On Mon, Sep 21, 2020 at 11:43:38PM +0200, Jann Horn wrote: > On Mon, Sep 21, 2020 at 11:17 PM Peter Xu <peterx@xxxxxxxxxx> wrote: > > > > (Commit message collected from Jason Gunthorpe) > > > > Reduce the chance of false positive from page_maybe_dma_pinned() by keeping > > track if the mm_struct has ever been used with pin_user_pages(). mm_structs > > that have never been passed to pin_user_pages() cannot have a positive > > page_maybe_dma_pinned() by definition. > > There are some caveats here, right? E.g. this isn't necessarily true > for pagecache pages, I think? Sorry I didn't follow here. Could you help explain with some details? Thanks, -- Peter Xu
