From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: netif_tx_disable and lockless TX
Date: Tue, 30 May 2006 22:11:17 -0700 (PDT)
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From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Wed, 31 May 2006 14:58:11 +1000

> Hi Michael:
> 
> On Tue, May 30, 2006 at 09:51:03PM -0700, Michael Chan wrote:
> >
> > > That's why I suggest that every NIC that uses this feature be forced
> > > to do what TG3 does so only BH disabling is needed.  Once that's done
> > > they can just use xmit_lock and everyone will be happy again.
> > 
> > As long as the tx completion is all done in NAPI, it can use BH
> > disabling
> > without irq disabling.
> 
> Yes, TG3 does not disable IRQs when taking its TX lock.  So do you see
> any problems with replacing the TG3 TX lock using xmit_lock?

I don't see any.

Thanks for reminding me about the IRQ vs. BH disabling issue.

It will come back when net channels arrive :-) This is because net
channel drivers will do all the work in hard IRQs and not in a NAPI or
NAPI-like context.

The only regret I have about that is we will go back to not being able
to profile ->hard_start_xmit() very well in such drivers.