Re: [PATCH bpf-next v5 2/4] xsk: Support UMEM chunk_size > PAGE_SIZE

[Kal Cutter Conley]

> > -       pool->unaligned = unaligned;
> >         pool->frame_len = umem->chunk_size - umem->headroom -
> >                 XDP_PACKET_HEADROOM;
> > +       pool->unaligned = unaligned;
>
> nit: This change is not necessary.

Do you mind if we keep it? It makes the assignments better match the
order in the struct declaration.

> > -static void xp_check_dma_contiguity(struct xsk_dma_map *dma_map)
> > +static void xp_check_dma_contiguity(struct xsk_dma_map *dma_map, u32 page_size)
> >  {
> >         u32 i;
> >
> > -       for (i = 0; i < dma_map->dma_pages_cnt - 1; i++) {
> > -               if (dma_map->dma_pages[i] + PAGE_SIZE == dma_map->dma_pages[i + 1])
> > +       for (i = 0; i + 1 < dma_map->dma_pages_cnt; i++) {
>
> I think the previous version is clearer than this new one.

I like using `i + 1` since it matches the subscript usage. I'm used to
writing it like this for SIMD code where subtraction may wrap if the
length is unsigned, that doesn't matter in this case though. I can
restore the old way if you want.