Re: [PATCH 06/25] mm: factor out a devm_request_free_mem_region helper

[Dan Williams]

On Mon, Jun 17, 2019 at 5:27 AM Christoph Hellwig <hch@xxxxxx> wrote:
>
> Keep the physical address allocation that hmm_add_device does with the
> rest of the resource code, and allow future reuse of it without the hmm
> wrapper.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
> Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>
> ---
>  include/linux/ioport.h |  2 ++
>  kernel/resource.c      | 39 +++++++++++++++++++++++++++++++++++++++
>  mm/hmm.c               | 33 ++++-----------------------------
>  3 files changed, 45 insertions(+), 29 deletions(-)
>
> diff --git a/include/linux/ioport.h b/include/linux/ioport.h
> index da0ebaec25f0..76a33ae3bf6c 100644
> --- a/include/linux/ioport.h
> +++ b/include/linux/ioport.h
> @@ -286,6 +286,8 @@ static inline bool resource_overlaps(struct resource *r1, struct resource *r2)
>         return (r1->start <= r2->end && r1->end >= r2->start);
>  }
>
> +struct resource *devm_request_free_mem_region(struct device *dev,
> +               struct resource *base, unsigned long size);

This appears to need a 'static inline' helper stub in the
CONFIG_DEVICE_PRIVATE=n case, otherwise this compile error triggers:

ld: mm/hmm.o: in function `hmm_devmem_add':
/home/dwillia2/git/linux/mm/hmm.c:1427: undefined reference to
`devm_request_free_mem_region'