__radix_tree_lookup(9)

📦 version 7.3.1, in nixpkgs unstable

💅 __radix_tree_lookup(9) — the Kernel API Manual glow-up 💅

okay bestie, welcome to the Kernel API Manual page for __radix_tree_lookup(9) — she's giving lookup-core, she's giving radix-tree realness, and we're gonna get through it together 🫶✨

🌸 NAME 🌸

__radix_tree_lookup — lookup an item in a radix tree 💖

✨ SYNOPSIS ✨

void * __radix_tree_lookup (const struct radix_tree_root *root ,
unsigned long index , struct radix_tree_node **nodep , void __rcu
***slotp );

🎀 ARGUMENTS 🎀

  • root — radix tree root 👑
  • index — index key 🔑
  • nodep — returns node 📦
  • slotp — returns slot 🕳️

🦋 DESCRIPTION 🦋

Lookup and return the item at position index in the radix tree root. Slay, that's the whole vibe ✨

But wait, there's a lil detail, and it's lowkey important: until there is more than one item in the tree, no nodes are allocated, and root->xa_head is used as a direct slot instead of pointing to a node — in which case *nodep will be NULL 😭💀

🌈 SEE ALSO 🌈

Kernel file ./lib/radix-tree.c — and honestly the whole radix-tree friend group showed up:

mwah 💖 this page came from ./lib, dated October 2026, and it's literally called __radix_tree_lookup(9) — periodt 🎀✨

📦 where this page comes from