Re: [PATCH v2 3/5] rust: scatterlist: Add type-state abstraction for sg_table

[Danilo Krummrich]

On 8/22/25 1:52 PM, Alice Ryhl wrote:
> On Fri, Aug 22, 2025 at 01:48:47PM +0200, Danilo Krummrich wrote:
> > On Fri Aug 22, 2025 at 1:44 PM CEST, Alice Ryhl wrote:
> > > > +impl<P> Owned<P>
> > > > +where
> > > > +    for<'a> P: page::AsPageIter<Iter<'a> = VmallocPageIter<'a>> + 'static,
> > > > +{
> > > > +    fn new(
> > > > +        dev: &Device<Bound>,
> > > > +        mut pages: P,
> > > > +        dir: dma::DataDirection,
> > > > +        flags: alloc::Flags,
> > > > +    ) -> Result<impl PinInit<Self, Error> + '_> {
> > > > +        let page_iter = pages.page_iter();
> > > > +        let size = page_iter.size();
> > >
> > > Variable naming here is confusing. There's another variable called size
> > > in an inner scope, and then afterwards in RawSGTable you use *this* size
> > > variable again.
> >
> > I can change the size in the assignment block of max_segment to max_size, or do
> > you have other suggestions?
>
> How about just this?
>
> let max_segment = {
>      // SAFETY: `dev.as_raw()` is a valid pointer to a `struct device`.
>      let max_segment = unsafe { bindings::dma_max_mapping_size(dev.as_raw()) };
>      if max_segment == 0 {
>          u32::MAX
>      } else {
>          u32::try_from(max_segment).unwrap_or(u32::MAX)
>      }
> };

Looks good, thanks!