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From: Jeff Garzik <jgarzik@pobox.com>
To: Stephen Hemminger <shemminger@linux-foundation.org>
Cc: David Miller <davem@davemloft.net>,
	netdev@vger.kernel.org, hadi@cyberus.ca, rusty@rustcorp.com.au
Subject: Re: [PATCH RFC]: napi_struct V4
Date: Wed, 25 Jul 2007 21:55:08 -0400	[thread overview]
Message-ID: <46A7FEFC.4040005@pobox.com> (raw)
In-Reply-To: <20070725095654.38a10abc@oldman.hamilton.local>

Stephen Hemminger wrote:
> The usage of NAPI on 8139cp and 8139too seems dodgy;
> these drivers expect this to work:
> 
> 		local_irq_save(flags);
> 		cpw16_f(IntrMask, cp_intr_mask);
> 		__netif_rx_complete(dev);
> 		local_irq_restore(flags);
> 
> It works on SMP only because if poll races with IRQ, 
> the IRQ is not masked or cleared so the IRQ will get restarted.

Expect?  This _does_ work on both UP and SMP.


> Better would be to change it to:
> 		spin_lock_irqsave(&cp->lock, flags);
> 		cpw16_f(IntrMask, cp_intr_mask);
> 		__netif_rx_complete(dev);
> 		spin_unlock_irqrestore(&cp->lock, flags);
> 
> Which actually is same code on UP.

I'm missing your point?

You claim local_irq_save() works only on SMP, then suggest a solution 
that you agree produces the same result?

I don't see any logic to your request, only added overhead for no reason.

	Jeff



  parent reply	other threads:[~2007-07-26  1:55 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-07-25  8:31 [PATCH RFC]: napi_struct V4 David Miller
2007-07-25  8:56 ` Stephen Hemminger
2007-07-26  0:37   ` David Miller
2007-07-26  1:55   ` Jeff Garzik [this message]
2007-07-26  1:56     ` David Miller
2007-07-26  2:00       ` Jeff Garzik
2007-07-26  2:02         ` David Miller
2007-07-28 18:08           ` Jeff Garzik
2007-07-29  5:33             ` David Miller
2007-07-25 12:01 ` jamal
2007-07-26  4:09 ` David Miller
2007-07-26  6:33   ` Michael Chan
2007-07-26  6:38     ` David Miller
2007-07-26  7:05       ` Michael Chan
2007-07-26  7:15         ` David Miller
2007-07-26 21:38           ` Michael Chan
2007-07-31  0:25             ` David Miller
2007-07-26  6:39   ` Michael Chan
2007-07-26  6:43     ` David Miller
2007-07-28 15:27 ` Roland Dreier
2007-07-29  5:32   ` David Miller
2007-07-30 15:04     ` Roland Dreier
2007-07-30 22:48       ` David Miller
2007-07-31  2:01         ` Roland Dreier
2007-07-31  2:03           ` David Miller

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