Re: [PATCH 03/16] mm: add vma_desc_size(), vma_desc_pages() helpers

Jason Gunthorpe
2025-09-08T12:51:10Z

On Mon, Sep 08, 2025 at 12:10:34PM +0100, Lorenzo Stoakes wrote:
> static int secretmem_mmap_prepare(struct vm_area_desc *desc)
> {
> - const unsigned long len = desc->end - desc->start;
> + const unsigned long len = vma_desc_size(desc);
>
> if ((desc->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
> return -EINVAL;

I wonder if we should have some helper for this shared check too, it
is a bit tricky with the two flags. Forced-shared checks are pretty
common.

vma_desc_must_be_shared(desc) ?

Also 'must not be exec' is common too.

Jason