hlist_add_before_rcu(9)

📦 version 7.3.1, in nixpkgs unstable

okay so this is the hlist_add_before_rcu(9) page from the Kernel API Manual, and it’s literally the “put this new hlist node before that existing node while RCU traversals keep vibing” moment. 💅✨

💖 NAME 💖

hlist_add_before_rcu(9) — and after the dash? literally nothing in the original, bestie. iconic mystery behavior. 🫶

✨ SYNOPSIS ✨

void hlist_add_before_rcu (struct hlist_node *n , struct hlist_node
       *next );

🎀 ARGUMENTS 🎀

  • n — the new element to add to the hash list. 🍓
  • next — the existing element to add the new element before. 🎀

🦋 DESCRIPTION 🦋

okay so here’s the tea: this adds the specified element to the specified hlist before the specified node while permitting racing traversals. ✨

The caller must take whatever precautions are necessary (such as holding appropriate locks) to avoid racing with another list-mutation primitive, such as hlist_add_head_rcu or hlist_del_rcu, running on this same list. that part is on you, bestie — no cap. 😭

However, it is perfectly legal to run concurrently with the _rcu list-traversal primitives, such as hlist_for_each_entry_rcu, used to prevent memory-consistency problems on Alpha CPUs. iconic. 💅🔥

🌈 SEE ALSO 🌈

Kernel file: ./include/linux/rculist.h — and the whole SEE ALSO crew is: 👑

that’s the hlist_add_before_rcu(9) manual page, sourced from ./include/linux, dated October 2026 — periodt, mwah 💋🫶

📦 where this page comes from