# \[PATCH 01/24\] netmem: Create new type

- From: Matthew Wilcox (Oracle) \<willy@infradead.org\>
- Date: 2022-11-30 22:08:48 
- List: netdev
- Page: https://ratatoskr.run/netdev/2022/11/6520161
- Thread: https://ratatoskr.run/netdev/2022/11/6520146/t.md

```text
As part of simplifying struct page, create a new netmem type which
mirrors the page_pool members in struct page.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 include/net/page_pool.h | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/include/net/page_pool.h b/include/net/page_pool.h
index 813c93499f20..af6ff8c302a0 100644
--- a/include/net/page_pool.h
+++ b/include/net/page_pool.h
@@ -50,6 +50,47 @@
 				 PP_FLAG_DMA_SYNC_DEV |\
 				 PP_FLAG_PAGE_FRAG)
 
+/* page_pool used by netstack */
+struct netmem {
+	unsigned long flags;		/* Page flags */
+	/**
+	 * @pp_magic: magic value to avoid recycling non
+	 * page_pool allocated pages.
+	 */
+	unsigned long pp_magic;
+	struct page_pool *pp;
+	unsigned long _pp_mapping_pad;
+	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;
+	};
+	atomic_t _mapcount;
+	atomic_t _refcount;
+};
+
+#define NETMEM_MATCH(pg, nm)						\
+	static_assert(offsetof(struct page, pg) == offsetof(struct netmem, nm))
+NETMEM_MATCH(flags, flags);
+NETMEM_MATCH(lru, pp_magic);
+NETMEM_MATCH(pp, pp);
+NETMEM_MATCH(mapping, _pp_mapping_pad);
+NETMEM_MATCH(dma_addr, dma_addr);
+NETMEM_MATCH(dma_addr_upper, dma_addr_upper);
+NETMEM_MATCH(pp_frag_count, pp_frag_count);
+NETMEM_MATCH(_mapcount, _mapcount);
+NETMEM_MATCH(_refcount, _refcount);
+#undef NETMEM_MATCH
+static_assert(sizeof(struct netmem) <= sizeof(struct page));
+
 /*
  * Fast allocation side cache array/stack
  *
-- 
2.35.1

```