Messages in this thread |  | | From | Linus Torvalds <> | Date | Mon, 26 Jul 2021 10:15:31 -0700 | Subject | Re: [PATCH v3 1/7] iov_iter: Introduce fault_in_iov_iter helper |
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On Mon, Jul 26, 2021 at 9:33 AM Jan Kara <jack@suse.cz> wrote: > > On Fri 23-07-21 22:58:34, Andreas Gruenbacher wrote: > > + gup_flags = FOLL_TOUCH | FOLL_POPULATE; > > I don't think FOLL_POPULATE makes sense here. It makes sense only with > FOLL_MLOCK and determines whether mlock(2) should fault in missing pages or > not.
Yeah, it won't hurt, but FOLL_POPULATE doesn't actually do anything unless FOLL_MLOCK is set. It is, as you say, a magic flag just for mlock.
The only ones that should matter are FOLL_WRITE (for obvious reasons) and FOLL_TOUCH (to set the accessed and dirty bits, rather than just th protection bits)
Linus
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