seq_hlist_next_rcu(9)

📦 version 7.3.1, in nixpkgs unstable

✨ seq_hlist_next_rcu ✨

okay bestie, welcome to the Kernel API Manual — this is the page for seq_hlist_next_rcu(9), and it's literally about moving to the next spot in an hlist that's protected by RCU 🦋

🌸 NAME 🌸

seq_hlist_next_rcu — move to the next position of the hlist protected by RCU 💅

✨ SYNOPSIS ✨

struct hlist_node * seq_hlist_next_rcu (void *v , struct hlist_head *head , loff_t *ppos );

like, that's the whole signature, no cap 👑

🎀 ARGUMENTS 🎀

  • v — the current iterator 🌀 like, where you're at right now
  • head — the head of the hlist 🌈 the starting point of the whole thing
  • ppos — the current position 📍 the position tracker, bestie

💖 DESCRIPTION 💖

So this one gets called at seq_file->op->next. That's the vibe — it's the "next" callback of your seq_file ops, doing its little traversal thing ✨

Here's the important part, and I need you to hear me on this: this list-traversal primitive may safely run concurrently with the _rcu list-mutation primitives — like hlist_add_head_rcu — as long as the traversal is guarded by rcu_read_lock. 🔒

fr fr, that rcu_read_lock guard is not optional. concurrent-safe only counts with the guard, so don't be out here skipping it 😭

🫶 SEE ALSO 🫶

Kernel file ./fs/seq_file.c plus this whole little friend group of seq helpers:

aaaand that's the page, bestie 💜 this one lives in ./fs, dated October 2026 — mwah, go read the whole family of seq_hlist_* friends, they all slay 🌟

📦 where this page comes from