>> It's listed in Documentation/atomic_bitops.txt. > > Oh, so my memory was actually correct that I saw it in the docs > somewhere. > WDYT, should I mention this here in the code (block comment) as well > that it's atomic and must not lose `volatile` as Andy suggested or > it's sufficient to have it in the docs (+ it's not underscored)? I think a comment that the "volatile" is required to prevent re-ordering is enough. But maybe others are sufficiently clear on the meaning? I once wasted time looking for the non-atomic __test_bit() version (to use in some code that was already protected by a spin lock, so didn't need the overhead of an "atomic" version) before realizing there wasn't a non-atomic one. -Tony