Re: [PATCH net-next v2 0/4] add frag page support in page pool

[Jesper Dangaard Brouer]

On 10/08/2021 16.01, Jakub Kicinski wrote:
> On Fri, 6 Aug 2021 10:46:18 +0800 Yunsheng Lin wrote:
> > enable skb's page frag recycling based on page pool in
> > hns3 drvier.
>
> Applied, thanks!

I had hoped to see more acks / reviewed-by before this got applied.
E.g. from MM-people as this patchset changes struct page and page_pool 
(that I'm marked as maintainer of).  And I would have appreciated an 
reviewed-by credit to/from Alexander as he did a lot of work in the RFC 
patchset for the split-page tricks.

p.s. I just returned from vacation today, and have not had time to 
review, sorry.

--Jesper

(relevant struct page changes for MM-people to review)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 52bbd2b..7f8ee09 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -103,11 +103,19 @@ struct page {
 			unsigned long pp_magic;
 			struct page_pool *pp;
 			unsigned long _pp_mapping_pad;
-			/**
-			 * @dma_addr: might require a 64-bit value on
-			 * 32-bit architectures.
-			 */
-			unsigned long dma_addr[2];
+			unsigned long dma_addr;
+			union {
+				/**
+				 * dma_addr_upper: might require a 64-bit
+				 * value on 32-bit architectures.
+				 */
+				unsigned long dma_addr_upper;
+				/**
+				 * For frag page support, not supported in
+				 * 32-bit architectures with 64-bit DMA.
+				 */
+				atomic_long_t pp_frag_count;
+			};
 		};
 		struct {	/* slab, slob and slub */