struct dccp_tx_hist_entry *packet;
        struct timeval now;
        unsigned long t_nfb;
-       u32 pinv;
-       suseconds_t r_sample, t_elapsed;
+       u32 pinv, r_sample;
 
        BUG_ON(hctx == NULL);
 
                 * Calculate new round trip sample as per [RFC 3448, 4.3] by
                 *      R_sample  =  (now - t_recvdata) - t_elapsed
                 */
-               r_sample  = timeval_delta(&now, &packet->dccphtx_tstamp);
-               t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10;
+               r_sample = dccp_sample_rtt(sk, &now, &packet->dccphtx_tstamp);
 
-               DCCP_BUG_ON(r_sample < 0);
-               if (unlikely(r_sample <= t_elapsed))
-                       DCCP_WARN("WARNING: r_sample=%dus <= t_elapsed=%dus\n",
-                                 (int)r_sample, (int)t_elapsed);
-               else
-                       r_sample -= t_elapsed;
-               CCID3_RTT_SANITY_CHECK(r_sample);
-
-               /* Update RTT estimate by
+               /*
+                * Update RTT estimate by
                 * If (No feedback recv)
                 *    R = R_sample;
                 * Else
                        ccid3_update_send_interval(hctx);
 
                        ccid3_pr_debug("%s(%p), s=%u, MSS=%u, "
-                                      "R_sample=%dus, X=%u\n", dccp_role(sk),
+                                      "R_sample=%uus, X=%u\n", dccp_role(sk),
                                       sk, hctx->ccid3hctx_s,
-                                      dp->dccps_mss_cache, (int)r_sample,
+                                      dp->dccps_mss_cache, r_sample,
                                       (unsigned)(hctx->ccid3hctx_x >> 6));
 
                        ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
                } else {
                        hctx->ccid3hctx_rtt = (9 * hctx->ccid3hctx_rtt +
-                                                  (u32)r_sample) / 10;
+                                                  r_sample) / 10;
 
                        /* Update sending rate (step 4 of [RFC 3448, 4.3]) */
                        if (hctx->ccid3hctx_p > 0)
                                                    hctx->ccid3hctx_p);
                        ccid3_hc_tx_update_x(sk, &now);
 
-                       ccid3_pr_debug("%s(%p), RTT=%uus (sample=%dus), s=%u, "
+                       ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, "
                                       "p=%u, X_calc=%u, X_recv=%u, X=%u\n",
                                       dccp_role(sk),
-                                      sk, hctx->ccid3hctx_rtt, (int)r_sample,
+                                      sk, hctx->ccid3hctx_rtt, r_sample,
                                       hctx->ccid3hctx_s, hctx->ccid3hctx_p,
                                       hctx->ccid3hctx_x_calc,
                                       (unsigned)(hctx->ccid3hctx_x_recv >> 6),
        const struct dccp_options_received *opt_recv;
        struct dccp_rx_hist_entry *packet;
        struct timeval now;
-       u32 p_prev, rtt_prev;
-       suseconds_t r_sample, t_elapsed;
+       u32 p_prev, r_sample, rtt_prev;
        int loss, payload_size;
 
        BUG_ON(hcrx == NULL);
                        break;
                rtt_prev = hcrx->ccid3hcrx_rtt;
                dccp_timestamp(sk, &now);
-               timeval_sub_usecs(&now, opt_recv->dccpor_timestamp_echo * 10);
-               r_sample = timeval_usecs(&now);
-               t_elapsed = opt_recv->dccpor_elapsed_time * 10;
-
-               DCCP_BUG_ON(r_sample < 0);
-               if (unlikely(r_sample <= t_elapsed))
-                       DCCP_WARN("r_sample=%ldus, t_elapsed=%ldus\n",
-                                 (long)r_sample, (long)t_elapsed);
-               else
-                       r_sample -= t_elapsed;
-               CCID3_RTT_SANITY_CHECK(r_sample);
+               r_sample = dccp_sample_rtt(sk, &now, NULL);
 
                if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
                        hcrx->ccid3hcrx_rtt = r_sample;