Re: [PATCH] i40e: don't enable and init FCOE by default when do PF reset

From: ethan zhao
Date: Fri Jan 16 2015 - 22:02:02 EST

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Vasu,

What' your idea about the v2, any suggestion ? Jeff is looking forward to see it.

Thanks,
Ethan

On 2015/1/16 22:47, Jeff Kirsher wrote:

On Fri, 2015-01-16 at 09:48 +0800, ethan zhao wrote:

Vasu,

OK, disable FCOE as default configuration as a temporary step to
make it work.

Sounds like I should expect a v2 coming, correct?

Thanks,
Ethan

On 2015/1/16 7:45, Dev, Vasu wrote:

-----Original Message-----
From: ethan zhao [mailto:ethan.zhao@xxxxxxxxxx]
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@xxxxxxxxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-
kernel@xxxxxxxxxxxxxxx; brian.maly@xxxxxxxxxx
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@xxxxxxxxx>
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@xxxxxxxxxxxxxxx>
Signed-off-by: Vasu Dev <vasu.dev@xxxxxxxxx>
Tested-by: Jim Young <jamesx.m.young@xxxxxxxxx>

---
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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Next message: Ray Jui: "Re: How to handle access to multiple PHYs through MDIO"
Previous message: Randy Dunlap: "Re: mmotm 2015-01-16-15-50 uploaded (netfilter xt_TPROXY.c)"
In reply to: Jeff Kirsher: "Re: [PATCH] i40e: don't enable and init FCOE by default when do PF reset"
Next in thread: Dev, Vasu: "RE: [PATCH] i40e: don't enable and init FCOE by default when do PF reset"
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