try 5.4.284

support/ebpf/hash.h

@@ -6,47 +6,58 @@
 #define ROUNDUP_8(x) ((x + 7) & ~7)
 static inline __attribute__((__always_inline__))
 bool hash_custom_labels(CustomLabelsArray *lbls, int seed, u64 *out) {
-    // apply murmurhash2 as though this is an array of
-    // the number of labels (8 bytes), followed by all the key/val lengths,
-    // followed by all the keys/vals.
-    const u64 m = 0xc6a4a7935bd1e995LLU;
-    const int r = 47;
+  // apply murmurhash2 as though this is an array of
+  // the number of labels (8 bytes), followed by all the key/val lengths,
+  // followed by all the keys/vals.
+  const u64 m = 0xc6a4a7935bd1e995LLU;
+  const int r = 47;
+  unsigned num_lbls = lbls->len;
 
-    int len = 8;
-    for (int i = 0; i < MAX_CUSTOM_LABELS; ++i) {
-        if (i >= lbls->len)
-            break;
-        len += 8;
-        len += ROUNDUP_8(lbls->labels[i].key_len);
-        len += ROUNDUP_8(lbls->labels[i].val_len);
-    }
+  if (num_lbls > MAX_CUSTOM_LABELS) {
+    num_lbls = MAX_CUSTOM_LABELS;
+  }
 
-    u64 h = seed ^ (len * m);
+  int len = 8;
+  for (u32 i = 0; i < MIN(num_lbls, MAX_CUSTOM_LABELS); ++i) {
+    // Extra check to appease 5.4 kernels.
+    if (i >= MAX_CUSTOM_LABELS)
+      break;
+    len += 8;
+    len += ROUNDUP_8(lbls->labels[i].key_len);
+    len += ROUNDUP_8(lbls->labels[i].val_len);
+  }
 
-    // hash the number of labels
-    {
-        u64 k = lbls->len;
-        k *= m;
-        k ^= k >> r;
-        k *= m;
+  u64 h = seed ^ (len * m);
 
-        h ^= k;
-        h *= m;
-    }
+  // hash the number of labels
+  {
+      u64 k = lbls->len;
+      k *= m;
+      k ^= k >> r;
+      k *= m;
+
+      h ^= k;
+      h *= m;
+  }
 
   // hash each k/v len
-  for (int i = 0, n = MIN(MAX_CUSTOM_LABELS,lbls->len); i < n; i++) {
+  for (u32 i = 0, n = MIN(MAX_CUSTOM_LABELS,num_lbls); i < n; i++) {
+    // Extra check to appease 5.4 kernels.
+    if (i >= MAX_CUSTOM_LABELS)
+      break;
     u64 k = (((u64)lbls->labels[i].key_len) << 32) | ((u64)lbls->labels[i].val_len);
     k *= m;
     k ^= k >> r;
     k *= m;
 
-        h ^= k;
-        h *= m;
-    }
+    h ^= k;
+    h *= m;
+  }
 
   // hash each k/v
-  for (int i = 0, n = MIN(MAX_CUSTOM_LABELS,lbls->len); i < n; i++) {
+  for (u32 i = 0, n = MIN(MAX_CUSTOM_LABELS,num_lbls); i < n; i++) {
+    if (i >= MAX_CUSTOM_LABELS)
+      break;
     CustomLabel *lbl = &lbls->labels[i];
     u64 kl           = ROUNDUP_8(lbl->key_len);
 #pragma unroll
@@ -71,17 +82,17 @@ bool hash_custom_labels(CustomLabelsArray *lbls, int seed, u64 *out) {
       k ^= k >> r;
       k *= m;
 
-            h ^= k;
-            h *= m;
-        }
+      h ^= k;
+      h *= m;
     }
 
     h ^= h >> r;
     h *= m;
     h ^= h >> r;
+  }
 
-    *out = h;
-    return true;
+  *out = h;
+  return true;
 }
 
 #endif