From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Kleine-Budde Subject: [PATCH 2/3] can: at91_can: RX queue could get stuck at high bus load Date: Mon, 20 Jun 2016 10:00:29 +0200 Message-ID: <1466409630-6268-3-git-send-email-mkl@pengutronix.de> References: <1466409630-6268-1-git-send-email-mkl@pengutronix.de> Return-path: Received: from metis.ext.4.pengutronix.de ([92.198.50.35]:46465 "EHLO metis.ext.4.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752409AbcFTIAm (ORCPT ); Mon, 20 Jun 2016 04:00:42 -0400 In-Reply-To: <1466409630-6268-1-git-send-email-mkl@pengutronix.de> Sender: linux-can-owner@vger.kernel.org List-ID: To: netdev@vger.kernel.org Cc: davem@davemloft.net, linux-can@vger.kernel.org, kernel@pengutronix.de, Wolfgang Grandegger , stable@vger.kernel.org, Marc Kleine-Budde From: Wolfgang Grandegger 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 Tested-by: Amr Bekhit Cc: Signed-off-by: Marc Kleine-Budde --- drivers/net/can/at91_can.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) 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; -- 2.8.1