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

[Alice Ryhl]

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)
    }
};

Alice