hlist_nulls_del_rcu(9)

📦 version 7.3.1, in nixpkgs unstable

💅 hlist_nulls_del_rcu 💅

okay so bestie, welcome to the Kernel API Manual page for hlist_nulls_del_rcu — she's a kernel function, she's from ./include/linux, and she is literally the moment 💖

✨ NAME ✨

hlist_nulls_del_rcu — deletes an entry from a hash list without re-initialization. no re-init, no problem, she just leaves 🦋

🎀 SYNOPSIS 🎀

void hlist_nulls_del_rcu (struct hlist_nulls_node *n );

🌸 ARGUMENTS 🌸

  • n — the element to delete from the hash list. that's her, that's the girl you're removing 👑

💀 NOTE 💀

okay this is the part where you actually have to pay attention, bestie, because it's giving important caveats 😭

hlist_nulls_unhashed on entry does not return true after this. nope. the entry is in an undefined state. that's not a vibe, that's just facts. she's undefined now, periodt.

it is useful for RCU based lockfree traversal tho — that's literally her whole purpose ✨

in particular 👇 it means that we can not poison the forward pointers that may still be used for walking the hash list. so don't go trying to poison them, she said no 🙈

⚠️ the caller must take whatever precautions are necessary (such as holding appropriate locks) to avoid racing with another list-mutation primitive — think hlist_nulls_add_head_rcu or hlist_nulls_del_rcu — running on this same list. so like, protect yourself. lock it up. 🔒

but 💅 however — it is perfectly legal to run concurrently with the _rcu list-traversal primitives, such as hlist_nulls_for_each_entry. so reading while deleting? totally fine, iconic, no notes.

👀 SEE ALSO 👀

kernel file ./include/linux/rculist_nulls.h, plus the whole friend group 🫶:

and that's the whole page, bestie!! 🎀✨ this one lives in ./include/linux, dated October 2026, and she goes by hlist_nulls_del_rcu(9) — lowkey a whole icon, no cap 💜🦋 slay

📦 where this page comes from