Re: [PATCH v3 1/9] mm: Introduce new vm_insert_range API

[Matthew Wilcox]

On Fri, Dec 07, 2018 at 03:34:56PM +0000, Robin Murphy wrote:
> > +int vm_insert_range(struct vm_area_struct *vma, unsigned long addr,
> > +                   struct page **pages, unsigned long page_count)
> > +{
> > +   unsigned long uaddr = addr;
> > +   int ret = 0, i;
> 
> Some of the sites being replaced were effectively ensuring that vma and
> pages were mutually compatible as an initial condition - would it be worth
> adding something here for robustness, e.g.:
> 
> +     if (page_count != vma_pages(vma))
> +             return -ENXIO;

I think we want to allow this to be used to populate part of a VMA.
So perhaps:

        if (page_count > vma_pages(vma))
                return -ENXIO;