From: Fernando Fernandez Mancera <fmancera@suse.de>
To: netdev@vger.kernel.org
Cc: rbm@suse.com, Fernando Fernandez Mancera <fmancera@suse.de>,
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 [thread overview]
Message-ID: <20260310153506.5181-1-fmancera@suse.de> (raw)
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
next reply other threads:[~2026-03-10 15:36 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-10 15:34 Fernando Fernandez Mancera [this message]
2026-03-10 15:34 ` [PATCH 01/10 net-next v2] ipv6: convert CONFIG_IPV6 to built-in only and clean up Kconfigs Fernando Fernandez Mancera
2026-03-12 3:02 ` Jakub Kicinski
2026-03-12 15:12 ` Fernando Fernandez Mancera
2026-03-12 16:05 ` Geert Uytterhoeven
2026-03-12 7:43 ` Geert Uytterhoeven
2026-03-16 15:44 ` Krzysztof Kozlowski
2026-03-10 15:34 ` [PATCH 02/10 net-next v2] ipv6: replace IS_BUILTIN(CONFIG_IPV6) with IS_ENABLED(CONFIG_IPV6) Fernando Fernandez Mancera
2026-03-10 15:34 ` [PATCH 03/10 net-next v2] ipv6: remove dynamic ICMPv6 sender registration infrastructure Fernando Fernandez Mancera
2026-03-10 15:34 ` [PATCH 04/10 net-next v2] ipv6: prepare headers for ipv6_stub removal Fernando Fernandez Mancera
2026-03-10 16:50 ` David Ahern
2026-03-10 15:34 ` [PATCH 05/10 net-next v2] drivers: net: drop ipv6_stub usage and use direct function calls Fernando Fernandez Mancera
2026-03-12 13:48 ` Jason A. Donenfeld
2026-03-13 10:54 ` Antonio Quartulli
2026-03-13 12:07 ` Edward Cree
2026-03-10 15:34 ` [PATCH 06/10 net-next v2] ipv4: " Fernando Fernandez Mancera
2026-03-10 15:34 ` [PATCH 07/10 net-next v2] net: convert remaining ipv6_stub users to " Fernando Fernandez Mancera
2026-03-10 15:34 ` [PATCH 08/10 net-next v2] bpf: remove ipv6_bpf_stub completely and use " Fernando Fernandez Mancera
2026-03-12 10:12 ` Daniel Borkmann
2026-03-10 15:34 ` [PATCH 09/10 net-next v2] ipv6: remove ipv6_stub infrastructure completely Fernando Fernandez Mancera
2026-03-10 15:34 ` [PATCH 10/10 net-next v2] netfilter: remove nf_ipv6_ops and use direct function calls Fernando Fernandez Mancera
2026-03-10 18:08 ` [PATCH 00/10 net-next v2] Convert CONFIG_IPV6 to built-in and remove stubs Ricardo B. Marlière
2026-03-12 3:01 ` Jakub Kicinski
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