From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4AD0F263F4A; Thu, 4 Jun 2026 22:55:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780613738; cv=none; b=OTRWBNB9ZC6Bg1vYi3ySXMolBzV9wMHRUkcKfJZcshxN0yEwNqq0jvUrEKmLdSVj/Hv5WBjZCSEys4S2lXn2YuvhZGyf8HJIaQNCLaRVRvaUUbHiXzag2vlK1BUpOmA1AiYEmBMiaC6hCTCnOulxtIV4mIRMXW+dOO6m0FIyM08= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780613738; c=relaxed/simple; bh=HcZsm+qYr6MG1H0x7EN55ovk4ALF/9RpoJUOgpbJrgM=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=b5lAL5cUERHuBuU9eBqNPkAfq/kS2q1xdnIahXDEyYd3syVInGbZ1UYcaWBXjQYPv1XLlmgL9VIW3br+195yetZLJungdM29DcYTpkWDUf/VoezMN2k52C8KV0/PeZeukY5fSWstTSFeG+BXyEkIeX9C/fmRDNvJ9gpcZOcrlBU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gRPL097j; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gRPL097j" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1F0551F00893; Thu, 4 Jun 2026 22:55:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780613736; bh=v+E88Z5ofHG6vsKwXAZCwJwlTj2po7duBoxSzzzG9TY=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=gRPL097jOZ/0aH7fFsTdVSnTrxJmt62ZpGLgdPyXukAJahnGFbMZES7EEzhzL1xLO wYXy5tP0iZ1r8T8f/fGVkI6UH9TXGIfYzws5s2JIoEHKqJfy/vy98NcGj5YRpqCD7w v2FNFmW0Km1euMrrpTj0oUiR2104vJukTfsW3XwYVv3HLw/X8AqtNhUHQc32iok9dw To6SkGkxhLkN79s0prMXDioc1Bd3jkARL5eB/f7CKfby6WMPoiOjWzwhGLCzdQqMd8 hYJ7e8F+tSvfJ6gD74VDUk3NPtWrqcOoduLWUvoXxCLYMHW5yml0+F1F8vWu4jZE8e n6FJ7CO4p4rbg== Date: Thu, 4 Jun 2026 15:55:35 -0700 From: Jakub Kicinski To: Ido Schimmel Cc: David Gibson , Stefano Brivio , Fernando Fernandez Mancera , netdev@vger.kernel.org, yuhuang@redhat.com, justin.iurman@gmail.com, horms@kernel.org, pabeni@redhat.com, edumazet@google.com, davem@davemloft.net, dsahern@kernel.org, Chris Adams , Beniamino Galvani , Thorsten Leemhuis , Andrew Lunn , ihuguet@redhat.com, regressions@lists.linux.dev Subject: Re: IPv6 address insertion order (was Re: [PATCH net v2] Revert "ipv6: preserve insertion order for same-scope addresses") Message-ID: <20260604155535.4662a95b@kernel.org> In-Reply-To: <20260604183909.GA877115@shredder> References: <20260529112357.5079-1-fmancera@suse.de> <20260529134045.56330243@elisabeth> <20260602132118.GA508395@shredder> <20260603074717.GA569921@shredder> <20260603174538.5454bb93@elisabeth> <20260604183909.GA877115@shredder> Precedence: bulk X-Mailing-List: regressions@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 4 Jun 2026 21:39:09 +0300 Ido Schimmel wrote: > Given the above, my preference would be #3 -> #2 -> #1. The first two > options expose the same capability to user space, so #1 doesn't buy us > anything over #2, except a bit less code, but we risk introducing a > regression. > > Between #2 and #3, production software can't drop the fallback even if > we implement #2, yet #2 requires us to maintain uAPI forever. I think we > should accept that the divergence between IPv4 and IPv6 is not ideal, > but at least it's predictable and dependable (Fernando is working on a > ksft and documentation). +1 to this, FWIW