diff mbox series

[net-next,v9,1/2] page_pool: Move pp_magic check into helper functions

Message ID 20250409-page-pool-track-dma-v9-1-6a9ef2e0cba8@redhat.com (mailing list archive)
State New
Headers show
Series Fix late DMA unmap crash for page pool | expand

Commit Message

Toke Høiland-Jørgensen April 9, 2025, 10:41 a.m. UTC 
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(-)

Comments

Zi Yan April 10, 2025, 1:15 a.m. UTC | #1 
On Wed Apr 9, 2025 at 6:41 AM EDT, Toke Høiland-Jørgensen wrote:
> 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(-)
>

LGTM. Reviewed-by: Zi Yan <ziy@nvidia.com>
Toke Høiland-Jørgensen April 10, 2025, 10:21 a.m. UTC | #2 
"Zi Yan" <ziy@nvidia.com> writes:

> On Wed Apr 9, 2025 at 6:41 AM EDT, Toke Høiland-Jørgensen wrote:
>> 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(-)
>>
>
> LGTM. Reviewed-by: Zi Yan <ziy@nvidia.com>

Great, thanks!

-Toke
diff mbox series

Patch

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);