rrl: fix zero increment in KRU

CZ-NIC · Oct 3, 2024 · 623bb9a · 623bb9a
1 parent 75d6162
commit 623bb9a
Showing 1 changed file with 4 additions and 3 deletions.
diff --git a/src/knot/modules/rrl/kru.inc.c b/src/knot/modules/rrl/kru.inc.c
@@ -230,7 +230,8 @@ struct query_ctx {
  struct load_cl *l[TABLE_COUNT];
  uint32_t time_now;
  kru_price_t price;
- uint16_t price16, limit16;
+ uint16_t price16;
+ uint32_t limit16; // 2^16 has to be representable
  uint16_t id;
  uint16_t final_load_value; // set by kru_limited_update if not blocked
  uint16_t *load;
@@ -360,7 +361,7 @@ static inline bool kru_limited_fetch(struct kru *kru, struct query_ctx *ctx)
  const kru_price_t fract = price & ((((kru_price_t)1) << fract_bits) - 1);
 
  ctx->price16 = price >> fract_bits;
- ctx->limit16 = -ctx->price16;
+ ctx->limit16 = (1<<16) - ctx->price16;
 
  if ((fract_bits > 0) && (fract > 0)) {
  ctx->price16 += (rand_bits(fract_bits) < fract);
@@ -474,7 +475,7 @@ static inline bool kru_limited_update(struct kru *kru, struct query_ctx *ctx, bo
 
  static_assert(ATOMIC_CHAR16_T_LOCK_FREE == 2, "insufficient atomics");
  const uint16_t price = ctx->price16;
- const uint16_t limit = ctx->limit16;
+ const uint32_t limit = ctx->limit16; // 2^16 has to be representable
  uint16_t load_orig = atomic_load_explicit(load_at, memory_order_relaxed);
  uint16_t load_new;
  do {