netdev - RE: [PATCH 1/3] bnx2x: remove TPA_ENABLE

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Message-ID: <8628FE4E7912BF47A96AE7DD7BAC0AAD01067097B03C@SJEXCHCCR02.corp.ad.broadcom.com>
Date:	Thu, 1 Sep 2011 01:37:56 -0700
From:	"Vladislav Zolotarov" <vladz@...adcom.com>
To:	Michał Mirosław <mirqus@...il.com>
cc:	"Michal Schmidt" <mschmidt@...hat.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"Dmitry Kravkov" <dmitry@...adcom.com>,
	"Eilon Greenstein" <eilong@...adcom.com>
Subject: RE: [PATCH 1/3] bnx2x: remove TPA_ENABLE_FLAG



> -----Original Message-----
> From: netdev-owner@...r.kernel.org [mailto:netdev-
> owner@...r.kernel.org] On Behalf Of Michal Miroslaw
> Sent: Wednesday, August 31, 2011 9:05 PM
> To: Vladislav Zolotarov
> Cc: Michal Schmidt; netdev@...r.kernel.org; Dmitry Kravkov; Eilon
> Greenstein
> Subject: Re: [PATCH 1/3] bnx2x: remove TPA_ENABLE_FLAG
> 
> 2011/8/31 Vladislav Zolotarov <vladz@...adcom.com>:
> >> -----Original Message-----
> >> From: Michal Schmidt [mailto:mschmidt@...hat.com]
> >> Sent: Wednesday, August 31, 2011 6:59 PM
> >> To: Vladislav Zolotarov
> >> Cc: netdev@...r.kernel.org; Dmitry Kravkov; Eilon Greenstein;
> >> mirqus@...il.com
> >> Subject: Re: [PATCH 1/3] bnx2x: remove TPA_ENABLE_FLAG
> >>
> >> On Wed, 31 Aug 2011 18:16:30 +0300 Vlad Zolotarov wrote:
> >> > On Wednesday 31 August 2011 18:00:34 Michal Schmidt wrote:
> >> > >   if (bnx2x_reload) {
> >> > > -         if (bp->recovery_state == BNX2X_RECOVERY_DONE)
> >> > > +         if (bp->recovery_state == BNX2X_RECOVERY_DONE) {
> >> > > +                 /*
> >> > > +                  * Cheat! Normally dev->features will be
> >> > > set after we
> >> > > +                  * return, but that's too late. We need to
> >> > > know how to
> >> > > +                  * configure the NIC when reloading it, so
> >> > > update
> >> > > +                  * the features early.
> >> > > +                  */
> >> > > +                 dev->features = features;
> >> > >                   return bnx2x_reload_if_running(dev);
> >> >
> >> > NACK
> >> >
> >> > This is bogus - what if bnx2x_reload_if_running(dev)
> >> > (bnx2x_nic_load()) failes? The original dev->features would be
> >> > lost...
> >>
> >> Well, yes, but since the NIC would be now not working, do we really
> >> care about its features? :-)
> >
> > U r kidding, right? ;)
> > We care about the consistency in the netdev features state - if we
> failed
> > to configure the requested feature and returned an error on e.g.
> "ethtool -K ethX lro on"
> > call, it's expected that a subsequent ethtool -k ethX call won't
> report the requested
> > feature (LRO) as set.
> 
> If bnx2x_reload_if_running() failure means that NIC is disabled, then
> Michal is right that there's no point in caring about dev->features,
> sice 'load' operation (NIC configuration) needs to be done again
> anyway.

Michal, it's a matter of a consistent semantics/behavior of the ethtool callbacks just as I described above.
As long as dev->features may be queried both when device is down I'm afraid I can't agree with u.

Thanks,
vlad

> 
> Best Regards,
> Michał Mirosław
> --
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