[PATCH net-next v5 1/2] page_pool: Move pp_magic check into helper functions
From: Toke Høiland-Jørgensen <hidden>
Date: 2025-03-28 12:19:29
Also in:
bpf, linux-mm, linux-rdma
Subsystem:
mellanox mlx5 core vpi driver, memory management, memory management - page allocator, networking drivers, networking [general], page pool, the rest, xdp (express data path) · Maintainers:
Saeed Mahameed, Leon Romanovsky, Tariq Toukan, Mark Bloch, Andrew Morton, Vlastimil Babka, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Jesper Dangaard Brouer, Ilias Apalodimas, Linus Torvalds, Alexei Starovoitov, Daniel Borkmann, David S. Miller, John Fastabend
Since we are about to stash some more information into the pp_magic field, let's move the magic signature checks into a pair of helper functions so it can be changed in one place. Reviewed-by: Mina Almasry <redacted> Tested-by: Yonglong Liu <redacted> Acked-by: Jesper Dangaard Brouer <hawk@kernel.org> Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Signed-off-by: Toke Høiland-Jørgensen <redacted> --- drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c | 4 ++-- include/net/page_pool/types.h | 18 ++++++++++++++++++ mm/page_alloc.c | 9 +++------ net/core/netmem_priv.h | 5 +++++ net/core/skbuff.c | 16 ++-------------- net/core/xdp.c | 4 ++-- 6 files changed, 32 insertions(+), 24 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
index f803e1c93590068d3a7829b0683be4af019266d1..5ce1b463b7a8dd7969e391618658d66f6e836cc1 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c@@ -707,8 +707,8 @@ static void mlx5e_free_xdpsq_desc(struct mlx5e_xdpsq *sq, xdpi = mlx5e_xdpi_fifo_pop(xdpi_fifo); page = xdpi.page.page; - /* No need to check ((page->pp_magic & ~0x3UL) == PP_SIGNATURE) - * as we know this is a page_pool page. + /* No need to check page_pool_page_is_pp() as we + * know this is a page_pool page. */ page_pool_recycle_direct(page->pp, page); } while (++n < num);
diff --git a/include/net/page_pool/types.h b/include/net/page_pool/types.h
index 36eb57d73abc6cfc601e700ca08be20fb8281055..df0d3c1608929605224feb26173135ff37951ef8 100644
--- a/include/net/page_pool/types.h
+++ b/include/net/page_pool/types.h@@ -54,6 +54,14 @@ struct pp_alloc_cache { netmem_ref cache[PP_ALLOC_CACHE_SIZE]; }; +/* Mask used for checking in page_pool_page_is_pp() below. page->pp_magic is + * OR'ed with PP_SIGNATURE after the allocation in order to preserve bit 0 for + * the head page of compound page and bit 1 for pfmemalloc page. + * page_is_pfmemalloc() is checked in __page_pool_put_page() to avoid recycling + * the pfmemalloc page. + */ +#define PP_MAGIC_MASK ~0x3UL + /** * struct page_pool_params - page pool parameters * @fast: params accessed frequently on hotpath
@@ -264,6 +272,11 @@ void page_pool_destroy(struct page_pool *pool); void page_pool_use_xdp_mem(struct page_pool *pool, void (*disconnect)(void *), const struct xdp_mem_info *mem); void page_pool_put_netmem_bulk(netmem_ref *data, u32 count); + +static inline bool page_pool_page_is_pp(struct page *page) +{ + return (page->pp_magic & PP_MAGIC_MASK) == PP_SIGNATURE; +} #else static inline void page_pool_destroy(struct page_pool *pool) {
@@ -278,6 +291,11 @@ static inline void page_pool_use_xdp_mem(struct page_pool *pool, static inline void page_pool_put_netmem_bulk(netmem_ref *data, u32 count) { } + +static inline bool page_pool_page_is_pp(struct page *page) +{ + return false; +} #endif void page_pool_put_unrefed_netmem(struct page_pool *pool, netmem_ref netmem,
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 542d25f77be80304b731411ffd29b276ee13be0c..3535ee76afe946cbb042ecbce603bdbedc9233b9 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c@@ -55,6 +55,7 @@ #include <linux/delayacct.h> #include <linux/cacheinfo.h> #include <linux/pgalloc_tag.h> +#include <net/page_pool/types.h> #include <asm/div64.h> #include "internal.h" #include "shuffle.h"
@@ -872,9 +873,7 @@ static inline bool page_expected_state(struct page *page, #ifdef CONFIG_MEMCG page->memcg_data | #endif -#ifdef CONFIG_PAGE_POOL - ((page->pp_magic & ~0x3UL) == PP_SIGNATURE) | -#endif + page_pool_page_is_pp(page) | (page->flags & check_flags))) return false;
@@ -901,10 +900,8 @@ static const char *page_bad_reason(struct page *page, unsigned long flags) if (unlikely(page->memcg_data)) bad_reason = "page still charged to cgroup"; #endif -#ifdef CONFIG_PAGE_POOL - if (unlikely((page->pp_magic & ~0x3UL) == PP_SIGNATURE)) + if (unlikely(page_pool_page_is_pp(page))) bad_reason = "page_pool leak"; -#endif return bad_reason; }
diff --git a/net/core/netmem_priv.h b/net/core/netmem_priv.h
index 7eadb8393e002fd1cc2cef8a313d2ea7df76f301..f33162fd281c23e109273ba09950c5d0a2829bc9 100644
--- a/net/core/netmem_priv.h
+++ b/net/core/netmem_priv.h@@ -18,6 +18,11 @@ static inline void netmem_clear_pp_magic(netmem_ref netmem) __netmem_clear_lsb(netmem)->pp_magic = 0; } +static inline bool netmem_is_pp(netmem_ref netmem) +{ + return (netmem_get_pp_magic(netmem) & PP_MAGIC_MASK) == PP_SIGNATURE; +} + static inline void netmem_set_pp(netmem_ref netmem, struct page_pool *pool) { __netmem_clear_lsb(netmem)->pp = pool;
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 6cbf77bc61fce74c934628fd74b3a2cb7809e464..74a2d886a35b518d55b6d3cafcb8442212f9beee 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c@@ -893,11 +893,6 @@ static void skb_clone_fraglist(struct sk_buff *skb) skb_get(list); } -static bool is_pp_netmem(netmem_ref netmem) -{ - return (netmem_get_pp_magic(netmem) & ~0x3UL) == PP_SIGNATURE; -} - int skb_pp_cow_data(struct page_pool *pool, struct sk_buff **pskb, unsigned int headroom) {
@@ -995,14 +990,7 @@ bool napi_pp_put_page(netmem_ref netmem) { netmem = netmem_compound_head(netmem); - /* page->pp_magic is OR'ed with PP_SIGNATURE after the allocation - * in order to preserve any existing bits, such as bit 0 for the - * head page of compound page and bit 1 for pfmemalloc page, so - * mask those bits for freeing side when doing below checking, - * and page_is_pfmemalloc() is checked in __page_pool_put_page() - * to avoid recycling the pfmemalloc page. - */ - if (unlikely(!is_pp_netmem(netmem))) + if (unlikely(!netmem_is_pp(netmem))) return false; page_pool_put_full_netmem(netmem_get_pp(netmem), netmem, false);
@@ -1042,7 +1030,7 @@ static int skb_pp_frag_ref(struct sk_buff *skb) for (i = 0; i < shinfo->nr_frags; i++) { head_netmem = netmem_compound_head(shinfo->frags[i].netmem); - if (likely(is_pp_netmem(head_netmem))) + if (likely(netmem_is_pp(head_netmem))) page_pool_ref_netmem(head_netmem); else page_ref_inc(netmem_to_page(head_netmem));
diff --git a/net/core/xdp.c b/net/core/xdp.c
index f86eedad586a77eb63a96a85aa6d068d3e94f077..0ba73943c6eed873b3d1c681b3b9a802b590f2d9 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c@@ -437,8 +437,8 @@ void __xdp_return(netmem_ref netmem, enum xdp_mem_type mem_type, netmem = netmem_compound_head(netmem); if (napi_direct && xdp_return_frame_no_direct()) napi_direct = false; - /* No need to check ((page->pp_magic & ~0x3UL) == PP_SIGNATURE) - * as mem->type knows this a page_pool page + /* No need to check netmem_is_pp() as mem->type knows this a + * page_pool page */ page_pool_put_full_netmem(netmem_get_pp(netmem), netmem, napi_direct);
--
2.48.1