This is a note to let you know that I've just added the patch titled

    can: c_can: Fix RX message handling, handle lost message before EOB

to the 3.12-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     can-c_can-fix-rx-message-handling-handle-lost-message-before-eob.patch
and it can be found in the queue-3.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 5d0f801a2ccec3b1fdabc3392c8d99ed0413d216 Mon Sep 17 00:00:00 2001
From: Markus Pargmann <m...@pengutronix.de>
Date: Mon, 28 Oct 2013 09:54:40 +0100
Subject: can: c_can: Fix RX message handling, handle lost message before EOB

From: Markus Pargmann <m...@pengutronix.de>

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 <m...@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <m...@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/net/can/c_can/c_can.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/net/can/c_can/c_can.c
+++ b/drivers/net/can/c_can/c_can.c
@@ -814,9 +814,6 @@ static int c_can_do_rx_poll(struct net_d
                        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++;
@@ -824,6 +821,9 @@ static int c_can_do_rx_poll(struct net_d
                                continue;
                        }
 
+                       if (msg_ctrl_save & IF_MCONT_EOB)
+                               return num_rx_pkts;
+
                        if (!(msg_ctrl_save & IF_MCONT_NEWDAT))
                                continue;
 


Patches currently in stable-queue which might be from m...@pengutronix.de are

queue-3.12/can-c_can-fix-rx-message-handling-handle-lost-message-before-eob.patch
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