From: Wolfgang Grandegger <wg@grandegger.com>
Date: Mon, 13 Jun 2016 13:44:19 +0000 (+0200)
Subject: can: at91_can: RX queue could get stuck at high bus load
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=43200a4480cbbe660309621817f54cbb93907108;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

can: at91_can: RX queue could get stuck at high bus load

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>
---

diff --git a/drivers/net/can/at91_can.c b/drivers/net/can/at91_can.c
index 8b3275d7792a..8f5e93cb7975 100644
--- a/drivers/net/can/at91_can.c
+++ b/drivers/net/can/at91_can.c
@@ -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;