> This is the first step toward making Legacy IP optional. The option > defaults to y and currently has no effect — subsequent patches will use > it to guard IPv4 entry points.
The commit message says "The option defaults to y", but the Kconfig entry has no "default y" line. A bool without an explicit default is n in Kconfig, so LEGACY_IP will be disabled on any fresh config built with make defconfig or make olddefconfig. Later patches in this series (be2f051150f9, f04a0717c27d) add "depends on LEGACY_IP" to all IPv4-specific Kconfig symbols and guard IPv4 entry points in C code. With LEGACY_IP defaulting to n, those patches will silently disable IPv4 networking for any newly generated kernel configuration. Should the Kconfig entry include "default y" to match the stated intent? > diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig > index df922f9f5289..aef2c5349e62 100644 > --- a/net/ipv4/Kconfig > +++ b/net/ipv4/Kconfig > @@ -2,6 +2,17 @@ > # > # IP configuration > # > +config LEGACY_IP > + bool "The IPv4 protocol (Legacy IP)" > + help > + Support for IP version 4 (IPv4). > + > + Legacy IP is the protocol used by the early ARPANET, before IPv6 > + was standardised in the final decade of the 1900s. It should only > + be necessary these days to interoperate with legacy networks. > + > + If unsure, say N. The help text says "If unsure, say N." Combined with the missing default, this guides users to disable IPv4. If the intent is a backward-compatible introduction where IPv4 stays enabled unless explicitly turned off, this should probably be "If unsure, say Y." --- AI reviewed your patch. Please fix the bug or email reply why it's not a bug. See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md CI run summary: https://github.com/kernel-patches/bpf/actions/runs/23838411859
