radix_tree_lookup_slot(9)

📦 version 7.3.1, in nixpkgs unstable

✨ radix_tree_lookup_slot ✨

okay so bestie, this is the radix_tree_lookup_slot page from the Kernel API Manual and it's literally all about grabbing a slot out of a radix tree 🌳💅 no cap, it's a whole thing and we're gonna get through it together 🫶

🌸 SYNOPSIS 🌸

void __rcu ** radix_tree_lookup_slot (const struct radix_tree_root *root
, unsigned long index );

like, that's the whole signature, slay ✨

🎀 ARGUMENTS 🎀

  • root — the radix tree root, aka where it all begins, the main character of the tree 👑
  • index — the index key, the lil coordinate you're looking up 🔑

💖 RETURN 💖

so it returns the slot corresponding to the position index in the radix tree root. it's giving "find my spot" energy 🎯

and lowkey, this one is useful for update-if-exists operations — like, if you wanna update something only when it's already there, this is your girl 💁‍♀️

🦋 DESCRIPTION 🦋

okay this is the important part, bestie, listen up 👂

This function can be called under rcu_read_lock iff the slot is not modified by radix_tree_replace_slot, otherwise it must be called exclusive from other writers. periodt.

⚠️ and ALSO — any dereference of the slot must be done using radix_tree_deref_slot. do not skip this, it's not a vibe to ignore it fr fr 💀

🌈 SEE ALSO 🌈

so here's the whole friend group, the entire squad of related calls, iconic lineup honestly 🧚✨:

and that's the whole page, bestie, you ate that 💅✨ big thank you to ./lib for this one, dated October 2026 — we stan a documented kernel 🫶🎀

📦 where this page comes from