[CCID3]: Use function for RTT sampling

This replaces the existing occurrences of RTT sampling with
the use of the new function dccp_sample_rtt.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 11 insertions, 41 deletions

diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 35123c19a08..f4097ddf250 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -414,8 +414,7 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
         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);
 
@@ -457,18 +456,10 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
                  * 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
@@ -487,15 +478,15 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
                         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)
@@ -505,10 +496,10 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
                                                     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),
@@ -1025,8 +1016,7 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
         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);
@@ -1042,17 +1032,7 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
                         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;
diff --git a/net/dccp/ccids/ccid3.h b/net/dccp/ccids/ccid3.h
index 15776a88c09..8d31b389c19 100644
--- a/net/dccp/ccids/ccid3.h
+++ b/net/dccp/ccids/ccid3.h
@@ -51,16 +51,6 @@
 /* Parameter t_mbi from [RFC 3448, 4.3]: backoff interval in seconds */
 #define TFRC_T_MBI                 64
 
-/* What we think is a reasonable upper limit on RTT values */
-#define CCID3_SANE_RTT_MAX         ((suseconds_t)(4 * USEC_PER_SEC))
-
-#define CCID3_RTT_SANITY_CHECK(rtt)                     do {               \
-                if (rtt > CCID3_SANE_RTT_MAX) {                            \
-                        DCCP_CRIT("RTT (%d) too large, substituting %d",   \
-                                  (int)rtt, (int)CCID3_SANE_RTT_MAX);      \
-                        rtt = CCID3_SANE_RTT_MAX;                          \
-                }                                       } while (0)
-
 enum ccid3_options {
         TFRC_OPT_LOSS_EVENT_RATE = 192,
         TFRC_OPT_LOSS_INTERVALS  = 193,