# Re: \[PATCH v7 07/24\] IB/umem: use get\_user\_pages\_fast() to pin DMA pages

- From: Christoph Hellwig \<hch@infradead.org\>
- Date: 2019-11-21 08:09:57 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2019/11/167351
- Thread: https://ratatoskr.run/bpf/2019/11/167331/t.md

```text
On Wed, Nov 20, 2019 at 11:13:37PM -0800, John Hubbard wrote:
> And get rid of the mmap_sem calls, as part of that. Note
> that get_user_pages_fast() will, if necessary, fall back to
> __gup_longterm_unlocked(), which takes the mmap_sem as needed.
> 
> Reviewed-by: Jan Kara <jack@suse.cz>
> Reviewed-by: Jason Gunthorpe <redacted>
> Reviewed-by: Ira Weiny <redacted>
> Signed-off-by: John Hubbard <jhubbard@nvidia.com>

Looks fine,

Reviewed-by: Christoph Hellwig <hch@lst.de>

Jason, can you queue this up for 5.5 to reduce this patch stack a bit?
```