hlist_bl_add_head_rcu(9)

💖 hlist_bl_add_head_rcu(9) 💖

okay so this is the Kernel API Manual page for hlist_bl_add_head_rcu(9), and it's giving very specific kernel-list energy. 🫶 We're gonna keep every tiny detail, bestie — no cap.

✨ NAME ✨

The original NAME section is, and I quote, just:

hlist_bl_add_head_rcu -

No extra description after the dash, and I'm not inventing one — the function name is the whole moment. 💅

🦋 SYNOPSIS 🦋

       void hlist_bl_add_head_rcu (struct hlist_bl_node *n , struct
       hlist_bl_head *h );

That's the whole signature, including the little space before the comma after *n — copy it exactly if you're typing it out, okay? ✨

🎀 ARGUMENTS 🎀

• n — the element to add to the hash list. 🍓
• h — the list to add to. 🌸

💅 DESCRIPTION 💅

Adds the specified element to the specified hlist_bl, 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_bl_add_head_rcu or hlist_bl_del_rcu, running on this same list. That's the caution-tape part, bestie — don't skip it. 😭

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

Regardless of the type of CPU, the list-traversal primitive must be guarded by rcu_read_lock. Periodt. 💅

🌈 SEE ALSO 🌈

• Kernel file ./include/linux/rculist_bl.h
• hlist_bl_del_rcu(9)
• hlist_bl_for_each_entry_rcu(9)
• hlist_bl_for_each_entry_continue_rcu(9)

That's the whole crossover episode, and it ate. 🔥

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okay bye bestie 💖 — this page's footer says source/version ./include/linux and date October 2026, with hlist_bl_add_head_rcu(9) on it too. 🎀✨