[PATCH v2] net: sched: sch_netem: Refactor code in 4-state loss generator

From: Harshit Mogalapalli
Date: Fri Nov 12 2021 - 16:37:12 EST


Fixed comments to match description with variable names and
refactored code to match the convention as per [1].

To match the convention mapping is done as follows:
State 3 - LOST_IN_BURST_PERIOD
State 4 - LOST_IN_GAP_PERIOD

[1] S. Salsano, F. Ludovici, A. Ordine, "Definition of a general
and intuitive loss model for packet networks and its implementation
in the Netem module in the Linux kernel"

Fixes: a6e2fe17eba4 ("sch_netem: replace magic numbers with enumerate")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@xxxxxxxxxx>
---
net/sched/sch_netem.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index ecbb10db1111..ed4ccef5d6a8 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -208,17 +208,17 @@ static bool loss_4state(struct netem_sched_data *q)
* next state and if the next packet has to be transmitted or lost.
* The four states correspond to:
* 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
+ * LOST_IN_GAP_PERIOD => isolated losses within a gap period
+ * LOST_IN_BURST_PERIOD => lost packets within a burst period
+ * TX_IN_BURST_PERIOD => successfully transmitted packets within a burst period
*/
switch (clg->state) {
case TX_IN_GAP_PERIOD:
if (rnd < clg->a4) {
- clg->state = LOST_IN_BURST_PERIOD;
+ clg->state = LOST_IN_GAP_PERIOD;
return true;
} else if (clg->a4 < rnd && rnd < clg->a1 + clg->a4) {
- clg->state = LOST_IN_GAP_PERIOD;
+ clg->state = LOST_IN_BURST_PERIOD;
return true;
} else if (clg->a1 + clg->a4 < rnd) {
clg->state = TX_IN_GAP_PERIOD;
@@ -227,24 +227,24 @@ static bool loss_4state(struct netem_sched_data *q)
break;
case TX_IN_BURST_PERIOD:
if (rnd < clg->a5) {
- clg->state = LOST_IN_GAP_PERIOD;
+ clg->state = LOST_IN_BURST_PERIOD;
return true;
} else {
clg->state = TX_IN_BURST_PERIOD;
}

break;
- case LOST_IN_GAP_PERIOD:
+ case LOST_IN_BURST_PERIOD:
if (rnd < clg->a3)
clg->state = TX_IN_BURST_PERIOD;
else if (clg->a3 < rnd && rnd < clg->a2 + clg->a3) {
clg->state = TX_IN_GAP_PERIOD;
} else if (clg->a2 + clg->a3 < rnd) {
- clg->state = LOST_IN_GAP_PERIOD;
+ clg->state = LOST_IN_BURST_PERIOD;
return true;
}
break;
- case LOST_IN_BURST_PERIOD:
+ case LOST_IN_GAP_PERIOD:
clg->state = TX_IN_GAP_PERIOD;
break;
}
--
2.27.0