From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1755010AbbKJSID (ORCPT <rfc822;w@1wt.eu>);
	Tue, 10 Nov 2015 13:08:03 -0500
Received: from unicorn.mansr.com ([81.2.72.234]:42603 "EHLO unicorn.mansr.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1751371AbbKJSIB convert rfc822-to-8bit (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Tue, 10 Nov 2015 13:08:01 -0500
From: =?iso-8859-1?Q?M=E5ns_Rullg=E5rd?= <mans@mansr.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, slash.tmp@free.fr
Subject: Re: [PATCH v5] net: ethernet: add driver for Aurora VLSI NB8800 Ethernet controller
References: <1447172063-27234-1-git-send-email-mans@mansr.com>
	<1447178287.17135.77.camel@edumazet-glaptop2.roam.corp.google.com>
Date: Tue, 10 Nov 2015 18:07:59 +0000
In-Reply-To: <1447178287.17135.77.camel@edumazet-glaptop2.roam.corp.google.com>
	(Eric Dumazet's message of "Tue, 10 Nov 2015 09:58:07 -0800")
Message-ID: <yw1xmvulram8.fsf@unicorn.mansr.com>
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux)
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: 8BIT
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Eric Dumazet <eric.dumazet@gmail.com> writes:

> On Tue, 2015-11-10 at 16:14 +0000, Mans Rullgard wrote:
>> This adds a driver for the Aurora VLSI NB8800 Ethernet controller.
>> It is an almost complete rewrite of a driver originally found in
>> a Sigma Designs 2.6.22 tree.
>
> ...
>
>> +
>> +static int nb8800_xmit(struct sk_buff *skb, struct net_device *dev)
>> +{
>> +	struct nb8800_priv *priv = netdev_priv(dev);
>> +	struct nb8800_tx_desc *txd;
>> +	struct nb8800_tx_buf *txb;
>> +	struct nb8800_dma_desc *dma;
>> +	dma_addr_t dma_addr;
>> +	unsigned int dma_len;
>> +	unsigned long flags;
>> +	int align;
>> +	int next;
>> +
>> +	if (atomic_read(&priv->tx_free) <= NB8800_DESC_LOW) {
>> +		netif_stop_queue(dev);
>> +		return NETDEV_TX_BUSY;
>> +	}
>> +
>> +	align = (8 - (uintptr_t)skb->data) & 7;
>> +
>> +	dma_len = skb->len - align;
>> +	dma_addr = dma_map_single(&dev->dev, skb->data + align,
>> +				  dma_len, DMA_TO_DEVICE);
>> +
>> +	if (dma_mapping_error(&dev->dev, dma_addr)) {
>> +		netdev_err(dev, "tx dma mapping error\n");
>> +		kfree_skb(skb);
>> +		dev->stats.tx_dropped++;
>> +		return NETDEV_TX_OK;
>> +	}
>> +
>> +	if (atomic_dec_return(&priv->tx_free) <= NB8800_DESC_LOW)
>> +		netif_stop_queue(dev);
>
> You probably also want to clear skb->xmit_more or risk a stall

Very true, will fix.

-- 
Måns Rullgård
mans@mansr.com