Re: [PATCH 20/22] mm/mremap: Use vma_lookup() in vma_to_resize()

[Davidlohr Bueso <dave@xxxxxxxxxxxx>]

On Mon, 10 May 2021, Liam Howlett wrote:

> Use vma_lookup() to find the VMA at a specific address.  As vma_lookup()
> will return NULL if the address is not within any VMA, the start address
> no longer needs to be validated.
>
> Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
> ---
> mm/mremap.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/mremap.c b/mm/mremap.c
> index 47c255b60150..04143755cd1e 100644
> --- a/mm/mremap.c
> +++ b/mm/mremap.c
> @@ -634,10 +634,10 @@ static struct vm_area_struct *vma_to_resize(unsigned long addr,
> 	unsigned long *p)
> {
> 	struct mm_struct *mm = current->mm;
> -	struct vm_area_struct *vma = find_vma(mm, addr);
> +	struct vm_area_struct *vma = vma_lookup(mm, addr);
> 	unsigned long pgoff;

Nit, but could the vma_lookup() call be separate from the declaration
of vma?

	vma = find_vma();
> -	if (!vma || vma->vm_start > addr)
> +	if (!vma)
> 		return ERR_PTR(-EFAULT);

Thanks,
Davidlohr