4 files changed, 33 insertions, 35 deletions

diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index cd61dea2eea1..a1929f33d703 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -159,8 +159,8 @@ static void ccid3_hc_tx_update_x(struct sock *sk, ktime_t *stamp)
         } else if (ktime_us_delta(now, hctx->ccid3hctx_t_ld)
                                 - (s64)hctx->ccid3hctx_rtt >= 0) {
 
-                hctx->ccid3hctx_x =
-                        max(min(2 * hctx->ccid3hctx_x, min_rate),
+                hctx->ccid3hctx_x = min(2 * hctx->ccid3hctx_x, min_rate);
+                hctx->ccid3hctx_x = max(hctx->ccid3hctx_x,
                             scaled_div(((__u64)hctx->ccid3hctx_s) << 6,
                                        hctx->ccid3hctx_rtt));
                 hctx->ccid3hctx_t_ld = now;
@@ -193,22 +193,17 @@ static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len)
 
 /*
  *      Update Window Counter using the algorithm from [RFC 4342, 8.1].
- *      The algorithm is not applicable if RTT < 4 microseconds.
+ *      As elsewhere, RTT > 0 is assumed by using dccp_sample_rtt().
  */
 static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hctx,
                                                 ktime_t now)
 {
-        u32 quarter_rtts;
-
-        if (unlikely(hctx->ccid3hctx_rtt < 4))  /* avoid divide-by-zero */
-                return;
-
-        quarter_rtts = ktime_us_delta(now, hctx->ccid3hctx_t_last_win_count);
-        quarter_rtts /= hctx->ccid3hctx_rtt / 4;
+        u32 delta = ktime_us_delta(now, hctx->ccid3hctx_t_last_win_count),
+            quarter_rtts = (4 * delta) / hctx->ccid3hctx_rtt;
 
         if (quarter_rtts > 0) {
                 hctx->ccid3hctx_t_last_win_count = now;
-                hctx->ccid3hctx_last_win_count  += min_t(u32, quarter_rtts, 5);
+                hctx->ccid3hctx_last_win_count  += min(quarter_rtts, 5U);
                 hctx->ccid3hctx_last_win_count  &= 0xF;         /* mod 16 */
         }
 }
@@ -334,8 +329,14 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
                         hctx->ccid3hctx_x    = rfc3390_initial_rate(sk);
                         hctx->ccid3hctx_t_ld = now;
                 } else {
-                        /* Sender does not have RTT sample: X_pps = 1 pkt/sec */
-                        hctx->ccid3hctx_x = hctx->ccid3hctx_s;
+                        /*
+                         * Sender does not have RTT sample:
+                         * - set fallback RTT (RFC 4340, 3.4) since a RTT value
+                         *   is needed in several parts (e.g.  window counter);
+                         * - set sending rate X_pps = 1pps as per RFC 3448, 4.2.
+                         */
+                        hctx->ccid3hctx_rtt = DCCP_FALLBACK_RTT;
+                        hctx->ccid3hctx_x   = hctx->ccid3hctx_s;
                         hctx->ccid3hctx_x <<= 6;
                 }
                 ccid3_update_send_interval(hctx);
diff --git a/net/dccp/ccids/lib/tfrc.c b/net/dccp/ccids/lib/tfrc.c
index d1dfbb8de64c..97ecec0a8e76 100644
--- a/net/dccp/ccids/lib/tfrc.c
+++ b/net/dccp/ccids/lib/tfrc.c
@@ -14,14 +14,6 @@ module_param(tfrc_debug, bool, 0444);
 MODULE_PARM_DESC(tfrc_debug, "Enable debug messages");
 #endif
 
-extern int  tfrc_tx_packet_history_init(void);
-extern void tfrc_tx_packet_history_exit(void);
-extern int  tfrc_rx_packet_history_init(void);
-extern void tfrc_rx_packet_history_exit(void);
-
-extern int  tfrc_li_init(void);
-extern void tfrc_li_exit(void);
-
 static int __init tfrc_module_init(void)
 {
         int rc = tfrc_li_init();
diff --git a/net/dccp/ccids/lib/tfrc.h b/net/dccp/ccids/lib/tfrc.h
index 1fb1187bbf1c..ed9857527acf 100644
--- a/net/dccp/ccids/lib/tfrc.h
+++ b/net/dccp/ccids/lib/tfrc.h
@@ -15,7 +15,7 @@
  *  (at your option) any later version.
  */
 #include <linux/types.h>
-#include <asm/div64.h>
+#include <linux/math64.h>
 #include "../../dccp.h"
 /* internal includes that this module exports: */
 #include "loss_interval.h"
@@ -29,21 +29,19 @@ extern int tfrc_debug;
 #endif
 
 /* integer-arithmetic divisions of type (a * 1000000)/b */
-static inline u64 scaled_div(u64 a, u32 b)
+static inline u64 scaled_div(u64 a, u64 b)
 {
         BUG_ON(b==0);
-        a *= 1000000;
-        do_div(a, b);
-        return a;
+        return div64_u64(a * 1000000, b);
 }
 
-static inline u32 scaled_div32(u64 a, u32 b)
+static inline u32 scaled_div32(u64 a, u64 b)
 {
         u64 result = scaled_div(a, b);
 
         if (result > UINT_MAX) {
-                DCCP_CRIT("Overflow: a(%llu)/b(%u) > ~0U",
-                          (unsigned long long)a, b);
+                DCCP_CRIT("Overflow: %llu/%llu > UINT_MAX",
+                          (unsigned long long)a, (unsigned long long)b);
                 return UINT_MAX;
         }
         return result;
@@ -58,7 +56,14 @@ static inline u32 tfrc_ewma(const u32 avg, const u32 newval, const u8 weight)
         return avg ? (weight * avg + (10 - weight) * newval) / 10 : newval;
 }
 
-extern u32 tfrc_calc_x(u16 s, u32 R, u32 p);
-extern u32 tfrc_calc_x_reverse_lookup(u32 fvalue);
+extern u32  tfrc_calc_x(u16 s, u32 R, u32 p);
+extern u32  tfrc_calc_x_reverse_lookup(u32 fvalue);
 
+extern int  tfrc_tx_packet_history_init(void);
+extern void tfrc_tx_packet_history_exit(void);
+extern int  tfrc_rx_packet_history_init(void);
+extern void tfrc_rx_packet_history_exit(void);
+
+extern int  tfrc_li_init(void);
+extern void tfrc_li_exit(void);
 #endif /* _TFRC_H_ */
diff --git a/net/dccp/ccids/lib/tfrc_equation.c b/net/dccp/ccids/lib/tfrc_equation.c
index e4e64b76c10c..2f20a29cffe4 100644
--- a/net/dccp/ccids/lib/tfrc_equation.c
+++ b/net/dccp/ccids/lib/tfrc_equation.c
@@ -661,7 +661,7 @@ u32 tfrc_calc_x(u16 s, u32 R, u32 p)
 
 EXPORT_SYMBOL_GPL(tfrc_calc_x);
 
-/*
+/**
  *  tfrc_calc_x_reverse_lookup  -  try to find p given f(p)
  *
  *  @fvalue: function value to match, scaled by 1000000
@@ -676,11 +676,11 @@ u32 tfrc_calc_x_reverse_lookup(u32 fvalue)
 
         /* Error cases. */
         if (fvalue < tfrc_calc_x_lookup[0][1]) {
-                DCCP_WARN("fvalue %d smaller than resolution\n", fvalue);
-                return tfrc_calc_x_lookup[0][1];
+                DCCP_WARN("fvalue %u smaller than resolution\n", fvalue);
+                return TFRC_SMALLEST_P;
         }
         if (fvalue > tfrc_calc_x_lookup[TFRC_CALC_X_ARRSIZE - 1][0]) {
-                DCCP_WARN("fvalue %d exceeds bounds!\n", fvalue);
+                DCCP_WARN("fvalue %u exceeds bounds!\n", fvalue);
                 return 1000000;
         }