From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760241Ab3LFXr5 (ORCPT ); Fri, 6 Dec 2013 18:47:57 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:48425 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161371Ab3LFXMi (ORCPT ); Fri, 6 Dec 2013 18:12:38 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Markus Pargmann , Marc Kleine-Budde , Kamal Mostafa Subject: [PATCH 3.8 038/152] can: c_can: Fix RX message handling, handle lost message before EOB Date: Fri, 6 Dec 2013 15:09:22 -0800 Message-Id: <1386371476-2477-39-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1386371476-2477-1-git-send-email-kamal@canonical.com> References: <1386371476-2477-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.8.13.14 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Markus Pargmann commit 5d0f801a2ccec3b1fdabc3392c8d99ed0413d216 upstream. If we handle end of block messages with higher priority than a lost message, we can run into an endless interrupt loop. This is reproducable with a am335x processor and "cansequence -r" at 1Mbit. As soon as we loose a packet we can't escape from an interrupt loop. This patch fixes the problem by handling lost packets before EOB packets. Signed-off-by: Markus Pargmann Signed-off-by: Marc Kleine-Budde Signed-off-by: Kamal Mostafa --- drivers/net/can/c_can/c_can.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c index 2282b1a..915847d 100644 --- a/drivers/net/can/c_can/c_can.c +++ b/drivers/net/can/c_can/c_can.c @@ -810,9 +810,6 @@ static int c_can_do_rx_poll(struct net_device *dev, int quota) msg_ctrl_save = priv->read_reg(priv, C_CAN_IFACE(MSGCTRL_REG, 0)); - if (msg_ctrl_save & IF_MCONT_EOB) - return num_rx_pkts; - if (msg_ctrl_save & IF_MCONT_MSGLST) { c_can_handle_lost_msg_obj(dev, 0, msg_obj); num_rx_pkts++; @@ -820,6 +817,9 @@ static int c_can_do_rx_poll(struct net_device *dev, int quota) continue; } + if (msg_ctrl_save & IF_MCONT_EOB) + return num_rx_pkts; + if (!(msg_ctrl_save & IF_MCONT_NEWDAT)) continue; -- 1.8.3.2