From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfgang Grandegger Subject: [PATCH] at91_can: RX queue could get stuck at high bus load Date: Mon, 13 Jun 2016 15:44:19 +0200 Message-ID: <575EB8B3.6050502@grandegger.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mailproxy03.manitu.net ([217.11.48.151]:49488 "EHLO mailproxy03.manitu.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423299AbcFMNoZ (ORCPT ); Mon, 13 Jun 2016 09:44:25 -0400 Sender: linux-can-owner@vger.kernel.org List-ID: To: linux-can@vger.kernel.org Cc: Marc Kleine-Budde , Amr Bekhit 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 --- 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 8b3275d..8f5e93c 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; -- 1.9.1