From: Markus Pargmann Date: Mon, 28 Oct 2013 08:54:40 +0000 (+0100) Subject: can: c_can: Fix RX message handling, handle lost message before EOB X-Git-Tag: firefly_0821_release~176^2~5062^2~1^2~1 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=5d0f801a2c;p=firefly-linux-kernel-4.4.55.git can: c_can: Fix RX message handling, handle lost message before EOB 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. Cc: linux-stable Signed-off-by: Markus Pargmann Signed-off-by: Marc Kleine-Budde --- diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c index a668cd491cb3..e3fc07cf2f62 100644 --- 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_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++; @@ -824,6 +821,9 @@ 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;