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

From: ethan zhao
Date: Mon Jan 19 2015 - 21:06:11 EST



On 2015/1/20 5:10, Dev, Vasu wrote:
-----Original Message-----
From: ethan zhao [mailto:ethan.zhao@xxxxxxxxxx]
Sent: Friday, January 16, 2015 7:01 PM
To: Kirsher, Jeffrey T
Cc: Dev, Vasu; Ethan Zhao; Ronciak, John; 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,

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

Jeff was asking for v2 in response to your last comment as "disable FCOE as default configuration as a temporary step" but I think that is the fix and user should n't enable FCoE until they have FCoE enabled X710 FCoE with either fabric or VN2VN mode FCoE setup.
As a Linux distro, we don't know users have FCoE capable X710 or not, so we couldn't disable the FCoE configuration
by default in the released kernel except FCoE is officially not supported yet with X710, but if yes, fix those bugs I
mentioned is the only choice.


Thanks,
Ethan



Thanks,
Vasu

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

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/