From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 26A3D1F8937; Tue, 17 Dec 2024 17:30:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734456640; cv=none; b=J9sd+dWWJVzXWWFxuQk7Jrfu/vvqMdZam47hz6rvAxTJcyA3P1p9oRGZnWHF/c2ZdDKeyHeLfGyJJSt7TzgluwQzjP4KYLOXor1GavOR9VeSlAJf1v2b9vAm85ioEKUdr+wbai+lOTsyYByXv8HAUF5WYQ+deRn2Da/BdRwWHBU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734456640; c=relaxed/simple; bh=48/LTCIBiGDH+ICxZ7p+9GVZJo9kXYupM8bvR2vyLhU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=H5rFiVe91mDGh0LhNmLpe0OL6kbgseycDAHwf91tnLPxgVeTOKrbVV+QSaWhbBidew0tQPPMDNXNeo734w0kS7bgevaCZAeW6Yim9X6Ucwqihjw3GvbjDYsD+4m88nronaj9xkaJocDLgvOhK0dOYFRGVzThw5RL2syB8IfO8z0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=qPyWsjmh; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="qPyWsjmh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A371C4AF0B; Tue, 17 Dec 2024 17:30:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1734456639; bh=48/LTCIBiGDH+ICxZ7p+9GVZJo9kXYupM8bvR2vyLhU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qPyWsjmhq80qHoQwQ8zq0qboL9KxWK99oJOV7U0JFBVeIzDKQC9Tmh8C5JfRA4Vvt BoAtRsXHZTJ9dXpQx3KiMhuIg/UNzkWQMB8kbUrN31TQldL39IJ9j9arLvC3DTefcv 3c5LuvOK4K2HTcp6JZKvEExhSwtzhJFZsnJHAMpA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Petr Machata , Ido Schimmel , David Ahern , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.12 121/172] Documentation: networking: Add a caveat to nexthop_compat_mode sysctl Date: Tue, 17 Dec 2024 18:07:57 +0100 Message-ID: <20241217170551.352900480@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241217170546.209657098@linuxfoundation.org> References: <20241217170546.209657098@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Petr Machata [ Upstream commit bbe4b41259a3e255a16d795486d331c1670b4e75 ] net.ipv4.nexthop_compat_mode was added when nexthop objects were added to provide the view of nexthop objects through the usual lens of the route UAPI. As nexthop objects evolved, the information provided through this lens became incomplete. For example, details of resilient nexthop groups are obviously omitted. Now that 16-bit nexthop group weights are a thing, the 8-bit UAPI cannot convey the >8-bit weight accurately. Instead of inventing workarounds for an obsolete interface, just document the expectations of inaccuracy. Fixes: b72a6a7ab957 ("net: nexthop: Increase weight to u16") Signed-off-by: Petr Machata Reviewed-by: Ido Schimmel Reviewed-by: David Ahern Link: https://patch.msgid.link/b575e32399ccacd09079b2a218255164535123bd.1733740749.git.petrm@nvidia.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- Documentation/networking/ip-sysctl.rst | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index eacf8983e230..dcbb6f6caf6d 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -2170,6 +2170,12 @@ nexthop_compat_mode - BOOLEAN understands the new API, this sysctl can be disabled to achieve full performance benefits of the new API by disabling the nexthop expansion and extraneous notifications. + + Note that as a backward-compatible mode, dumping of modern features + might be incomplete or wrong. For example, resilient groups will not be + shown as such, but rather as just a list of next hops. Also weights that + do not fit into 8 bits will show incorrectly. + Default: true (backward compat mode) fib_notify_on_flag_change - INTEGER -- 2.39.5