Re: [PATCH 01/16] mm: use untagged_addr() for get_user_pages_fast addresses

[Khalid Aziz <khalid.aziz@oracle.com>]

On 6/11/19 8:40 AM, Christoph Hellwig wrote:
> This will allow sparc64 to override its ADI tags for
> get_user_pages and get_user_pages_fast.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---

Commit message is sparc64 specific but the goal here is to allow any
architecture with memory tagging to use this. So I would suggest
rewording the commit log. Other than that:

Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>

>  mm/gup.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/gup.c b/mm/gup.c
> index ddde097cf9e4..6bb521db67ec 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -2146,7 +2146,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
>  	unsigned long flags;
>  	int nr = 0;
>  
> -	start &= PAGE_MASK;
> +	start = untagged_addr(start) & PAGE_MASK;
>  	len = (unsigned long) nr_pages << PAGE_SHIFT;
>  	end = start + len;
>  
> @@ -2219,7 +2219,7 @@ int get_user_pages_fast(unsigned long start, int nr_pages,
>  	unsigned long addr, len, end;
>  	int nr = 0, ret = 0;
>  
> -	start &= PAGE_MASK;
> +	start = untagged_addr(start) & PAGE_MASK;
>  	addr = start;
>  	len = (unsigned long) nr_pages << PAGE_SHIFT;
>  	end = start + len;
>