the backchannel ->send_request method to encode a v2 Reply
when the transport has negotiated RPC/RDMA protocol version two.

The backchannel Call handler does not look at the transport header,
so it is already prepared for handling reverse-direction
rdma2_call_inline header types.

This commit gives us equivalent functionality as RPC/RDMA v1. The
_external/_middle header types are left unsupported for now.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
1 file changed