From 89ade7c7306508f46b811cd43960eaed88e0e1dd Mon Sep 17 00:00:00 2001 From: Byungchul Park Date: Mon, 21 Jul 2025 11:18:26 +0900 Subject: netmem, mlx4: access ->pp_ref_count through netmem_desc instead of page To eliminate the use of struct page in page pool, the page pool users should use netmem descriptor and APIs instead. Make mlx4 access ->pp_ref_count through netmem_desc instead of page. While at it, add a helper, pp_page_to_nmdesc() and __pp_page_to_nmdesc(), that can be used to get netmem_desc from page only if it's a pp page. For now that netmem_desc overlays on page, it can be achieved by just casting, and use macro and _Generic to cover const casting as well. Plus, change page_pool_page_is_pp() to check for 'const struct page *' instead of 'struct page *' since it doesn't modify data and additionally covers const type. Signed-off-by: Byungchul Park Link: https://patch.msgid.link/20250721021835.63939-4-byungchul@sk.com Signed-off-by: Jakub Kicinski --- include/net/netmem.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'include/net') diff --git a/include/net/netmem.h b/include/net/netmem.h index 097bc74d9555..f7dacc9e75fd 100644 --- a/include/net/netmem.h +++ b/include/net/netmem.h @@ -285,6 +285,23 @@ static inline struct net_iov *__netmem_clear_lsb(netmem_ref netmem) return (struct net_iov *)((__force unsigned long)netmem & ~NET_IOV); } +/* XXX: How to extract netmem_desc from page must be changed, once + * netmem_desc no longer overlays on page and will be allocated through + * slab. + */ +#define __pp_page_to_nmdesc(p) (_Generic((p), \ + const struct page * : (const struct netmem_desc *)(p), \ + struct page * : (struct netmem_desc *)(p))) + +/* CAUTION: Check if the page is a pp page before calling this helper or + * know it's a pp page. + */ +#define pp_page_to_nmdesc(p) \ +({ \ + DEBUG_NET_WARN_ON_ONCE(!page_pool_page_is_pp(p)); \ + __pp_page_to_nmdesc(p); \ +}) + /** * __netmem_get_pp - unsafely get pointer to the &page_pool backing @netmem * @netmem: netmem reference to get the pointer from -- cgit v1.2.3