rht_for_each_entry_rcu(9)

💖 rht_for_each_entry_rcu — the Kernel API Manual, but make it group chat 💖

okay so bestie, you're in the Kernel API Manual and today's main character is a macro. yes a macro. don't scroll away, this one lowkey slaps ✨

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🦋 NAME 🦋

rht_for_each_entry_rcu — iterate over rcu hash chain of given type

like, that's the whole job. that's the assignment. she iterates and she does it over an rcu hash chain, and the chain is of a given type. periodt 💅

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🌸 SYNOPSIS 🌸

rht_for_each_entry_rcu (tpos , pos , tbl , hash , member );

that's the spell. recite it exactly, iykyk 🎀

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✨ ARGUMENTS ✨

• tpos — the type * to use as a loop cursor. think of her as the glow-up variable that holds whatever you're actually looking at 💖
• pos — the struct rhash_head to use as a loop cursor. this one's the little chain-link that keeps track of where you're standing in the list 🫶
• tbl — the struct bucket_table. the whole vibe container. every bucket lives here 🪣
• hash — the hash value / bucket index. which bucket are we sliding into? that's her 🌈
• member — name of the struct rhash_head within the hashable struct. yes you have to tell her the field name, she's not a mind reader 😭

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👑 DESCRIPTION 👑

so here's the tea, bestie 🍓

This hash chain list-traversal primitive may safely run concurrently with the _rcu mutation primitives such as rhashtable_insert — as long as the traversal is guarded by rcu_read_lock.

read that again. as long as. the guard is not optional, it's the whole plot 🔥 the concurrency works because you locked first, not because you got lucky. no lock = no slay, fr fr 💀

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🧚 SEE ALSO 🧚

Kernel file ./include/linux/rhashtable.h and honestly her 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_from(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)

thirty-one entries. i counted. she's popular, what can i say 💅

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aaaaand that's the page 🎀 this beauty lives at ./include/linux, dated October 2026, and she's filed under the Kernel API Manual — go forth, guard your traversal with rcu_read_lock, and iterate like the icon you are 💜🦋✨