From patchwork Thu Oct 28 13:18:04 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxime Chevallier X-Patchwork-Id: 12590123 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9FF99C433F5 for ; Thu, 28 Oct 2021 13:18:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 79CCE61056 for ; Thu, 28 Oct 2021 13:18:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230216AbhJ1NUg (ORCPT ); Thu, 28 Oct 2021 09:20:36 -0400 Received: from relay12.mail.gandi.net ([217.70.178.232]:53431 "EHLO relay12.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229641AbhJ1NUf (ORCPT ); Thu, 28 Oct 2021 09:20:35 -0400 Received: (Authenticated sender: maxime.chevallier@bootlin.com) by relay12.mail.gandi.net (Postfix) with ESMTPSA id 37921200021; Thu, 28 Oct 2021 13:18:05 +0000 (UTC) From: Maxime Chevallier To: davem@davemloft.net, Russell King , Hideaki YOSHIFUJI , David Ahern , Jakub Kicinski , Antoine Tenart Cc: Maxime Chevallier , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, thomas.petazzoni@bootlin.com Subject: [PATCH net-next v2] net: ipconfig: Release the rtnl_lock while waiting for carrier Date: Thu, 28 Oct 2021 15:18:04 +0200 Message-Id: <20211028131804.413243-1-maxime.chevallier@bootlin.com> X-Mailer: git-send-email 2.25.4 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org While waiting for a carrier to come on one of the netdevices, some devices will require to take the rtnl lock at some point to fully initialize all parts of the link. That's the case for SFP, where the rtnl is taken when a module gets detected. This prevents mounting an NFS rootfs over an SFP link. This means that while ipconfig waits for carriers to be detected, no SFP modules can be detected in the meantime, it's only detected after ipconfig times out. This commit releases the rtnl_lock while waiting for the carrier to come up, and re-takes it to check the for the init device and carrier status. Signed-off-by: Maxime Chevallier --- v2: - Following Antoine's review, release the lock earlier and only explicitely protect the for_each_netdev loop - Rebased and targeted the patch towards net-next - Dropped the Fixes tag net/ipv4/ipconfig.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c index 816d8aad5a68..9d41d5d5cd1e 100644 --- a/net/ipv4/ipconfig.c +++ b/net/ipv4/ipconfig.c @@ -262,6 +262,11 @@ static int __init ic_open_devs(void) dev->name, able, d->xid); } } + /* Devices with a complex topology like SFP ethernet interfaces needs + * the rtnl_lock at init. The carrier wait-loop must therefore run + * without holding it. + */ + rtnl_unlock(); /* no point in waiting if we could not bring up at least one device */ if (!ic_first_dev) @@ -274,9 +279,13 @@ static int __init ic_open_devs(void) msecs_to_jiffies(carrier_timeout * 1000))) { int wait, elapsed; + rtnl_lock(); for_each_netdev(&init_net, dev) - if (ic_is_init_dev(dev) && netif_carrier_ok(dev)) + if (ic_is_init_dev(dev) && netif_carrier_ok(dev)) { + rtnl_unlock(); goto have_carrier; + } + rtnl_unlock(); msleep(1); @@ -289,7 +298,6 @@ static int __init ic_open_devs(void) next_msg = jiffies + msecs_to_jiffies(20000); } have_carrier: - rtnl_unlock(); *last = NULL;