UCP_OP_ATTR_FLAG_NO_IMM_CMPL breaks ucp_put_nbx()

[alex--m]

Looks like #7317 introduced a problem (in master), when UCP_OP_ATTR_FLAG_NO_IMM_CMPL is passed as the op_attr_mask. According to this code, in this case contig_length will be zero and no data will be sent...

The relevant code is copied from rma_send.c:

ucs_status_ptr_t ucp_put_nbx(ucp_ep_h ep, const void *buffer, size_t count,
                             uint64_t remote_addr, ucp_rkey_h rkey,
                             const ucp_request_param_t *param)
{
    ucp_worker_h worker     = ep->worker;
    size_t contig_length    = 0;
    ucp_datatype_t datatype = ucp_dt_make_contig(1);
    ucp_ep_rma_config_t *rma_config;
    ucs_status_ptr_t ret;
    ucs_status_t status;
    ucp_request_t *req;
    uint32_t attr_mask;

    UCP_RMA_CHECK_PTR(worker->context, buffer, count);
    UCP_WORKER_THREAD_CS_ENTER_CONDITIONAL(worker);

    ucs_trace_req("put_nbx buffer %p count %zu remote_addr %"PRIx64" rkey %p to %s cb %p",
                   buffer, count, remote_addr, rkey, ucp_ep_peer_name(ep),
                   (param->op_attr_mask & UCP_OP_ATTR_FIELD_CALLBACK) ?
                   param->cb.send : NULL);

    attr_mask = param->op_attr_mask &
                (UCP_OP_ATTR_FIELD_DATATYPE | UCP_OP_ATTR_FLAG_NO_IMM_CMPL);

    if (worker->context->config.ext.proto_enable) {
        status = ucp_put_send_short(ep, buffer, count, remote_addr, rkey, param);
        if (ucs_likely(status != UCS_ERR_NO_RESOURCE)) {
            ret = UCS_STATUS_PTR(status);
            goto out_unlock;
        }

        req = ucp_request_get_param(worker, param,
                                    {ret = UCS_STATUS_PTR(UCS_ERR_NO_MEMORY);
                                    goto out_unlock;});
        req->send.rma.rkey        = rkey;
        req->send.rma.remote_addr = remote_addr;

        if (ucs_likely(attr_mask == 0)) {
            contig_length = count;
        } else if (attr_mask & UCP_OP_ATTR_FIELD_DATATYPE) {
            datatype = param->datatype;
            if (UCP_DT_IS_CONTIG(datatype)) {
                contig_length = ucp_contig_dt_length(datatype, count);
            }
        }

@gleon99