Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752475AbcKYJN6 (ORCPT ); Fri, 25 Nov 2016 04:13:58 -0500 Received: from eusmtp01.atmel.com ([212.144.249.243]:34589 "EHLO eusmtp01.atmel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754464AbcKYJMK (ORCPT ); Fri, 25 Nov 2016 04:12:10 -0500 Subject: Re: [PATCH 1/1] net: macb: fix the RX queue reset in macb_rx() To: Cyrille Pitchen , , , References: CC: , , From: Nicolas Ferre Organization: atmel Message-ID: <8c91d53a-3556-4305-ce9d-589753445e19@atmel.com> Date: Fri, 25 Nov 2016 10:11:20 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 8bit X-Originating-IP: [10.145.133.18] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2075 Lines: 57 Le 25/11/2016 ? 09:49, Cyrille Pitchen a ?crit : > On macb only (not gem), when a RX queue corruption was detected from > macb_rx(), the RX queue was reset: during this process the RX ring > buffer descriptor was initialized by macb_init_rx_ring() but we forgot > to also set bp->rx_tail to 0. > > Indeed, when processing the received frames, bp->rx_tail provides the > macb driver with the index in the RX ring buffer of the next buffer to > process. So when the whole ring buffer is reset we must also reset > bp->rx_tail so the driver is synchronized again with the hardware. > > Since macb_init_rx_ring() is called from many locations, currently from > macb_rx() and macb_init_rings(), we'd rather add the "bp->rx_tail = 0;" > line inside macb_init_rx_ring() than add the very same line after each > call of this function. > > Without this fix, the rx queue is not reset properly to recover from > queue corruption and connection drop may occur. > > Signed-off-by: Cyrille Pitchen > Fixes: 9ba723b081a2 ("net: macb: remove BUG_ON() and reset the queue to handle RX errors") Acked-by: Nicolas Ferre Thanks. Regards, > --- > drivers/net/ethernet/cadence/macb.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c > index 0e489bb82456..8ee303b8da08 100644 > --- a/drivers/net/ethernet/cadence/macb.c > +++ b/drivers/net/ethernet/cadence/macb.c > @@ -991,6 +991,7 @@ static inline void macb_init_rx_ring(struct macb *bp) > addr += bp->rx_buffer_size; > } > bp->rx_ring[bp->rx_ring_size - 1].addr |= MACB_BIT(RX_WRAP); > + bp->rx_tail = 0; > } > > static int macb_rx(struct macb *bp, int budget) > @@ -1736,8 +1737,6 @@ static void macb_init_rings(struct macb *bp) > bp->queues[0].tx_head = 0; > bp->queues[0].tx_tail = 0; > bp->queues[0].tx_ring[bp->tx_ring_size - 1].ctrl |= MACB_BIT(TX_WRAP); > - > - bp->rx_tail = 0; > } > > static void macb_reset_hw(struct macb *bp) > -- Nicolas Ferre