RE: [Intel-wired-lan] [PATCH net-next 01/10] net: Document skb_metadata_set contract with the drivers

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From: Intel-wired-lan <redacted> On Behalf
Of Jakub Sitnicki via Intel-wired-lan
Sent: Saturday, January 10, 2026 10:05 PM
To: netdev@vger.kernel.org
Cc: David S. Miller <davem@davemloft.net>; Eric Dumazet
[off-list ref]; Jakub Kicinski [off-list ref]; Paolo Abeni
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Subject: [Intel-wired-lan] [PATCH net-next 01/10] net: Document
skb_metadata_set contract with the drivers

Prepare to copy XDP metadata into an skb extension chunk. To access
the metadata contents, we need to know where it is located. Document
the expectation - skb->data must point right past the metadata when
skb_metadata_set gets called.

Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
---
 include/linux/skbuff.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index

86737076101d..df001283076f 100644

--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h

@@ -4554,6 +4554,13 @@ static inline bool skb_metadata_differs(const

struct sk_buff *skb_a,
 	       true : __skb_metadata_differs(skb_a, skb_b, len_a);  }

+/**
+ * skb_metadata_set - Record packet metadata length.
+ * @skb: packet carrying the metadata
+ * @meta_len: number of bytes of metadata preceding skb->data
+ *
+ * Must be called when skb->data already points past the metadata
area.
+ */
 static inline void skb_metadata_set(struct sk_buff *skb, u8 meta_len)
{
 	skb_shinfo(skb)->meta_len = meta_len;

--
2.43.0