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

From: Christoph Hellwig
Date: Tue Jun 25 2019 - 03:44:28 EST

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?

Actually.. I we reorder this we'd need to to duplicate a few things
due to the zero/negative length checking. Given the feedback from
Khalid I'd thus rather skip the reorder for now. If we have a good
reason we could add it back, but it would be a bit involved.