From: David Miller <davem@davemloft.net>
To: shemminger@vyatta.com
Cc: mikem@ring3k.org, netdev@vger.kernel.org
Subject: Re: [PATCH] sky2: Avoid race in sky2_change_mtu
Date: Mon, 03 May 2010 16:36:12 -0700 (PDT) [thread overview]
Message-ID: <20100503.163612.37225591.davem@davemloft.net> (raw)
In-Reply-To: <20100503162634.1f004023@nehalam>
From: Stephen Hemminger <shemminger@vyatta.com>
Date: Mon, 3 May 2010 16:26:34 -0700
> On Mon, 03 May 2010 23:18:56 +0900
> Mike McCormack <mikem@ring3k.org> wrote:
>
>> netif_stop_queue does not ensure all in-progress transmits are complete,
>> so use netif_tx_disable() instead.
>>
>> Make sure NAPI polls are disabled, otherwise NAPI might trigger a TX
>> restart between when we stop the queue and NAPI is disabled.
>
> How could NAPI trigger a TX restart? Restart is a timer, not controlled
> by NAPI. There is a different race that your patch isn't covering.
I think he meant to say that NAPI can trigger a TX queue wake, which
indeed it can, and it will if there is space in the TX queue and
we happen to see the TXIDLE status at this time.
prev parent reply other threads:[~2010-05-03 23:36 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-03 14:18 [PATCH] sky2: Avoid race in sky2_change_mtu Mike McCormack
2010-05-03 22:37 ` David Miller
2010-05-03 23:26 ` Stephen Hemminger
2010-05-03 23:36 ` David Miller [this message]
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