From 7a4cd71fa4514cd85df39b3cf99da8142660cdcd Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 4 Feb 2026 05:30:23 +0000 Subject: net: add vlan_get_protocol_offset_inline() helper skb_protocol() is bloated, and forces slow stack canaries in many fast paths. Add vlan_get_protocol_offset_inline() which deals with the non-vlan common cases. __vlan_get_protocol_offset() is now out of line. It returns a vlan_type_depth struct to avoid stack canaries in callers. struct vlan_type_depth { __be16 type; u16 depth; }; $ scripts/bloat-o-meter -t vmlinux.old vmlinux.new add/remove: 0/2 grow/shrink: 0/22 up/down: 0/-6320 (-6320) Function old new delta vlan_get_protocol_dgram 61 59 -2 __pfx_skb_protocol 16 - -16 __vlan_get_protocol_offset 307 273 -34 tap_get_user 1374 1207 -167 ip_md_tunnel_xmit 1625 1452 -173 tap_sendmsg 940 753 -187 netif_skb_features 1079 866 -213 netem_enqueue 3017 2800 -217 vlan_parse_protocol 271 50 -221 tso_start 567 344 -223 fq_dequeue 1908 1685 -223 skb_network_protocol 434 205 -229 ip6_tnl_xmit 2639 2409 -230 br_dev_queue_push_xmit 474 236 -238 skb_protocol 258 - -258 packet_parse_headers 621 357 -264 __ip6_tnl_rcv 1306 1039 -267 skb_csum_hwoffload_help 515 224 -291 ip_tunnel_xmit 2635 2339 -296 sch_frag_xmit_hook 1582 1233 -349 bpf_skb_ecn_set_ce 868 457 -411 IP6_ECN_decapsulate 1297 768 -529 ip_tunnel_rcv 2121 1489 -632 ipip6_rcv 2572 1922 -650 Total: Before=24892803, After=24886483, chg -0.03% Signed-off-by: Eric Dumazet Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260204053023.1622775-1-edumazet@google.com Signed-off-by: Paolo Abeni --- net/packet/af_packet.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'net/packet') diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 494d628d10a5..a1005359085a 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -572,8 +572,9 @@ static __be16 vlan_get_protocol_dgram(const struct sk_buff *skb) __be16 proto = skb->protocol; if (unlikely(eth_type_vlan(proto))) - proto = __vlan_get_protocol_offset(skb, proto, - skb_mac_offset(skb), NULL); + proto = vlan_get_protocol_offset_inline(skb, proto, + skb_mac_offset(skb), + NULL); return proto; } -- cgit