net: sched: sch_netem: Refactor code in 4-state loss generator

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: a6e2fe17eb ("sch_netem: replace magic numbers with enumerate")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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;
 	}