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

From: Christoph Hellwig <[email-masked]>
Date: Tue, 25 Jun 2019 09:41:08 +0200

On Fri, Jun 21, 2019 at 10:39:11AM -0300, Jason Gunthorpe wrote:
> 
> Hmm, this function, and the other, goes on to do:
> 
>         if (unlikely(!access_ok((void __user *)start, len)))
>                 return 0;
> 
> and I thought that access_ok takes in the tagged pointer?
> 
> How about re-order it a bit?

The patch doesn't really work as-as an misses the main
get_user_pages_fast fast path, but I'll add something equivalent.