From a6e2fe17eba47681e82cdb9cfed5a67b57802a78 Mon Sep 17 00:00:00 2001
From: Yang Yingliang <yangyingliang@huawei.com>
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 <yangyingliang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
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;
}
--
2.34.1