From patchwork Thu Dec 14 15:17:43 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joseph Salisbury X-Patchwork-Id: 848611 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=lists.ubuntu.com (client-ip=91.189.94.19; helo=huckleberry.canonical.com; envelope-from=kernel-team-bounces@lists.ubuntu.com; receiver=) Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 3yyHHk4pCwz9t4B; Fri, 15 Dec 2017 02:17:54 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.86_2) (envelope-from ) id 1ePVGg-0002I2-Nf; Thu, 14 Dec 2017 15:17:50 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:128) (Exim 4.86_2) (envelope-from ) id 1ePVGb-0002DE-HY for kernel-team@lists.ubuntu.com; Thu, 14 Dec 2017 15:17:45 +0000 Received: from 1.general.jsalisbury.us.vpn ([10.172.67.212] helo=salisbury) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1ePVGb-00040s-6v for kernel-team@lists.ubuntu.com; Thu, 14 Dec 2017 15:17:45 +0000 Received: by salisbury (Postfix, from userid 1000) id 3834D7E26CB; Thu, 14 Dec 2017 10:17:44 -0500 (EST) From: Joseph Salisbury To: kernel-team@lists.ubuntu.com Subject: [SRU][X, Z, A][PATCH 1/2] e1000e: Separate signaling for link check/link up Date: Thu, 14 Dec 2017 10:17:43 -0500 Message-Id: <657981560c26442b5947562af26e9eacba47fe16.1510153524.git.joseph.salisbury@canonical.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: References: In-Reply-To: References: X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.20 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: "kernel-team" From: Benjamin Poirier BugLink: http://bugs.launchpad.net/bugs/1730550 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 (cherry picked from commit 19110cfbb34d4af0cdfe14cd243f3b09dc95b013) Signed-off-by: Joseph Salisbury --- drivers/net/ethernet/intel/e1000e/mac.c | 11 ++++++++--- drivers/net/ethernet/intel/e1000e/netdev.c | 2 +- 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/intel/e1000e/mac.c b/drivers/net/ethernet/intel/e1000e/mac.c index e59d7c2..645ace7 100644 --- 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 e1000_hw *hw) * 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 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 @@ -461,10 +464,12 @@ s32 e1000e_check_for_copper_link(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; } /** diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c index 9b4ec13..acc0e57 100644 --- a/drivers/net/ethernet/intel/e1000e/netdev.c +++ b/drivers/net/ethernet/intel/e1000e/netdev.c @@ -5006,7 +5006,7 @@ static bool e1000e_has_link(struct e1000_adapter *adapter) 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; }