can: at91_can: RX queue could get stuck at high bus load
authorWolfgang Grandegger <wg@grandegger.com>
Mon, 13 Jun 2016 13:44:19 +0000 (15:44 +0200)
committerMarc Kleine-Budde <mkl@pengutronix.de>
Mon, 20 Jun 2016 07:32:40 +0000 (09:32 +0200)
At high bus load it could happen that "at91_poll()" enters with all RX
message boxes filled up. If then at the end the "quota" is exceeded as
well, "rx_next" will not be reset to the first RX mailbox and hence the
interrupts remain disabled.

Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Tested-by: Amr Bekhit <amrbekhit@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
drivers/net/can/at91_can.c

index 8b3275d..8f5e93c 100644 (file)
@@ -712,9 +712,10 @@ static int at91_poll_rx(struct net_device *dev, int quota)
 
        /* upper group completed, look again in lower */
        if (priv->rx_next > get_mb_rx_low_last(priv) &&
-           quota > 0 && mb > get_mb_rx_last(priv)) {
+           mb > get_mb_rx_last(priv)) {
                priv->rx_next = get_mb_rx_first(priv);
-               goto again;
+               if (quota > 0)
+                       goto again;
        }
 
        return received;