int64_t previous_leak;    /* timestamp of the last leak done */
 } ThrottleState;
 
+typedef enum {
+    THROTTLE_READ = 0,
+    THROTTLE_WRITE,
+    THROTTLE_MAX
+} ThrottleDirection;
+
 typedef struct ThrottleTimers {
-    QEMUTimer *timers[2];     /* timers used to do the throttling */
+    QEMUTimer *timers[THROTTLE_MAX];    /* timers used to do the throttling */
     QEMUClockType clock_type; /* the clock used */
 
     /* Callbacks */
-    QEMUTimerCB *read_timer_cb;
-    QEMUTimerCB *write_timer_cb;
+    QEMUTimerCB *timer_cb[THROTTLE_MAX];
     void *timer_opaque;
 } ThrottleTimers;
 
 
 void throttle_timers_attach_aio_context(ThrottleTimers *tt,
                                         AioContext *new_context)
 {
-    tt->timers[0] = aio_timer_new(new_context, tt->clock_type, SCALE_NS,
-                                  tt->read_timer_cb, tt->timer_opaque);
-    tt->timers[1] = aio_timer_new(new_context, tt->clock_type, SCALE_NS,
-                                  tt->write_timer_cb, tt->timer_opaque);
+    tt->timers[THROTTLE_READ] =
+        aio_timer_new(new_context, tt->clock_type, SCALE_NS,
+                      tt->timer_cb[THROTTLE_READ], tt->timer_opaque);
+    tt->timers[THROTTLE_WRITE] =
+        aio_timer_new(new_context, tt->clock_type, SCALE_NS,
+                      tt->timer_cb[THROTTLE_WRITE], tt->timer_opaque);
 }
 
 /*
     memset(tt, 0, sizeof(ThrottleTimers));
 
     tt->clock_type = clock_type;
-    tt->read_timer_cb = read_timer_cb;
-    tt->write_timer_cb = write_timer_cb;
+    tt->timer_cb[THROTTLE_READ] = read_timer_cb;
+    tt->timer_cb[THROTTLE_WRITE] = write_timer_cb;
     tt->timer_opaque = timer_opaque;
     throttle_timers_attach_aio_context(tt, aio_context);
 }
 {
     int i;
 
-    for (i = 0; i < 2; i++) {
+    for (i = 0; i < THROTTLE_MAX; i++) {
         throttle_timer_destroy(&tt->timers[i]);
     }
 }