Date:	Thu, 15 Jan 2015 23:45:01 +0000
From:	"Dev, Vasu" <vasu.dev@...el.com>
To:	ethan zhao <ethan.zhao@...cle.com>
CC:	Ethan Zhao <ethan.kernel@...il.com>,
	"Ronciak, John" <john.ronciak@...el.com>,
	"Kirsher, Jeffrey T" <jeffrey.t.kirsher@...el.com>,
	"Brandeburg, Jesse" <jesse.brandeburg@...el.com>,
	"Allan, Bruce W" <bruce.w.allan@...el.com>,
	"Wyborny, Carolyn" <carolyn.wyborny@...el.com>,
	"Skidmore, Donald C" <donald.c.skidmore@...el.com>,
	"Rose, Gregory V" <gregory.v.rose@...el.com>,
	"Vick, Matthew" <matthew.vick@...el.com>,
	"Williams, Mitch A" <mitch.a.williams@...el.com>,
	"Parikh, Neerav" <neerav.parikh@...el.com>,
	Linux NICS <Linux-nics@...tope.jf.intel.com>,
	"e1000-devel@...ts.sourceforge.net" 
	<e1000-devel@...ts.sourceforge.net>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"brian.maly@...cle.com" <brian.maly@...cle.com>
Subject: RE: [PATCH] i40e: don't enable and init FCOE by default when do PF
 reset

> -----Original Message-----
> From: ethan zhao [mailto:ethan.zhao@...cle.com]
> Sent: Tuesday, January 13, 2015 6:41 PM
> To: Dev, Vasu
> Cc: Ethan Zhao; Ronciak, John; Kirsher, Jeffrey T; Brandeburg, Jesse; Allan,
> Bruce W; Wyborny, Carolyn; Skidmore, Donald C; Rose, Gregory V; Vick,
> Matthew; Williams, Mitch A; Parikh, Neerav; Linux NICS; e1000-
> devel@...ts.sourceforge.net; netdev@...r.kernel.org; linux-
> kernel@...r.kernel.org; brian.maly@...cle.com
> Subject: Re: [PATCH] i40e: don't enable and init FCOE by default when do PF
> reset
> 
> Vasu,
> 
> On 2015/1/14 3:38, Dev, Vasu wrote:
> >> -----Original Message-----
> >>>>> diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c
> >>>>> b/drivers/net/ethernet/intel/i40e/i40e_main.c
> >>>>> index a5f2660..a2572cc 100644
> >>>>> --- a/drivers/net/ethernet/intel/i40e/i40e_main.c
> >>>>> +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
> >>>>> @@ -6180,9 +6180,12 @@ static void i40e_reset_and_rebuild(struct
> >>>>> i40e_pf *pf, bool reinit)
> >>>>>      }
> >>>>>   #endif /* CONFIG_I40E_DCB */
> >>>>>   #ifdef I40E_FCOE
> >>>>> -   ret = i40e_init_pf_fcoe(pf);
> >>>>> -   if (ret)
> >>>>> -           dev_info(&pf->pdev->dev, "init_pf_fcoe failed: %d\n", ret);
> >>>>> +   if (pf->flags & I40E_FLAG_FCOE_ENABLED) {
> >>>>> +           ret = i40e_init_pf_fcoe(pf);
> >>> Calling i40e_init_pf_fcoe() here conflicts with its
> >> I40E_FLAG_FCOE_ENABLED pre-condition since
> I40E_FLAG_FCOE_ENABLED is
> >> set by very same i40e_init_pf_fcoe(), in turn i40e_init_pf_fcoe()
> >> will never get called.
> >>
> >> I don't think so,  here ,i40e_reset_and_rebuild()  is not the only
> >> and the first place that  i40e_init_pf_fcoe() is called, see
> >> i40e_probe(), that is the first chance.
> >>
> >> i40e_probe()
> >> -->i40e_sw_init()
> >>       -->i40e_init_pf_fcoe()
> >>
> >> And the I40E_FLAG_FCOE_ENABLED is possible be set by
> >> i40e_fcoe_enable() or i40e_fcoe_disable() interface before the reset
> >> action is to be done.
> >>
> > It is set by i40e_init_pf_fcoe() and you are right that the modified call flow
> by your patch won't impact setting of I40E_FLAG_FCOE_ENABLED anyway
> which could have prevented calling i40e_init_pf_fcoe() as I described above,
> so this is not an issue with the patch.
> >
> >> BTW, the reason I post this patch is that we hit a bug, after setup
> >> vlan, the PF is enabled to FCOE.
> >>
> > Then that BUG would still remain un-fixed and calling i40e_init_pf_fcoe()
> under I40E_FLAG_FCOE_ENABLED  flag really won't affect call flow to fix
> anything. I mean I40E_FLAG_FCOE_ENABLED  condition will be true with "pf-
> >hw.func_caps.fcoe == true" and otherwise calling i40e_init_pf_fcoe() simply
> returns back early on after checking "pf->hw.func_caps.fcoe == false", so
> how that bug is fixed here by added I40E_FLAG_FCOE_ENABLED  condition ?
> What is the bug ?
>   The func_caps.fcoe is assigned by following call path, under our test
> environment,
> 
>   i40e_probe()
>    ->i40e_get_capabilities()
>       ->i40e_aq_discover_capabilities()
>          ->i40e_parse_discover_capabilities()
> 
>   Or
> 
>   i40e_reset_and_rebuild()
>    ->i40e_get_capabilities()
>      ->i40e_aq_discover_capabilities()
>        ->i40e_parse_discover_capabilities()
> 
>   Under our test environment, the "pf->hw.func_caps.fcoe" is true. so if
> i40e_reset_and_rebuild() is called for VLAN setup, ethtool diagnostic test.
>   And then i40e_init_pf_fcoe() is to be called,
> 
>   While if (!pf->hw.func_caps.fcoe) wouldn't return,
> 

I said it would return with "pf->hw.func_caps.fcoe == false" in my last response, more details below.

>   So  pf->flags is set to I40E_FLAG_FCOE_ENABLED.
> 
>   With my patch,  i40e_init_pf_fcoe() is only called after
> I40E_FLAG_FCOE_ENABLED is set before reset.
> 
> Enable FCOE in i40e_probe() or not is another issue.
> 

Nope since both cases we should do i40e_init_pf_fcoe() or don't based on fcoe cap true or false. 

I don't have much to add as I described before with the your patch that "calling i40e_init_pf_fcoe() under I40E_FLAG_FCOE_ENABLED  flag really won't affect call flow to fix anything. I mean I40E_FLAG_FCOE_ENABLED  condition will be true with "pf->hw.func_caps.fcoe == true" and otherwise calling i40e_init_pf_fcoe() simply returns back early on after checking "pf->hw.func_caps.fcoe == false". 

May be I'm missing something, I guess next either go with CONFIG_I40E_FCOE disable as I suggested before and now it in upstream kernel or we can have further off list discussion to fix the issue you are trying to fix with the patch.

Thanks,
Vasu

> Thanks,
> Ethan
> 
> 
> >
> >>> Jeff Kirsher should be getting out a patch queued by me which adds
> >> I40E_FCoE Kbuild option, in that FCoE is disabled by default and
> >> user could enable FCoE only if needed, that patch would do same of
> >> skipping
> >> i40e_init_pf_fcoe() whether FCoE capability in device enabled or not
> >> in default config.
> >> The following patch will not fix the above issue -- configuration of
> >> PF will be changed via reset.
> >> How about the FCOE is configured and disabled by  i40e_fcoe_disable()
> >> , then reset happens ?
> >>
> > May be but if the BUG is due to FCoE being enabled then having it disabled
> in config will avoid the bug for non FCoE config option and once bug is
> understood then that has to be fixed for FCoE enabled config also as I asked
> above.
> >
> > Thanks Ethan for detailed response.
> > Vasu
> >
> >>>  From patchwork Wed Oct  2 23:26:08 2013
> >>> Content-Type: text/plain; charset="utf-8"
> >>> MIME-Version: 1.0
> >>> Content-Transfer-Encoding: 7bit
> >>> Subject: [net] i40e: adds FCoE configure option
> >>> Date: Thu, 03 Oct 2013 07:26:08 -0000
> >>> From: Vasu Dev <vasu.dev@...el.com>
> >>> X-Patchwork-Id: 11797
> >>>
> >>> Adds FCoE config option I40E_FCOE, so that FCoE can be enabled as
> >>> needed but otherwise have it disabled by default.
> >>>
> >>> This also eliminate multiple FCoE config checks, instead now just
> >>> one config check for CONFIG_I40E_FCOE.
> >>>
> >>> The I40E FCoE was added with 3.17 kernel and therefore this patch
> >>> shall be applied to stable 3.17 kernel also.
> >>>
> >>> CC: <stable@...r.kernel.org>
> >>> Signed-off-by: Vasu Dev <vasu.dev@...el.com>
> >>> Tested-by: Jim Young <jamesx.m.young@...el.com>
> >>>
> >>> ---
> >>> drivers/net/ethernet/intel/Kconfig           |   11 +++++++++++
> >>>   drivers/net/ethernet/intel/i40e/Makefile     |    2 +-
> >>>   drivers/net/ethernet/intel/i40e/i40e_osdep.h |    4 ++--
> >>>   3 files changed, 14 insertions(+), 3 deletions(-)
> >>>
> >>> diff --git a/drivers/net/ethernet/intel/Kconfig
> >>> b/drivers/net/ethernet/intel/Kconfig
> >>> index 5b8300a..4d61ef5 100644
> >>> --- a/drivers/net/ethernet/intel/Kconfig
> >>> +++ b/drivers/net/ethernet/intel/Kconfig
> >>> @@ -281,6 +281,17 @@ config I40E_DCB
> >>>
> >>>            If unsure, say N.
> >>>
> >>> +config I40E_FCOE
> >>> +       bool "Fibre Channel over Ethernet (FCoE)"
> >>> +       default n
> >>> +       depends on I40E && DCB && FCOE
> >>> +       ---help---
> >>> +         Say Y here if you want to use Fibre Channel over Ethernet (FCoE)
> >>> +         in the driver. This will create new netdev for exclusive FCoE
> >>> +         use with XL710 FCoE offloads enabled.
> >>> +
> >>> +         If unsure, say N.
> >>> +
> >>>   config I40EVF
> >>>          tristate "Intel(R) XL710 X710 Virtual Function Ethernet support"
> >>>          depends on PCI_MSI
> >>> diff --git a/drivers/net/ethernet/intel/i40e/Makefile
> >>> b/drivers/net/ethernet/intel/i40e/Makefile
> >>> index 4b94ddb..c405819 100644
> >>> --- a/drivers/net/ethernet/intel/i40e/Makefile
> >>> +++ b/drivers/net/ethernet/intel/i40e/Makefile
> >>> @@ -44,4 +44,4 @@ i40e-objs := i40e_main.o \
> >>>          i40e_virtchnl_pf.o
> >>>
> >>>   i40e-$(CONFIG_I40E_DCB) += i40e_dcb.o i40e_dcb_nl.o
> >>> -i40e-$(CONFIG_FCOE:m=y) += i40e_fcoe.o
> >>> +i40e-$(CONFIG_I40E_FCOE) += i40e_fcoe.o
> >>> diff --git a/drivers/net/ethernet/intel/i40e/i40e_osdep.h
> >>> b/drivers/net/ethernet/intel/i40e/i40e_osdep.h
> >>> index 045b5c4..ad802dd 100644
> >>> --- a/drivers/net/ethernet/intel/i40e/i40e_osdep.h
> >>> +++ b/drivers/net/ethernet/intel/i40e/i40e_osdep.h
> >>> @@ -78,7 +78,7 @@ do {                                                            \
> >>>   } while (0)
> >>>
> >>>   typedef enum i40e_status_code i40e_status; -#if
> >>> defined(CONFIG_FCOE)
> >>> || defined(CONFIG_FCOE_MODULE)
> >>> +#ifdef CONFIG_I40E_FCOE
> >>>   #define I40E_FCOE
> >>> -#endif /* CONFIG_FCOE or CONFIG_FCOE_MODULE */
> >>> +#endif
> >>>   #endif /* _I40E_OSDEP_H_ */
> >>>
> >>>>> +           if (ret)
> >>>>> +                   dev_info(&pf->pdev->dev,
> >>>>> +                            "init_pf_fcoe failed: %d\n", ret);
> >>>>> +   }
> >>>>>
> >>>>>   #endif
> >>>>>      /* do basic switch setup */
> >>>>> --
> >>>>> 1.8.3.1
> >> Thanks,
> >> Ethan

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