hash_for_each_rcu(9)

📦 version 7.3.1, in nixpkgs unstable

💅 hash_for_each_rcu — like, the Kernel API Manual page, bestie 🎀

Okay so picture this: you're deep in ./include/linux/hashtable.h, the vibes are immaculate, and you need to walk a whole RCU-enabled hashtable, entry by entry. That's literally this macro. It's giving "loop over everything, safely, while the rest of the kernel is out there living its best life." ✨

🌸 NAME 🌸

hash_for_each_rcu — iterate over a rcu enabled hashtable

Yes bestie, that's the whole job. Iterate. Over a hashtable. One that has RCU enabled. No cap. 🦋

✨ SYNOPSIS ✨

hash_for_each_rcu (name , bkt , obj , member );

Look at her. Four args, one line, absolutely iconic. 👑

💖 ARGUMENTS 💖

  • name — the hashtable you're iterating, the main character of this whole operation. 🫶
  • bkt — an integer you get to use as the bucket loop cursor. She's the little index that keeps track of where you are, lowkey doing so much work behind the scenes. 🔥
  • obj — the type * to use as a loop cursor for each entry — like, the pointer type that gets handed to you on every pass through the loop. ⭐
  • member — the name of the hlist_node within the struct. Like, which field inside your struct is the one that actually links it into the hashtable. That's her. That's the connector. 🧚

👀 SEE ALSO 👀

Kernel file ./include/linux/hashtable.h — and honestly the whole friend group lives in there:

All of them are in the group chat, all of them slay in their own special way, and you should absolutely go say hi. 💜

Ngl, this macro only ever got written down in June 2026 — like, freshly documented, we love a queen who just arrived. 🙈

And that's a wrap, bestie — page brought to you by ./include/linux, dated October 2026, in the one and only Kernel API Manual. Go forth and iterate. Mwah. 💅💖🎀🌸🦋

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