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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 <stable@vger.kernel.org>
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Markus Pargmann 2013-10-28 09:54:40 +01:00 committed by Marc Kleine-Budde
parent c17cb8b55b
commit 5d0f801a2c
1 changed files with 3 additions and 3 deletions
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6
drivers/net/can/c_can/c_can.c
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@ -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;