Hi Matthew,
On Thu, Feb 07, 2019 at 07:07:45AM -0800, Matthew Wilcox wrote:
> On Thu, Feb 07, 2019 at 04:36:36PM +0200, Ilias Apalodimas wrote:
> > +/* Until we can update struct-page, have a shadow struct-page, that
> > + * include our use-case
> > + * Used to store retrieve dma addresses from network drivers.
> > + * Never access this directly, use helper functions provided
> > + * page_pool_get_dma_addr()
> > + */
>
> Huh? Why not simply:
>
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index 2c471a2c43fa..2495a93ad90c 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -28,6 +28,10 @@ struct address_space;
> struct mem_cgroup;
> struct hmm;
>
> +struct page_pool {
> + dma_addr_t dma_addr;
> +};
> +
> /*
> * Each physical page in the system has a struct page associated with
> * it to keep track of whatever it is we are using the page for at the
> @@ -77,6 +81,7 @@ struct page {
> * avoid collision and false-positive PageTail().
> */
> union {
> + struct page_pool pool;
> struct { /* Page cache and anonymous pages */
> /**
> * @lru: Pageout list, eg. active_list protected by
>
Well updating struct page is the final goal, hence the comment. I am mostly
looking for opinions here since we are trying to store dma addresses which are
irrelevant to pages. Having dma_addr_t definitions in mm-related headers is a
bit controversial isn't it ? If we can add that, then yes the code would look
better
Thanks
/Ilias
