Documentation of locking needs when working with lists?

[Heiner Kallweit <hkallweit1@gmail.com>]

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!