From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paul Gortmaker <paul.gortmaker@windriver.com>
Subject: Re: [PATCH RT 2/4] net: gianfar: do not try to cleanup TX packets
 if they are not done
Date: Tue, 29 Apr 2014 10:16:51 -0400
Message-ID: <535FB453.2060100@windriver.com>
References: <20140427143119.898655303@goodmis.org> <20140427143140.384915886@goodmis.org> <535DF744.60606@linutronix.de>
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Cc: Thomas Gleixner <tglx@linutronix.de>,
	Carsten Emde <C.Emde@osadl.org>,
	John Kacur <jkacur@redhat.com>, <stable-rt@vger.kernel.org>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Steven Rostedt <rostedt@goodmis.org>,
	<linux-kernel@vger.kernel.org>,
	linux-rt-users <linux-rt-users@vger.kernel.org>
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On 14-04-28 02:37 AM, Sebastian Andrzej Siewior wrote:
> On 04/27/2014 04:31 PM, Steven Rostedt wrote:
>> diff --git a/drivers/net/ethernet/freescale/gianfar.c b/drivers/net/ethernet/freescale/gianfar.c
>> index 5c0efcc..8aecc1d 100644
>> --- a/drivers/net/ethernet/freescale/gianfar.c
>> +++ b/drivers/net/ethernet/freescale/gianfar.c
>> @@ -2856,10 +2855,14 @@ static int gfar_poll(struct napi_struct *napi, int budget)
>>  			tx_queue = priv->tx_queue[i];
>>  			/* run Tx cleanup to completion */
>>  			if (tx_queue->tx_skbuff[tx_queue->skb_dirtytx]) {
>> -				gfar_clean_tx_ring(tx_queue);
>> -				has_tx_work = 1;
>> +				int ret;
>> +
>> +				ret = gfar_clean_tx_ring(tx_queue);
>> +				if (ret)
>> +					has_tx_work++;
>>  			}
>>  		}
>> +		work_done += has_tx_work;
>>  
>>  		for_each_set_bit(i, &gfargrp->rx_bit_map, priv->num_rx_queues) {
>>  			/* skip queue if not active */
> 
> The 3.14-RT version of the patch should have an additional return
> statement here which I forgot initially.

Sanity boot tested the 3.10 rc1 on a sbc8548 (UP PPC with gianfar), with
the one-liner added as follows:

diff --git a/drivers/net/ethernet/freescale/gianfar.c b/drivers/net/ethernet/freescale/gianfar.c
index 8aecc1d81395..b87a8c919c3e 100644
--- a/drivers/net/ethernet/freescale/gianfar.c
+++ b/drivers/net/ethernet/freescale/gianfar.c
@@ -2574,6 +2574,7 @@ static int gfar_clean_tx_ring(struct gfar_priv_tx_q *tx_queue)
        tx_queue->dirty_tx = bdp;
 
        netdev_tx_completed_queue(txq, howmany, bytes_sent);
+       return howmany;
 }
 
 static void gfar_schedule_cleanup(struct gfar_priv_grp *gfargrp)

Paul.
--


> 
> Sebastian
>