Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752426AbdLHIev (ORCPT ); Fri, 8 Dec 2017 03:34:51 -0500 Received: from mx2.suse.de ([195.135.220.15]:37614 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750910AbdLHIes (ORCPT ); Fri, 8 Dec 2017 03:34:48 -0500 Date: Fri, 8 Dec 2017 17:34:41 +0900 From: Benjamin Poirier To: Ben Hutchings Cc: Gabriel C , Christian Hesse , Jeff Kirsher , stable@vger.kernel.org, Lennart Sorensen , Aaron Brown , Amit Pundir , Greg Kroah-Hartman , LKML Subject: Re: [PATCH 4.4 71/96] e1000e: Separate signaling for link check/link up Message-ID: <20171208083441.kvyilu3hhf5pae3q@f1.synalogic.ca> References: <20171128100503.067621614@linuxfoundation.org> <20171128100507.477626859@linuxfoundation.org> <1512676979.18523.193.camel@codethink.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1512676979.18523.193.camel@codethink.co.uk> User-Agent: NeoMutt/20170912 (1.9.0) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4085 Lines: 106 On 2017/12/07 20:02, Ben Hutchings wrote: > On Tue, 2017-11-28 at 11:23 +0100, Greg Kroah-Hartman wrote: > > 4.4-stable review patch.??If anyone has any objections, please let me know. > > > > ------------------ > > > > From: Benjamin Poirier > > > > commit 19110cfbb34d4af0cdfe14cd243f3b09dc95b013 upstream. > [...] > > --- a/drivers/net/ethernet/intel/e1000e/mac.c > > +++ b/drivers/net/ethernet/intel/e1000e/mac.c > > @@ -410,6 +410,9 @@ void e1000e_clear_hw_cntrs_base(struct e > > ? *??Checks to see of the link status of the hardware has changed.??If a > > ? *??change in link status has been detected, then we read the PHY registers > > ? *??to get the current speed/duplex if link exists. > > + * > > + *??Returns a negative error code (-E1000_ERR_*) or 0 (link down) or 1 (link > > + *??up). > > ? **/ > > ?s32 e1000e_check_for_copper_link(struct e1000_hw *hw) > > ?{ > [...] > > --- a/drivers/net/ethernet/intel/e1000e/netdev.c > > +++ b/drivers/net/ethernet/intel/e1000e/netdev.c > > @@ -5017,7 +5017,7 @@ static bool e1000e_has_link(struct e1000 > > > ? case e1000_media_type_copper: > > > ? if (hw->mac.get_link_status) { > > > ? ret_val = hw->mac.ops.check_for_link(hw); > > > - link_active = !hw->mac.get_link_status; > > > + link_active = ret_val > 0; > > > ? } else { > > > ? link_active = true; > > > ? } > > As this change in e1000e_has_link() is conditional only on the media > type, doesn't e1000_check_for_copper_link_ich8lan() also need to be > changed to return 1 for link up? You're right. I looked at it again, in the commit log I wrote that "hw->mac.ops.check_for_link(hw) === e1000e_check_for_copper_link" which is true for the race condition reported (because that's the function in use on adapters that have msix vectors mac.type == e1000_82574) but not generally true. The other check_for_link callback needs to be adjusted likewise. However, I happen to have a I218-LM (e1000_pch_lpt) so I tested 4.14.3 and this error only delays link up, it doesn't prevent it. e1000_check_for_copper_link_ich8lan() sets mac->get_link_status = false; and on the next watchdog execution, we fall in the second branch of the following e1000e_has_link code: case e1000_media_type_copper: if (hw->mac.get_link_status) { ret_val = hw->mac.ops.check_for_link(hw); link_active = ret_val > 0; } else { link_active = true; OTOH, there are multiple reports in https://bugzilla.kernel.org/show_bug.cgi?id=198047 that reverting 830466993daf ("e1000e: Separate signaling for link check/link up") fixes the issue so there's something I'm missing. Gabriel and Christian, can you test the following patch? diff --git a/drivers/net/ethernet/intel/e1000e/ich8lan.c b/drivers/net/ethernet/intel/e1000e/ich8lan.c index d6d4ed7acf03..31277d3bb7dc 100644 --- a/drivers/net/ethernet/intel/e1000e/ich8lan.c +++ b/drivers/net/ethernet/intel/e1000e/ich8lan.c @@ -1367,6 +1367,9 @@ static s32 e1000_disable_ulp_lpt_lp(struct e1000_hw *hw, bool force) * Checks to see of the link status of the hardware has changed. If a * change in link status has been detected, then we read the PHY registers * to get the current speed/duplex if link exists. + * + * Returns a negative error code (-E1000_ERR_*) or 0 (link down) or 1 (link + * up). **/ static s32 e1000_check_for_copper_link_ich8lan(struct e1000_hw *hw) { @@ -1382,7 +1385,7 @@ static s32 e1000_check_for_copper_link_ich8lan(struct e1000_hw *hw) * Change or Rx Sequence Error interrupt. */ if (!mac->get_link_status) - return 0; + return 1; /* First we want to see if the MII Status Register reports * link. If so, then we want to get the current speed/duplex @@ -1613,10 +1616,12 @@ static s32 e1000_check_for_copper_link_ich8lan(struct e1000_hw *hw) * different link partner. */ ret_val = e1000e_config_fc_after_link_up(hw); - if (ret_val) + if (ret_val) { e_dbg("Error configuring flow control\n"); + return ret_val; + } - return ret_val; + return 1; } static s32 e1000_get_variants_ich8lan(struct e1000_adapter *adapter) -- 2.15.1