[TCP]: cleanup of htcp (resend)

Minor non-invasive cleanups:
 * white space around operators and line wrapping
 * use const
 * use __read_mostly

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp_htcp.c b/net/ipv4/tcp_htcp.c
index 63318b6e9d512e139861eed32148488093c17a08..1020eb48d8d18590a0ae4da87fc8462bdb7fd60f 100644 (file)
--- a/net/ipv4/tcp_htcp.c
+++ b/net/ipv4/tcp_htcp.c
@@ -10,22 +10,23 @@
 #include <linux/module.h>
 #include <net/tcp.h>
 
-#define ALPHA_BASE     (1<<7)  /* 1.0 with shift << 7 */
-#define BETA_MIN       (1<<6)  /* 0.5 with shift << 7 */
+#define ALPHA_BASE     (1<<7)  /* 1.0 with shift << 7 */
+#define BETA_MIN       (1<<6)  /* 0.5 with shift << 7 */
 #define BETA_MAX       102     /* 0.8 with shift << 7 */
 
-static int use_rtt_scaling = 1;
+static int use_rtt_scaling __read_mostly = 1;
 module_param(use_rtt_scaling, int, 0644);
 MODULE_PARM_DESC(use_rtt_scaling, "turn on/off RTT scaling");
 
-static int use_bandwidth_switch = 1;
+static int use_bandwidth_switch __read_mostly = 1;
 module_param(use_bandwidth_switch, int, 0644);
 MODULE_PARM_DESC(use_bandwidth_switch, "turn on/off bandwidth switcher");
 
 struct htcp {
        u32     alpha;          /* Fixed point arith, << 7 */
        u8      beta;           /* Fixed point arith, << 7 */
-       u8      modeswitch;     /* Delay modeswitch until we had at least one congestion event */
+       u8      modeswitch;     /* Delay modeswitch
+                                  until we had at least one congestion event */
        u16     pkts_acked;
        u32     packetcount;
        u32     minRTT;
@@ -44,14 +45,14 @@ struct htcp {
        u32     lasttime;
 };
 
-static inline u32 htcp_cong_time(struct htcp *ca)
+static inline u32 htcp_cong_time(const struct htcp *ca)
 {
        return jiffies - ca->last_cong;
 }
 
-static inline u32 htcp_ccount(struct htcp *ca)
+static inline u32 htcp_ccount(const struct htcp *ca)
 {
-       return htcp_cong_time(ca)/ca->minRTT;
+       return htcp_cong_time(ca) / ca->minRTT;
 }
 
 static inline void htcp_reset(struct htcp *ca)
@@ -67,10 +68,12 @@ static u32 htcp_cwnd_undo(struct sock *sk)
 {
        const struct tcp_sock *tp = tcp_sk(sk);
        struct htcp *ca = inet_csk_ca(sk);
+
        ca->last_cong = ca->undo_last_cong;
        ca->maxRTT = ca->undo_maxRTT;
        ca->old_maxB = ca->undo_old_maxB;
-       return max(tp->snd_cwnd, (tp->snd_ssthresh<<7)/ca->beta);
+
+       return max(tp->snd_cwnd, (tp->snd_ssthresh << 7) / ca->beta);
 }
 
 static inline void measure_rtt(struct sock *sk)
@@ -78,17 +81,19 @@ static inline void measure_rtt(struct sock *sk)
        const struct inet_connection_sock *icsk = inet_csk(sk);
        const struct tcp_sock *tp = tcp_sk(sk);
        struct htcp *ca = inet_csk_ca(sk);
-       u32 srtt = tp->srtt>>3;
+       u32 srtt = tp->srtt >> 3;
 
        /* keep track of minimum RTT seen so far, minRTT is zero at first */
        if (ca->minRTT > srtt || !ca->minRTT)
                ca->minRTT = srtt;
 
        /* max RTT */
-       if (icsk->icsk_ca_state == TCP_CA_Open && tp->snd_ssthresh < 0xFFFF && htcp_ccount(ca) > 3) {
+       if (icsk->icsk_ca_state == TCP_CA_Open
+           && tp->snd_ssthresh < 0xFFFF && htcp_ccount(ca) > 3) {
                if (ca->maxRTT < ca->minRTT)
                        ca->maxRTT = ca->minRTT;
-               if (ca->maxRTT < srtt && srtt <= ca->maxRTT+msecs_to_jiffies(20))
+               if (ca->maxRTT < srtt
+                   && srtt <= ca->maxRTT + msecs_to_jiffies(20))
                        ca->maxRTT = srtt;
        }
 }
@@ -116,15 +121,16 @@ static void measure_achieved_throughput(struct sock *sk, u32 pkts_acked)
 
        ca->packetcount += pkts_acked;
 
-       if (ca->packetcount >= tp->snd_cwnd - (ca->alpha>>7? : 1)
-                       && now - ca->lasttime >= ca->minRTT
-                       && ca->minRTT > 0) {
-               __u32 cur_Bi = ca->packetcount*HZ/(now - ca->lasttime);
+       if (ca->packetcount >= tp->snd_cwnd - (ca->alpha >> 7 ? : 1)
+           && now - ca->lasttime >= ca->minRTT
+           && ca->minRTT > 0) {
+               __u32 cur_Bi = ca->packetcount * HZ / (now - ca->lasttime);
+
                if (htcp_ccount(ca) <= 3) {
                        /* just after backoff */
                        ca->minB = ca->maxB = ca->Bi = cur_Bi;
                } else {
-                       ca->Bi = (3*ca->Bi + cur_Bi)/4;
+                       ca->Bi = (3 * ca->Bi + cur_Bi) / 4;
                        if (ca->Bi > ca->maxB)
                                ca->maxB = ca->Bi;
                        if (ca->minB > ca->maxB)
@@ -142,7 +148,7 @@ static inline void htcp_beta_update(struct htcp *ca, u32 minRTT, u32 maxRTT)
                u32 old_maxB = ca->old_maxB;
                ca->old_maxB = ca->maxB;
 
-               if (!between(5*maxB, 4*old_maxB, 6*old_maxB)) {
+               if (!between(5 * maxB, 4 * old_maxB, 6 * old_maxB)) {
                        ca->beta = BETA_MIN;
                        ca->modeswitch = 0;
                        return;
@@ -150,7 +156,7 @@ static inline void htcp_beta_update(struct htcp *ca, u32 minRTT, u32 maxRTT)
        }
 
        if (ca->modeswitch && minRTT > msecs_to_jiffies(10) && maxRTT) {
-               ca->beta = (minRTT<<7)/maxRTT;
+               ca->beta = (minRTT << 7) / maxRTT;
                if (ca->beta < BETA_MIN)
                        ca->beta = BETA_MIN;
                else if (ca->beta > BETA_MAX)
@@ -169,23 +175,26 @@ static inline void htcp_alpha_update(struct htcp *ca)
 
        if (diff > HZ) {
                diff -= HZ;
-               factor = 1+ ( 10*diff + ((diff/2)*(diff/2)/HZ) )/HZ;
+               factor = 1 + (10 * diff + ((diff / 2) * (diff / 2) / HZ)) / HZ;
        }
 
        if (use_rtt_scaling && minRTT) {
-               u32 scale = (HZ<<3)/(10*minRTT);
-               scale = min(max(scale, 1U<<2), 10U<<3); /* clamping ratio to interval [0.5,10]<<3 */
-               factor = (factor<<3)/scale;
+               u32 scale = (HZ << 3) / (10 * minRTT);
+
+               /* clamping ratio to interval [0.5,10]<<3 */
+               scale = min(max(scale, 1U << 2), 10U << 3);
+               factor = (factor << 3) / scale;
                if (!factor)
                        factor = 1;
        }
 
-       ca->alpha = 2*factor*((1<<7)-ca->beta);
+       ca->alpha = 2 * factor * ((1 << 7) - ca->beta);
        if (!ca->alpha)
                ca->alpha = ALPHA_BASE;
 }
 
-/* After we have the rtt data to calculate beta, we'd still prefer to wait one
+/*
+ * After we have the rtt data to calculate beta, we'd still prefer to wait one
  * rtt before we adjust our beta to ensure we are working from a consistent
  * data.
  *
@@ -202,15 +211,16 @@ static void htcp_param_update(struct sock *sk)
        htcp_beta_update(ca, minRTT, maxRTT);
        htcp_alpha_update(ca);
 
-       /* add slowly fading memory for maxRTT to accommodate routing changes etc */
+       /* add slowly fading memory for maxRTT to accommodate routing changes */
        if (minRTT > 0 && maxRTT > minRTT)
-               ca->maxRTT = minRTT + ((maxRTT-minRTT)*95)/100;
+               ca->maxRTT = minRTT + ((maxRTT - minRTT) * 95) / 100;
 }
 
 static u32 htcp_recalc_ssthresh(struct sock *sk)
 {
        const struct tcp_sock *tp = tcp_sk(sk);
        const struct htcp *ca = inet_csk_ca(sk);
+
        htcp_param_update(sk);
        return max((tp->snd_cwnd * ca->beta) >> 7, 2U);
 }
@@ -227,7 +237,6 @@ static void htcp_cong_avoid(struct sock *sk, u32 ack, u32 rtt,
        if (tp->snd_cwnd <= tp->snd_ssthresh)
                tcp_slow_start(tp);
        else {
-
                measure_rtt(sk);
 
                /* In dangerous area, increase slowly.