From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: "David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Jesper Dangaard Brouer <hawk@kernel.org>,
Saeed Mahameed <saeedm@nvidia.com>,
Leon Romanovsky <leon@kernel.org>,
Tariq Toukan <tariqt@nvidia.com>,
Andrew Lunn <andrew+netdev@lunn.ch>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>,
Ilias Apalodimas <ilias.apalodimas@linaro.org>,
Simon Horman <horms@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Mina Almasry <almasrymina@google.com>,
Yonglong Liu <liuyonglong@huawei.com>,
Yunsheng Lin <linyunsheng@huawei.com>,
Pavel Begunkov <asml.silence@gmail.com>,
Matthew Wilcox <willy@infradead.org>
Cc: netdev@vger.kernel.org, bpf@vger.kernel.org,
linux-rdma@vger.kernel.org, linux-mm@kvack.org,
"Toke Høiland-Jørgensen" <toke@redhat.com>
Subject: [PATCH net-next v9 1/2] page_pool: Move pp_magic check into helper functions
Date: Wed, 09 Apr 2025 12:41:36 +0200 [thread overview]
Message-ID: <20250409-page-pool-track-dma-v9-1-6a9ef2e0cba8@redhat.com> (raw)
In-Reply-To: <20250409-page-pool-track-dma-v9-0-6a9ef2e0cba8@redhat.com>
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 <almasrymina@google.com>
Tested-by: Yonglong Liu <liuyonglong@huawei.com>
Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
---
drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c | 4 ++--
include/linux/mm.h | 20 ++++++++++++++++++++
mm/page_alloc.c | 8 ++------
net/core/netmem_priv.h | 5 +++++
net/core/skbuff.c | 16 ++--------------
net/core/xdp.c | 4 ++--
6 files changed, 33 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/linux/mm.h b/include/linux/mm.h
index b7f13f087954bdccfe1e263d39a59bfd1d738ab6..56c47f4a38ca491b2457b46660782ebe04c30046 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -4248,4 +4248,24 @@ int arch_lock_shadow_stack_status(struct task_struct *t, unsigned long status);
#define VM_SEALED_SYSMAP VM_NONE
#endif
+/* 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
+
+#ifdef CONFIG_PAGE_POOL
+static inline bool page_pool_page_is_pp(struct page *page)
+{
+ return (page->pp_magic & PP_MAGIC_MASK) == PP_SIGNATURE;
+}
+#else
+static inline bool page_pool_page_is_pp(struct page *page)
+{
+ return false;
+}
+#endif
+
#endif /* _LINUX_MM_H */
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index fd6b865cb1abfbd3d2ebd67cdaa5f86d92a62e14..a18340b3221835bc81a4db058e5b655575ef665c 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -897,9 +897,7 @@ 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;
@@ -926,10 +924,8 @@ 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);
--
2.49.0
next prev parent reply other threads:[~2025-04-09 10:41 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-09 10:41 [PATCH net-next v9 0/2] Fix late DMA unmap crash for page pool Toke Høiland-Jørgensen
2025-04-09 10:41 ` Toke Høiland-Jørgensen [this message]
2025-04-10 1:15 ` [PATCH net-next v9 1/2] page_pool: Move pp_magic check into helper functions Zi Yan
2025-04-10 10:21 ` Toke Høiland-Jørgensen
2025-04-09 10:41 ` [PATCH net-next v9 2/2] page_pool: Track DMA-mapped pages and unmap them when destroying the pool Toke Høiland-Jørgensen
2025-06-11 16:35 ` Breno Leitao
2025-06-11 20:12 ` Jakub Kicinski
2025-06-12 7:25 ` Toke Høiland-Jørgensen
2025-06-12 14:05 ` Jakub Kicinski
2025-06-13 8:41 ` Toke Høiland-Jørgensen
2025-06-13 15:02 ` Jakub Kicinski
2025-06-20 11:01 ` Pedro Falcato
2025-04-15 0:30 ` [PATCH net-next v9 0/2] Fix late DMA unmap crash for page pool patchwork-bot+netdevbpf
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