Handle leaves above the bottom in radix_iterator2

descend will still break. Also we don't create them yet. But descend probably needs to change.

Handle leaves above the bottom in radix_iterator2
5a92c5ee · David Benjamin · bd57e37a · 5a92c5ee · 5a92c5ee
--- a/include/radix.hh
+++ b/include/radix.hh
@@ -222,6 +222,7 @@ struct radix_iterator2 {
  // leaves are at level 0. Later we'll steal a bit for them. The root
  // is path_[radix_levels].
  radix_entry path_[radix_levels+1];
+  u32 leaf_;
  radix_iterator2(const radix* r, u64 k);
@@ -230,7 +231,7 @@ struct radix_iterator2 {
    return *this;
  }
  radix_elem* operator*() {
-    return path_[0].elem();
+    return path_[leaf_].elem();
  }
  radix_node* node(u32 level) { return path_[level].node(); }

--- a/kernel/radix.cc
+++ b/kernel/radix.cc
@@ -188,7 +188,9 @@ radix_iterator2::radix_iterator2(const radix* r, u64 k)
  dprintf("%p: Made iterator with k = %lu\n", r_, k_);
  if (k_ != ~0ULL) {
    path_[radix_levels] = r_->root_.load();
-    if (!find_first_leaf(radix_levels - 1))
+    if (path_[radix_levels].is_elem())
+      leaf_ = radix_levels; // Maybe best to not do this...
+    else if (!find_first_leaf(radix_levels - 1))
      k_ = ~0ULL;
  }
  dprintf("%p: Adjusted: k = %lu\n", r_, k_);
@@ -198,7 +200,7 @@ bool
 radix_iterator2::advance(u32 level)
 {
  // First, see if we can advance a lower level.
-  if (level > 0 && advance(level-1)) {
+  if (level > leaf_ && advance(level-1)) {
    // Nothing more to do.
    return true;
  }
@@ -230,7 +232,12 @@ radix_iterator2::find_first_leaf(u32 level)
      }
      path_[level] = next;
-      if (level == 0 || find_first_leaf(level-1))
+      if (next.is_elem()) {
+        // Found a leaf. Stop now.
+        leaf_ = level;
+        return true;
+      } else if (find_first_leaf(level-1))
+        // Keep looking.
        return true;
    }
  }