Re: [PATCH v2 06/13] mm/gup: add an assertion that the mmap lock is locked

[John Hubbard <jhubbard@nvidia.com>]

On 1/24/23 12:34, Jason Gunthorpe wrote:
> Since commit 5b78ed24e8ec ("mm/pagemap: add mmap_assert_locked()
> annotations to find_vma*()") we already have this assertion, it is just
> buried in find_vma():
> 
>   __get_user_pages_locked()
>    __get_user_pages()
>    find_extend_vma()
>     find_vma()
> 
> Also check it at the top of __get_user_pages_locked() as a form of
> documentation.
> 
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
>   mm/gup.c | 2 ++
>   1 file changed, 2 insertions(+)

Reviewed-by: John Hubbard <jhubbard@nvidia.com>

thanks,
-- 
John Hubbard
NVIDIA

> 
> diff --git a/mm/gup.c b/mm/gup.c
> index 4c236fb83dcd3e..de1a5c64fdfdcf 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -1360,6 +1360,8 @@ static __always_inline long __get_user_pages_locked(struct mm_struct *mm,
>   		must_unlock = true;
>   		*locked = 1;
>   	}
> +	else
> +		mmap_assert_locked(mm);
>   
>   	if (flags & FOLL_PIN)
>   		mm_set_has_pinned_flag(&mm->flags);