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>

1 files 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;
         }