netdev - [PATCH RFC bpf-next 4/9] bpf: Make bpf_skb_vlan

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Message-Id: <20250929-skb-meta-rx-path-v1-4-de700a7ab1cb@cloudflare.com>
Date: Mon, 29 Sep 2025 16:09:09 +0200
From: Jakub Sitnicki <jakub@...udflare.com>
To: bpf@...r.kernel.org
Cc: netdev@...r.kernel.org, kernel-team@...udflare.com
Subject: [PATCH RFC bpf-next 4/9] bpf: Make bpf_skb_vlan_pop helper
 metadata-safe

Use the metadata-aware helper to move packet bytes after skb_pull(),
ensuring metadata remains valid after calling the BPF helper.

Signed-off-by: Jakub Sitnicki <jakub@...udflare.com>
---
 include/linux/if_vlan.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h
index afa5cc61a0fa..4ecc2509b0d4 100644
--- a/include/linux/if_vlan.h
+++ b/include/linux/if_vlan.h
@@ -738,9 +738,9 @@ static inline void vlan_remove_tag(struct sk_buff *skb, u16 *vlan_tci)
 
 	*vlan_tci = ntohs(vhdr->h_vlan_TCI);
 
-	memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
 	vlan_set_encap_proto(skb, vhdr);
 	__skb_pull(skb, VLAN_HLEN);
+	skb_postpull_data_move(skb, VLAN_HLEN, 2 * ETH_ALEN);
 }
 
 /**

-- 
2.43.0