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Tue, 10 Mar 2026 15:36:43 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id uHUkEYs6sGlKXwAAD6G6ig (envelope-from ); Tue, 10 Mar 2026 15:36:43 +0000 From: Fernando Fernandez Mancera To: netdev@vger.kernel.org Cc: rbm@suse.com, Fernando Fernandez Mancera , davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, dsahern@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 00/10 net-next v2] Convert CONFIG_IPV6 to built-in and remove stubs Date: Tue, 10 Mar 2026 16:34:23 +0100 Message-ID: <20260310153506.5181-1-fmancera@suse.de> X-Mailer: git-send-email 2.51.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Score: -2.80 X-Spam-Level: X-Spamd-Result: default: False [-2.80 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; MID_CONTAINS_FROM(1.00)[]; R_MISSING_CHARSET(0.50)[]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; TO_MATCH_ENVRCPT_ALL(0.00)[]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; FROM_HAS_DN(0.00)[]; MIME_TRACE(0.00)[0:+]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:mid]; FUZZY_RATELIMITED(0.00)[rspamd.com]; RCPT_COUNT_SEVEN(0.00)[10]; RCVD_COUNT_TWO(0.00)[2]; FROM_EQ_ENVFROM(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; TO_DN_SOME(0.00)[]; RCVD_TLS_ALL(0.00)[] X-Spam-Flag: NO Historically, the Linux kernel has supported compiling the IPv6 stack as a loadable module. While this made sense in the early days of IPv6 adoption, modern deployments and distributions overwhelmingly either build IPv6 directly into the kernel (CONFIG_IPV6=y) or disable it entirely (CONFIG_IPV6=n). The modular IPv6 use-case offers image size and memory savings for specific setups, this benefit is outweighed by the architectural burden it imposes on the subsystems on implementation and maintenance. To allow core networking, BPF, Netfilter, and various device drivers to safely interact with a potentially unloaded IPv6 module, the kernel relies on indirect call structures like ipv6_stub, ipv6_bpf_stub, and nf_ipv6_ops, along with dynamic RCU registrations for things like ICMPv6 senders. This patch series addresses this by changing CONFIG_IPV6 from a tristate to a boolean, enforcing that IPv6 is either built-in or disabled. This allows us to completely rip out the stub infrastructures and safely replace them with direct function calls. The bloat-o-meter report the following results for m68k, arm64, x86_64 defconfig. m68k (keep on mind that CONFIG_IPV6 is disabled now): add/remove: 65/938 grow/shrink: 36/254 up/down: 3022/-49692 (-46670) arm64: add/remove: 1251/265 grow/shrink: 81/46 up/down: 448740/-71519 (377221) x86_64: add/remove: 62/98 grow/shrink: 10/39 up/down: 2497/-4357 (-1860) All the patches has been independently build tested. With allmodconfig and allmodconfig + CONFIG_IPV6=n. In addition, net selftest has been run against them on virtme-ng. The series applied as a whole as been tested with allyesconfig and also allyesconfig + CONFIG_IPV6=n but not all patches has been independently tested this way. This will like need to wait for [1] and [2] to be applied to avoid conflicts from net tree and rebased in top of them. [1] https://lore.kernel.org/netdev/20260307-net-nd_tbl_fixes-v4-0-e2677e85628c@suse.com/ [2] https://lore.kernel.org/netdev/20260308032304.1841198-1-kuniyu@google.com/ Fernando Fernandez Mancera (10): ipv6: convert CONFIG_IPV6 to built-in only and clean up Kconfigs ipv6: replace IS_BUILTIN(CONFIG_IPV6) with IS_ENABLED(CONFIG_IPV6) ipv6: remove dynamic ICMPv6 sender registration infrastructure ipv6: prepare headers for ipv6_stub removal drivers: net: drop ipv6_stub usage and use direct function calls ipv4: drop ipv6_stub usage and use direct function calls net: convert remaining ipv6_stub users to direct function calls bpf: remove ipv6_bpf_stub completely and use direct function calls ipv6: remove ipv6_stub infrastructure completely netfilter: remove nf_ipv6_ops and use direct function calls arch/arm64/configs/defconfig | 2 +- arch/m68k/configs/amiga_defconfig | 45 +------- arch/m68k/configs/apollo_defconfig | 46 +------- arch/m68k/configs/atari_defconfig | 45 +------- arch/m68k/configs/bvme6000_defconfig | 45 +------- arch/m68k/configs/hp300_defconfig | 47 +------- arch/m68k/configs/mac_defconfig | 45 +------- arch/m68k/configs/multi_defconfig | 45 +------- arch/m68k/configs/mvme147_defconfig | 45 +------- arch/m68k/configs/mvme16x_defconfig | 45 +------- arch/m68k/configs/q40_defconfig | 45 +------- arch/m68k/configs/sun3_defconfig | 45 +------- arch/m68k/configs/sun3x_defconfig | 45 +------- drivers/infiniband/Kconfig | 1 - drivers/infiniband/core/addr.c | 3 +- drivers/infiniband/hw/ocrdma/Kconfig | 2 +- drivers/infiniband/sw/rxe/rxe_net.c | 6 +- drivers/infiniband/ulp/ipoib/Kconfig | 2 +- drivers/net/Kconfig | 9 -- drivers/net/ethernet/broadcom/Kconfig | 2 +- drivers/net/ethernet/chelsio/Kconfig | 2 +- .../mellanox/mlx5/core/en/rep/neigh.c | 12 ++- .../ethernet/mellanox/mlx5/core/en/tc_tun.c | 3 +- .../mellanox/mlx5/core/en/tc_tun_encap.c | 2 +- .../mellanox/mlx5/core/en_accel/ipsec.c | 1 - .../net/ethernet/mellanox/mlx5/core/en_rep.c | 1 - .../net/ethernet/mellanox/mlx5/core/en_tc.c | 1 - drivers/net/ethernet/mellanox/mlxsw/Kconfig | 1 - .../ethernet/mellanox/mlxsw/spectrum_router.c | 9 +- .../ethernet/mellanox/mlxsw/spectrum_span.c | 3 +- drivers/net/ethernet/netronome/Kconfig | 1 - .../ethernet/netronome/nfp/flower/action.c | 2 +- .../netronome/nfp/flower/tunnel_conf.c | 9 +- drivers/net/ethernet/sfc/tc_counters.c | 2 +- drivers/net/ethernet/sfc/tc_encap_actions.c | 5 +- drivers/net/geneve.c | 1 - drivers/net/gtp.c | 2 +- drivers/net/ovpn/peer.c | 3 +- drivers/net/ovpn/udp.c | 3 +- drivers/net/usb/cdc_mbim.c | 17 +-- drivers/net/vrf.c | 3 +- drivers/net/vxlan/vxlan_core.c | 11 +- drivers/net/vxlan/vxlan_multicast.c | 6 +- drivers/net/wireguard/socket.c | 3 +- drivers/net/wireless/intel/ipw2x00/ipw2100.c | 2 +- drivers/scsi/bnx2fc/Kconfig | 1 - drivers/scsi/bnx2i/Kconfig | 1 - drivers/scsi/cxgbi/cxgb3i/Kconfig | 2 +- drivers/scsi/cxgbi/cxgb4i/Kconfig | 2 +- fs/dlm/Kconfig | 2 +- fs/gfs2/Kconfig | 2 +- include/linux/icmpv6.h | 26 +---- include/linux/indirect_call_wrapper.h | 2 +- include/linux/netfilter_ipv6.h | 102 ++---------------- include/net/ip.h | 5 - include/net/ip6_fib.h | 34 +++++- include/net/ip6_route.h | 26 +++++ include/net/ipv6.h | 12 +++ include/net/ipv6_stubs.h | 102 ------------------ include/net/ndisc.h | 38 +++---- include/net/udp_tunnel.h | 3 +- net/bridge/Kconfig | 1 - net/bridge/br_arp_nd_proxy.c | 3 +- net/bridge/br_netfilter_hooks.c | 12 +-- net/bridge/br_netfilter_ipv6.c | 7 +- net/core/filter.c | 70 ++++++------ net/core/lwt_bpf.c | 10 +- net/ieee802154/6lowpan/tx.c | 2 +- net/ipv4/Kconfig | 9 +- net/ipv4/fib_semantics.c | 11 +- net/ipv4/icmp.c | 2 +- net/ipv4/nexthop.c | 21 ++-- net/ipv4/route.c | 2 +- net/ipv4/udp.c | 7 +- net/ipv6/Kconfig | 6 +- net/ipv6/addrconf.c | 10 +- net/ipv6/addrconf_core.c | 91 ---------------- net/ipv6/af_inet6.c | 69 ++---------- net/ipv6/icmp.c | 6 -- net/ipv6/ip6_fib.c | 10 +- net/ipv6/ip6_icmp.c | 46 +------- net/ipv6/ip6_offload.c | 4 +- net/ipv6/ip6_output.c | 5 +- net/ipv6/ip6_udp_tunnel.c | 3 +- net/ipv6/ndisc.c | 35 +++--- net/ipv6/netfilter.c | 48 --------- net/ipv6/route.c | 13 +-- net/l2tp/Kconfig | 1 - net/mpls/af_mpls.c | 3 +- net/netfilter/Kconfig | 8 -- net/netfilter/core.c | 3 - net/netfilter/nf_nat_masquerade.c | 21 +--- net/netfilter/nfnetlink_queue.c | 22 +++- net/netfilter/utils.c | 1 - net/openvswitch/actions.c | 3 +- net/rxrpc/Kconfig | 2 +- net/sched/sch_frag.c | 4 +- net/sctp/Kconfig | 1 - net/tipc/Kconfig | 1 - net/tipc/udp_media.c | 9 +- net/xfrm/espintcp.c | 5 +- net/xfrm/xfrm_nat_keepalive.c | 4 +- net/xfrm/xfrm_output.c | 3 +- 103 files changed, 328 insertions(+), 1301 deletions(-) delete mode 100644 include/net/ipv6_stubs.h -- 2.53.0