On Mon, 11 Feb 2019 17:06:46 +0100 Jesper Dangaard Brouer <[email protected]>
wrote:
> The page_pool API is using page->private to store DMA addresses.
> As pointed out by David Miller we can't use that on 32-bit architectures
> with 64-bit DMA
>
> This patch adds a new dma_addr_t struct to allow storing DMA addresses
>
> ..
>
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -95,6 +95,14 @@ struct page {
> */
> unsigned long private;
> };
> + struct { /* page_pool used by netstack */
> + /**
> + * @dma_addr: Page_pool need to store DMA-addr, and
> + * cannot use @private, as DMA-mappings can be 64-bit
> + * even on 32-bit Architectures.
> + */
This comment is a bit awkward. The discussion about why it doesn't use
->private is uninteresting going forward and is more material for a
changelog.
How about
/**
* @dma_addr: page_pool requires a 64-bit value even on
* 32-bit architectures.
*/
Otherwise,
Acked-by: Andrew Morton <[email protected]>
