rht_for_each_entry_rcu_from(9)

✨ NAME ✨

hey bestie, welcome to rht_for_each_entry_rcu_from(9) in the Kernel API Manual — yes, the title is a whole mouthful, and the vibe is iterating over an rcu hash chain from a given head. The official one-liner is rht_for_each_entry_rcu_from — iterated over rcu hash chain from given head. 🦋

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🌸 SYNOPSIS 🌸

exact call shape, character for character, no edits, periodt:

rht_for_each_entry_rcu_from (tpos , pos , head , tbl , hash , member );

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💅 ARGUMENTS 💅

okay so here’s the cast, bestie — every single one matters:

• tpos — the type * to use as a loop cursor. 🎀
• pos — the struct rhash_head to use as a loop cursor.
• head — the struct rhash_head to start from.
• tbl — the struct bucket_table.
• hash — the hash value / bucket index.
• member — name of the struct rhash_head within the hashable struct.

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🔥 DESCRIPTION 🔥

okay so this is a hash chain list-traversal primitive, and the main character energy is that it may safely run concurrently with the _rcu mutation primitives such as rhashtable_insert — as long as the traversal is guarded by rcu_read_lock. That’s the whole safety vibe. No cap.

fr fr, do not skip the rcu_read_lock guard: the safety promise is literally tied to it. 💀

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🌈 SEE ALSO 🌈

Kernel file ./include/linux/rhashtable.h, plus the whole friend group: struct bucket_table(9), rht_grow_above_75(9), rht_shrink_below_30(9), rht_grow_above_100(9), rht_grow_above_max(9), rht_for_each_from(9), rht_for_each(9), rht_for_each_entry_from(9), rht_for_each_entry(9), rht_for_each_entry_safe(9), rht_for_each_rcu_from(9), rht_for_each_rcu(9), rht_for_each_entry_rcu(9), rhl_for_each_rcu(9), rhl_for_each_entry_rcu(9), rhashtable_lookup(9), rhashtable_lookup_fast(9), rhltable_lookup(9), rhashtable_insert_fast(9), rhltable_insert_key(9), rhltable_insert(9), rhashtable_lookup_insert_fast(9), rhashtable_lookup_get_insert_fast(9), rhashtable_lookup_insert_key(9), rhashtable_lookup_get_insert_key(9), rhashtable_remove_fast(9), rhltable_remove(9), rhashtable_replace_fast(9), rhltable_walk_enter(9), rhltable_free_and_destroy(9). 🫶

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mwah 💋 — source/version says ./include/linux, date says October 2026, and the page is rht_for_each_entry_rcu_from(9). stay slay, bestie 🫶✨