On 03/15/2018 10:21 AM, Ram Pai wrote: > On Thu, Mar 15, 2018 at 08:55:31AM -0700, Dave Hansen wrote: >> On 03/15/2018 02:46 AM, Thomas Gleixner wrote: >>>> + if (!pkey || !mm_pkey_is_allocated(mm, pkey)) >>> Why this extra check? mm_pkey_is_allocated(mm, 0) should not return true >>> ever. If it does, then this wants to be fixed. >> I was thinking that we _do_ actually want it to seem allocated. It just >> get "allocated" implicitly when an mm is created. I think that will >> simplify the code if we avoid treating it specially in as many places as >> possible. > I think, the logic that makes pkey-0 special must to go > in arch-neutral code. How about checking for pkey-0 in sys_pkey_free() > itself? This is for protection against shooting yourself in the foot? Yes, that can go in sys_pkey_free(). Does this need manpage and/or selftests updates?