improve use_mm / unuse_mm v2

[Jens Axboe]

On 4/15/20 11:31 PM, Christoph Hellwig wrote:
> Hi all,
> 
> this series improves the use_mm / unuse_mm interface by better
> documenting the assumptions, and my taking the set_fs manipulations
> spread over the callers into the core API.
> 
> Changes since v1:
>  - drop a few patches
>  - fix a comment typo
>  - cover the newly merged use_mm/unuse_mm caller in vfio

You can add my reviewed-by/tested-by to the patches, passes the
io_uring regression tests.

-- 
Jens Axboe