On Wed 19-10-16 09:59:03, Jan Kara wrote: > On Thu 13-10-16 01:20:18, Lorenzo Stoakes wrote: > > This patch removes the write parameter from __access_remote_vm() and replaces it > > with a gup_flags parameter as use of this function previously _implied_ > > FOLL_FORCE, whereas after this patch callers explicitly pass this flag. > > > > We make this explicit as use of FOLL_FORCE can result in surprising behaviour > > (and hence bugs) within the mm subsystem. > > > > Signed-off-by: Lorenzo Stoakes <lstoakes@xxxxxxxxx> > > So I'm not convinced this (and the following two patches) is actually > helping much. By grepping for FOLL_FORCE we will easily see that any caller > of access_remote_vm() gets that semantics and can thus continue search I am really wondering. Is there anything inherent that would require FOLL_FORCE for access_remote_vm? I mean FOLL_FORCE is a really non-trivial thing. It doesn't obey vma permissions so we should really minimize its usage. Do all of those users really need FOLL_FORCE? Anyway I would rather see the flag explicit and used at more places than hidden behind a helper function. -- Michal Hocko SUSE Labs
