linux-kernel - Documentation of locking needs when working with lists?

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Message-ID: <4f405d9b-460c-49f7-91b2-d147d9818369@gmail.com>
Date: Sat, 10 May 2025 10:46:32 +0200
From: Heiner Kallweit <hkallweit1@...il.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
 Ingo Molnar <mingo@...nel.org>
Cc: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Documentation of locking needs when working with lists?

Even though lists are used everywhere, I was surprised not being able to find
documentation about which operations need locking, and which ones are safe
lock-less.

My case:
I have a list where the only operation is adding entries.
It's clear that adding entries has to be serialized.
Question is whether a list_for_each_entry is safe lock-less.

Looking at the code I *think* it's safe, under the precondition that
reading/writing pointers is atomic.

Any hint or documentation link would be appreciated. Thanks!