Re: [PATCH v5 02/16] iov_iter: add iterator type for dmabuf maps

[Pavel Begunkov]

On 8/3/26 14:20, Anuj gupta wrote:
> On Sat, Aug 1, 2026 at 9:19 PM Pavel Begunkov <asml.silence@xxxxxxxxx> wrote:
> > @@ -841,7 +857,7 @@ static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i)
> >
> >   unsigned long iov_iter_alignment(const struct iov_iter *i)
> >   {
> > -       if (likely(iter_is_ubuf(i))) {
> > +       if (likely(iter_is_ubuf(i)) || iov_iter_is_dmabuf_map(i)) {
> >                  size_t size = i->count;
> >                  if (size)
> >                          return ((unsigned long)i->ubuf + i->iov_offset) | size;
>
> dmabuf_map shares the same union slot as ubuf, so this reads the map
> pointer as a user address. gap_alignment() below already returns 0
> correctly for dmabuf - this should too. Checked the rest of this patch
> (advance/revert/restore) - none of them dereference the union pointer
> for dmabuf, so it's isolated to this one spot. Doesn't affect the
> current series, nothing reaches this with a dmabuf iter yet.

Ah yes, that's nonsense, it should've checked iov_offset instead. Thanks

--
Pavel Begunkov