From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753394AbdK1MdB (ORCPT ); Tue, 28 Nov 2017 07:33:01 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:57288 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752862AbdK1KWd (ORCPT ); Tue, 28 Nov 2017 05:22:33 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lennart Sorensen , Benjamin Poirier , Aaron Brown , Jeff Kirsher , Amit Pundir Subject: [PATCH 3.18 52/67] e1000e: Separate signaling for link check/link up Date: Tue, 28 Nov 2017 11:19:51 +0100 Message-Id: <20171128100426.701142778@linuxfoundation.org> X-Mailer: git-send-email 2.15.0 In-Reply-To: <20171128100420.274075224@linuxfoundation.org> References: <20171128100420.274075224@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Benjamin Poirier commit 19110cfbb34d4af0cdfe14cd243f3b09dc95b013 upstream. Lennart reported the following race condition: \ e1000_watchdog_task \ e1000e_has_link \ hw->mac.ops.check_for_link() === e1000e_check_for_copper_link /* link is up */ mac->get_link_status = false; /* interrupt */ \ e1000_msix_other hw->mac.get_link_status = true; link_active = !hw->mac.get_link_status /* link_active is false, wrongly */ This problem arises because the single flag get_link_status is used to signal two different states: link status needs checking and link status is down. Avoid the problem by using the return value of .check_for_link to signal the link status to e1000e_has_link(). Reported-by: Lennart Sorensen Signed-off-by: Benjamin Poirier Tested-by: Aaron Brown Signed-off-by: Jeff Kirsher Signed-off-by: Amit Pundir Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/intel/e1000e/mac.c | 11 ++++++++--- drivers/net/ethernet/intel/e1000e/netdev.c | 2 +- 2 files changed, 9 insertions(+), 4 deletions(-) --- 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) { @@ -423,7 +426,7 @@ s32 e1000e_check_for_copper_link(struct * 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 @@ -461,10 +464,12 @@ s32 e1000e_check_for_copper_link(struct * 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; } /** --- a/drivers/net/ethernet/intel/e1000e/netdev.c +++ b/drivers/net/ethernet/intel/e1000e/netdev.c @@ -4844,7 +4844,7 @@ 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; }