contrib/package/olsrd-luci/patches/100-olsrd-timer-fix.patch

   1
   2 --- a/src/scheduler.c   Mon Aug 25 20:23:24 2008 +0200
   3 +++ b/src/scheduler.c   Mon Aug 25 23:02:29 2008 +0200
   4 @@ -63,7 +63,6 @@ clock_t now_times;                   /* current id
   5  /* Hashed root of all timers */
   6  struct list_node timer_wheel[TIMER_WHEEL_SLOTS];
   7  clock_t timer_last_run;                       /* remember the last timeslot walk */
   8 -struct list_node *timer_walk_list_node = NULL; /* used for timeslot walk */
   9
  10  /* Pool of timers to avoid malloc() churn */
  11  struct list_node free_timer_list;
  12 @@ -317,6 +316,35 @@ olsr_init_timers(void)
  13    timers_running = 0;
  14  }
  15
  16 +/*
  17 + * olsr_get_next_list_entry
  18 + *
  19 + * Get the next list node in a hash bucket.
  20 + * The listnode of the timer in may be subject to getting removed from
  21 + * this timer bucket in olsr_change_timer() and olsr_stop_timer(), which
  22 + * means that we can miss our walking context.
  23 + * By caching the previous node we can figure out if the current node
  24 + * has been removed from the hash bucket and compute the next node.
  25 + */
  26 +static struct list_node *
  27 +olsr_get_next_list_entry (struct list_node **prev_node,
  28 +                          struct list_node *current_node)
  29 +{
  30 +  if ((*prev_node)->next == current_node) {
  31 +
  32 +    /*
  33 +     * No change in the list, normal traversal, update the previous node.
  34 +     */
  35 +    *prev_node = current_node;
  36 +    return (current_node->next);
  37 +  } else {
  38 +
  39 +    /*
  40 +     * List change. Recompute the walking context.
  41 +     */
  42 +    return ((*prev_node)->next);
  43 +  }
  44 +}
  45
  46  /**
  47   * Walk through the timer list and check if any timer is ready to fire.
  48 @@ -326,7 +354,7 @@ olsr_walk_timers(clock_t * last_run)
  49  olsr_walk_timers(clock_t * last_run)
  50  {
  51    static struct timer_entry *timer;
  52 -  struct list_node *timer_head_node;
  53 +  struct list_node *timer_head_node, *timer_walk_node, *timer_walk_prev_node;
  54    unsigned int timers_walked, timers_fired;
  55    unsigned int total_timers_walked, total_timers_fired;
  56    unsigned int wheel_slot_walks = 0;
  57 @@ -347,12 +375,15 @@ olsr_walk_timers(clock_t * last_run)
  58
  59      /* Get the hash slot for this clocktick */
  60      timer_head_node = &timer_wheel[*last_run & TIMER_WHEEL_MASK];
  61 +    timer_walk_prev_node = timer_head_node;
  62
  63      /* Walk all entries hanging off this hash bucket */
  64 -    for (timer_walk_list_node = timer_head_node->next; timer_walk_list_node != timer_head_node;        /* circular list */
  65 -        timer_walk_list_node = timer_walk_list_node->next) {
  66 -
  67 -      timer = list2timer(timer_walk_list_node);
  68 +    for (timer_walk_node = timer_head_node->next;
  69 +         timer_walk_node != timer_head_node; /* circular list */
  70 +        timer_walk_node = olsr_get_next_list_entry(&timer_walk_prev_node,
  71 +                                                    timer_walk_node)) {
  72 +
  73 +      timer = list2timer(timer_walk_node);
  74
  75        timers_walked++;
  76
  77 @@ -403,11 +434,6 @@ olsr_walk_timers(clock_t * last_run)
  78      /* Increment the time slot and wheel slot walk iteration */
  79      (*last_run)++;
  80      wheel_slot_walks++;
  81 -
  82 -    /*
  83 -     * Mark the timer walk context unused.
  84 -     */
  85 -    timer_walk_list_node = NULL;
  86    }
  87
  88  #ifdef DEBUG
  89 @@ -581,21 +607,6 @@ olsr_start_timer(unsigned int rel_time,
  90    return timer;
  91  }
  92
  93 -/*
  94 - * Check if there is a timer walk in progress and advance the
  95 - * walking context if so. Keep in mind we are about to delete
  96 - * the timer from a list and this will destroy the walking context.
  97 - */
  98 -
  99 -static inline void
 100 -olsr_update_timer_walk_ctx(struct timer_entry *timer)
 101 -{
 102 -  if (timer_walk_list_node == &timer->timer_list) {
 103 -    timer_walk_list_node = timer_walk_list_node->next;
 104 -  }
 105 -}
 106 -
 107 -
 108  /**
 109   * Delete a timer.
 110   *
 111 @@ -615,8 +626,6 @@ olsr_stop_timer(struct timer_entry *time
 112               olsr_cookie_name(timer->timer_cookie),
 113               timer, timer->timer_cb_context);
 114  #endif
 115 -
 116 -  olsr_update_timer_walk_ctx(timer);
 117
 118    /*
 119     * Carve out of the existing wheel_slot and return to the pool
 120 @@ -658,8 +667,6 @@ olsr_change_timer(struct timer_entry *ti
 121    timer->timer_clock = olsr_jitter(rel_time, jitter_pct, timer->timer_random);
 122    timer->timer_jitter_pct = jitter_pct;
 123
 124 -  olsr_update_timer_walk_ctx(timer);
 125 -
 126    /*
 127     * Changes are easy: Remove timer from the exisiting timer_wheel slot
 128     * and reinsert into the new slot.
 129
 130
 131
 132