From a6e2fe17eba47681e82cdb9cfed5a67b57802a78 Mon Sep 17 00:00:00 2001 From: Yang Yingliang Date: Sat, 18 Jan 2014 18:13:31 +0800 Subject: [PATCH] sch_netem: replace magic numbers with enumerate Replace some magic numbers which describe states of 4-state model loss generator with enumerate. Signed-off-by: Yang Yingliang Signed-off-by: David S. Miller --- net/sched/sch_netem.c | 47 ++++++++++++++++++++++++++----------------- 1 file changed, 28 insertions(+), 19 deletions(-) diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c index 3019c10d6c56..a2bfc371b44a 100644 --- a/net/sched/sch_netem.c +++ b/net/sched/sch_netem.c @@ -110,6 +110,13 @@ struct netem_sched_data { CLG_GILB_ELL, } loss_model; + enum { + TX_IN_GAP_PERIOD = 1, + TX_IN_BURST_PERIOD, + LOST_IN_GAP_PERIOD, + LOST_IN_BURST_PERIOD, + } _4_state_model; + /* Correlated Loss Generation models */ struct clgstate { /* state of the Markov chain */ @@ -205,43 +212,45 @@ static bool loss_4state(struct netem_sched_data *q) * probabilities outgoing from the current state, then decides the * next state and if the next packet has to be transmitted or lost. * The four states correspond to: - * 1 => successfully transmitted packets within a gap period - * 4 => isolated losses within a gap period - * 3 => lost packets within a burst period - * 2 => successfully transmitted packets within a burst period + * TX_IN_GAP_PERIOD => successfully transmitted packets within a gap period + * LOST_IN_BURST_PERIOD => isolated losses within a gap period + * LOST_IN_GAP_PERIOD => lost packets within a burst period + * TX_IN_GAP_PERIOD => successfully transmitted packets within a burst period */ switch (clg->state) { - case 1: + case TX_IN_GAP_PERIOD: if (rnd < clg->a4) { - clg->state = 4; + clg->state = LOST_IN_BURST_PERIOD; return true; } else if (clg->a4 < rnd && rnd < clg->a1 + clg->a4) { - clg->state = 3; + clg->state = LOST_IN_GAP_PERIOD; return true; - } else if (clg->a1 + clg->a4 < rnd) - clg->state = 1; + } else if (clg->a1 + clg->a4 < rnd) { + clg->state = TX_IN_GAP_PERIOD; + } break; - case 2: + case TX_IN_BURST_PERIOD: if (rnd < clg->a5) { - clg->state = 3; + clg->state = LOST_IN_GAP_PERIOD; return true; - } else - clg->state = 2; + } else { + clg->state = TX_IN_BURST_PERIOD; + } break; - case 3: + case LOST_IN_GAP_PERIOD: if (rnd < clg->a3) - clg->state = 2; + clg->state = TX_IN_BURST_PERIOD; else if (clg->a3 < rnd && rnd < clg->a2 + clg->a3) { - clg->state = 1; + clg->state = TX_IN_GAP_PERIOD; } else if (clg->a2 + clg->a3 < rnd) { - clg->state = 3; + clg->state = LOST_IN_GAP_PERIOD; return true; } break; - case 4: - clg->state = 1; + case LOST_IN_BURST_PERIOD: + clg->state = TX_IN_GAP_PERIOD; break; } -- 2.20.1