[PATCH] [SCSI] bnx2fc: fix build error when !CONFIG_MODULES

[PATCH] [SCSI] bnx2fc: fix build error when !CONFIG_MODULES

[Mariusz Kozlowski]

drivers/scsi/bnx2fc/bnx2fc_fcoe.c:1815: error: dereferencing pointer to incomplete type
drivers/scsi/bnx2fc/bnx2fc_fcoe.c:1815: error: ‘MODULE_STATE_LIVE’ undeclared (first use in this function)

Signed-off-by: Mariusz Kozlowski <mk@lab.zgora.pl>
---
 drivers/scsi/bnx2fc/bnx2fc_fcoe.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
index e476e87..689db39 100644
--- a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
+++ b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
@@ -1812,10 +1812,12 @@ static int bnx2fc_disable(struct net_device *netdev)
 
 	mutex_lock(&bnx2fc_dev_lock);
 
+#ifdef CONFIG_SCSI_BNX2X_FCOE_MODULE
 	if (THIS_MODULE->state != MODULE_STATE_LIVE) {
 		rc = -ENODEV;
 		goto nodev;
 	}
+#endif
 
 	/* obtain physical netdev */
 	if (netdev->priv_flags & IFF_802_1Q_VLAN)
@@ -1875,10 +1877,12 @@ static int bnx2fc_enable(struct net_device *netdev)
 	BNX2FC_MISC_DBG("Entered %s\n", __func__);
 	mutex_lock(&bnx2fc_dev_lock);
 
+#ifdef CONFIG_SCSI_BNX2X_FCOE_MODULE
 	if (THIS_MODULE->state != MODULE_STATE_LIVE) {
 		rc = -ENODEV;
 		goto nodev;
 	}
+#endif
 
 	/* obtain physical netdev */
 	if (netdev->priv_flags & IFF_802_1Q_VLAN)
-- 
1.7.0.4

Re: [PATCH] [SCSI] bnx2fc: fix build error when !CONFIG_MODULES

[Mariusz Kozlowski]

On Wed, Mar 02, 2011 at 11:10:03PM +0100, Mariusz Kozlowski wrote:
> drivers/scsi/bnx2fc/bnx2fc_fcoe.c:1815: error: dereferencing pointer to incomplete type
> drivers/scsi/bnx2fc/bnx2fc_fcoe.c:1815: error: ‘MODULE_STATE_LIVE’ undeclared (first use in this function)

Hm. Still there in next-20110307. Is this patch wrong or..?

-- 
Mariusz Kozlowski

Re: [PATCH] [SCSI] bnx2fc: fix build error when !CONFIG_MODULES

[Bhanu Gollapudi]

On Mon, 2011-03-07 at 12:16 -0800, Mariusz Kozlowski wrote: 
> On Wed, Mar 02, 2011 at 11:10:03PM +0100, Mariusz Kozlowski wrote:
> > drivers/scsi/bnx2fc/bnx2fc_fcoe.c:1815: error: dereferencing pointer to incomplete type
> > drivers/scsi/bnx2fc/bnx2fc_fcoe.c:1815: error: ‘MODULE_STATE_LIVE’ undeclared (first use in this function)
> 
> Hm. Still there in next-20110307. Is this patch wrong or..?
> 

James,

Here is my ack for this patch.

Thanks,
Bhanu

Re: [PATCH] [SCSI] bnx2fc: fix build error when !CONFIG_MODULES

[James Bottomley]

On Mon, 2011-03-07 at 15:54 -0800, Bhanu Gollapudi wrote:
> On Mon, 2011-03-07 at 12:16 -0800, Mariusz Kozlowski wrote: 
> > On Wed, Mar 02, 2011 at 11:10:03PM +0100, Mariusz Kozlowski wrote:
> > > drivers/scsi/bnx2fc/bnx2fc_fcoe.c:1815: error: dereferencing pointer to incomplete type
> > > drivers/scsi/bnx2fc/bnx2fc_fcoe.c:1815: error: ‘MODULE_STATE_LIVE’ undeclared (first use in this function)
> > 
> > Hm. Still there in next-20110307. Is this patch wrong or..?
> > 
> 
> James,
> 
> Here is my ack for this patch.

OK, so the patch is actually wrong because adding #ifdefs on modules in
files really impedes readability.  The bug is using a direct deref on
module state instead of one of the APIs which work in the non-modular
case, namely try_module_get(). That means the other two need to come out
and be reworked (plus all the others in fcoe).

Reworked looks like it might be a bigger item than bnx2fc.  If any of
those tests is ever relevant, it means we have a race in the
fcoe_transport because it shouldn't be calling function pointers on a
dying module (unless it wants to trigger an oops).

So, why are you trying to do this in the first place?

James

Re: [PATCH] [SCSI] bnx2fc: fix build error when !CONFIG_MODULES

[Robert Love]

On Mon, 2011-03-07 at 16:18 -0800, James Bottomley wrote:
> On Mon, 2011-03-07 at 15:54 -0800, Bhanu Gollapudi wrote:
> > On Mon, 2011-03-07 at 12:16 -0800, Mariusz Kozlowski wrote: 
> > > On Wed, Mar 02, 2011 at 11:10:03PM +0100, Mariusz Kozlowski wrote:
> > > > drivers/scsi/bnx2fc/bnx2fc_fcoe.c:1815: error: dereferencing pointer to incomplete type
> > > > drivers/scsi/bnx2fc/bnx2fc_fcoe.c:1815: error: ‘MODULE_STATE_LIVE’ undeclared (first use in this function)
> > > 
> > > Hm. Still there in next-20110307. Is this patch wrong or..?
> > > 
> > 
> > James,
> > 
> > Here is my ack for this patch.
> 
> OK, so the patch is actually wrong because adding #ifdefs on modules in
> files really impedes readability.  The bug is using a direct deref on
> module state instead of one of the APIs which work in the non-modular
> case, namely try_module_get(). That means the other two need to come out
> and be reworked (plus all the others in fcoe).
> 
> Reworked looks like it might be a bigger item than bnx2fc.  If any of
> those tests is ever relevant, it means we have a race in the
> fcoe_transport because it shouldn't be calling function pointers on a
> dying module (unless it wants to trigger an oops).
> 
> So, why are you trying to do this in the first place?
> 
First, fcoe.c started with these checks. Here is a comment in fcoe.c at
the point of one of the checks.

/*
 * Make sure the module has been initialized, and is not about to be
 * removed.  Module paramter sysfs files are writable before the
 * module_init function is called and after module_exit.
 */

I don't know the correct way to fix that race is, but we may be past the
need to fix it in the LLDs.

Next, the fcoe transport was added. Since it (libfcoe.ko) is now calling
what used to be the fcoe.ko sysfs entry points I don't think the problem
exists in fcoe.c or in bnx2fc_fcoe.c, the problem should be in the fcoe
transport code, as James suggested.

The fcoe transport code already has these checks to protect against
sysfs files being writable before module initialization is complete. It
uses the ft_mutex to protect the list of transports(LLDs) so when
'create' is called it knows that the transport is still there to call
down to. It holds the ft_mutex until the LLD's 'create' routine returns.
The transports(LLDs) should be detaching themselves from the fcoe
transport layer before they exit. fcoe_transport_detach will try to
acquire the ft_mutex and block until the 'create' call returns and
releases the ft_mutex. I think this ensures that the transport(LLD) will
be fine when the fcoe transport calls it.

My feeling is that these checks are still needed in the fcoe transport,
but not in the LLDs. If someone can suggest a better way to protect
against writable sysfs files when the module hasn't finished
initializing, we should do that instead of the ifdefs.

Hope this helps,

//Rob

FYI: mnc asked about this code and the trylock code in fcoe and libfcoe.
I have patches in our internal validation to remove the trylock usage,
but I don't have patches to fix the module state checking.

RE: [PATCH] [SCSI] bnx2fc: fix build error when !CONFIG_MODULES

[Zou, Yi]

> On Mon, 2011-03-07 at 16:18 -0800, James Bottomley wrote:
> > On Mon, 2011-03-07 at 15:54 -0800, Bhanu Gollapudi wrote:
> > > On Mon, 2011-03-07 at 12:16 -0800, Mariusz Kozlowski wrote:
> > > > On Wed, Mar 02, 2011 at 11:10:03PM +0100, Mariusz Kozlowski wrote:
> > > > > drivers/scsi/bnx2fc/bnx2fc_fcoe.c:1815: error: dereferencing
> pointer to incomplete type
> > > > > drivers/scsi/bnx2fc/bnx2fc_fcoe.c:1815: error:
> ‘MODULE_STATE_LIVE’ undeclared (first use in this function)
> > > >
> > > > Hm. Still there in next-20110307. Is this patch wrong or..?
> > > >
> > >
> > > James,
> > >
> > > Here is my ack for this patch.
> >
> > OK, so the patch is actually wrong because adding #ifdefs on modules in
> > files really impedes readability.  The bug is using a direct deref on
> > module state instead of one of the APIs which work in the non-modular
> > case, namely try_module_get(). That means the other two need to come
> out
> > and be reworked (plus all the others in fcoe).
> >
> > Reworked looks like it might be a bigger item than bnx2fc.  If any of
> > those tests is ever relevant, it means we have a race in the
> > fcoe_transport because it shouldn't be calling function pointers on a
> > dying module (unless it wants to trigger an oops).
> >
> > So, why are you trying to do this in the first place?
> >
> First, fcoe.c started with these checks. Here is a comment in fcoe.c at
> the point of one of the checks.
> 
> /*
>  * Make sure the module has been initialized, and is not about to be
>  * removed.  Module paramter sysfs files are writable before the
>  * module_init function is called and after module_exit.
>  */
> 
> I don't know the correct way to fix that race is, but we may be past the
> need to fix it in the LLDs.
> 
> Next, the fcoe transport was added. Since it (libfcoe.ko) is now calling
> what used to be the fcoe.ko sysfs entry points I don't think the problem
> exists in fcoe.c or in bnx2fc_fcoe.c, the problem should be in the fcoe
> transport code, as James suggested.
> 
> The fcoe transport code already has these checks to protect against
> sysfs files being writable before module initialization is complete. It
> uses the ft_mutex to protect the list of transports(LLDs) so when
> 'create' is called it knows that the transport is still there to call
> down to. It holds the ft_mutex until the LLD's 'create' routine returns.
> The transports(LLDs) should be detaching themselves from the fcoe
> transport layer before they exit. fcoe_transport_detach will try to
> acquire the ft_mutex and block until the 'create' call returns and
> releases the ft_mutex. I think this ensures that the transport(LLD) will
> be fine when the fcoe transport calls it.
> 
> My feeling is that these checks are still needed in the fcoe transport,
> but not in the LLDs. If someone can suggest a better way to protect
> against writable sysfs files when the module hasn't finished
> initializing, we should do that instead of the ifdefs.
> 
> Hope this helps,
> 
> //Rob
> 
> FYI: mnc asked about this code and the trylock code in fcoe and libfcoe.
> I have patches in our internal validation to remove the trylock usage,
> but I don't have patches to fix the module state checking.
> 
Yeah, this logic was from original fixing race condition in fcoe.ko, note
that we do need check the MODULE_STATE_LIVE, try_module_get() is not what
we wanted, plus module_is_live () checks if it is !GOING. Anyway, I don't
think this is needed any more for individual fcoe transport driver, e.g.,
fcoe.ko or bnx2fc, as the race is now for sysfs of libfcoe.

I will send out a patch to clean up the fcoe.c for this.

Thanks,
yi






> --
> To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

RE: [PATCH] [SCSI] bnx2fc: fix build error when !CONFIG_MODULES

[Bhanu Gollapudi]

On Tue, 2011-03-08 at 11:36 -0800, Zou, Yi wrote: 
> > On Mon, 2011-03-07 at 16:18 -0800, James Bottomley wrote:
> > > On Mon, 2011-03-07 at 15:54 -0800, Bhanu Gollapudi wrote:
> > > > On Mon, 2011-03-07 at 12:16 -0800, Mariusz Kozlowski wrote:
> > > > > On Wed, Mar 02, 2011 at 11:10:03PM +0100, Mariusz Kozlowski wrote:
> > > > > > drivers/scsi/bnx2fc/bnx2fc_fcoe.c:1815: error: dereferencing
> > pointer to incomplete type
> > > > > > drivers/scsi/bnx2fc/bnx2fc_fcoe.c:1815: error:
> > ‘MODULE_STATE_LIVE’ undeclared (first use in this function)
> > > > >
> > > > > Hm. Still there in next-20110307. Is this patch wrong or..?
> > > > >
> > > >
> > > > James,
> > > >
> > > > Here is my ack for this patch.
> > >
> > > OK, so the patch is actually wrong because adding #ifdefs on modules in
> > > files really impedes readability.  The bug is using a direct deref on
> > > module state instead of one of the APIs which work in the non-modular
> > > case, namely try_module_get(). That means the other two need to come
> > out
> > > and be reworked (plus all the others in fcoe).
> > >
> > > Reworked looks like it might be a bigger item than bnx2fc.  If any of
> > > those tests is ever relevant, it means we have a race in the
> > > fcoe_transport because it shouldn't be calling function pointers on a
> > > dying module (unless it wants to trigger an oops).
> > >
> > > So, why are you trying to do this in the first place?
> > >
> > First, fcoe.c started with these checks. Here is a comment in fcoe.c at
> > the point of one of the checks.
> > 
> > /*
> >  * Make sure the module has been initialized, and is not about to be
> >  * removed.  Module paramter sysfs files are writable before the
> >  * module_init function is called and after module_exit.
> >  */
> > 
> > I don't know the correct way to fix that race is, but we may be past the
> > need to fix it in the LLDs.
> > 
> > Next, the fcoe transport was added. Since it (libfcoe.ko) is now calling
> > what used to be the fcoe.ko sysfs entry points I don't think the problem
> > exists in fcoe.c or in bnx2fc_fcoe.c, the problem should be in the fcoe
> > transport code, as James suggested.
> > 
> > The fcoe transport code already has these checks to protect against
> > sysfs files being writable before module initialization is complete. It
> > uses the ft_mutex to protect the list of transports(LLDs) so when
> > 'create' is called it knows that the transport is still there to call
> > down to. It holds the ft_mutex until the LLD's 'create' routine returns.
> > The transports(LLDs) should be detaching themselves from the fcoe
> > transport layer before they exit. fcoe_transport_detach will try to
> > acquire the ft_mutex and block until the 'create' call returns and
> > releases the ft_mutex. I think this ensures that the transport(LLD) will
> > be fine when the fcoe transport calls it.
> > 
> > My feeling is that these checks are still needed in the fcoe transport,
> > but not in the LLDs. If someone can suggest a better way to protect
> > against writable sysfs files when the module hasn't finished
> > initializing, we should do that instead of the ifdefs.
> > 
> > Hope this helps,
> > 
> > //Rob
> > 
> > FYI: mnc asked about this code and the trylock code in fcoe and libfcoe.
> > I have patches in our internal validation to remove the trylock usage,
> > but I don't have patches to fix the module state checking.
> > 
> Yeah, this logic was from original fixing race condition in fcoe.ko, note
> that we do need check the MODULE_STATE_LIVE, try_module_get() is not what
> we wanted, plus module_is_live () checks if it is !GOING. Anyway, I don't
> think this is needed any more for individual fcoe transport driver, e.g.,
> fcoe.ko or bnx2fc, as the race is now for sysfs of libfcoe.
> 
> I will send out a patch to clean up the fcoe.c for this.

I agree. I'll follow it up with bnx2fc patch.

Thanks,
Bhanu 
> 
> Thanks,
> yi
> 
> 
> 
> 
> 
> 
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH] [SCSI] bnx2fc: fix build error when !CONFIG_MODULES

[James Bottomley]

On Mon, 2011-03-07 at 17:09 -0800, Robert Love wrote:
> On Mon, 2011-03-07 at 16:18 -0800, James Bottomley wrote:
> > On Mon, 2011-03-07 at 15:54 -0800, Bhanu Gollapudi wrote:
> > > On Mon, 2011-03-07 at 12:16 -0800, Mariusz Kozlowski wrote: 
> > > > On Wed, Mar 02, 2011 at 11:10:03PM +0100, Mariusz Kozlowski wrote:
> > > > > drivers/scsi/bnx2fc/bnx2fc_fcoe.c:1815: error: dereferencing pointer to incomplete type
> > > > > drivers/scsi/bnx2fc/bnx2fc_fcoe.c:1815: error: ‘MODULE_STATE_LIVE’ undeclared (first use in this function)
> > > > 
> > > > Hm. Still there in next-20110307. Is this patch wrong or..?
> > > > 
> > > 
> > > James,
> > > 
> > > Here is my ack for this patch.
> > 
> > OK, so the patch is actually wrong because adding #ifdefs on modules in
> > files really impedes readability.  The bug is using a direct deref on
> > module state instead of one of the APIs which work in the non-modular
> > case, namely try_module_get(). That means the other two need to come out
> > and be reworked (plus all the others in fcoe).
> > 
> > Reworked looks like it might be a bigger item than bnx2fc.  If any of
> > those tests is ever relevant, it means we have a race in the
> > fcoe_transport because it shouldn't be calling function pointers on a
> > dying module (unless it wants to trigger an oops).
> > 
> > So, why are you trying to do this in the first place?
> > 
> First, fcoe.c started with these checks. Here is a comment in fcoe.c at
> the point of one of the checks.
> 
> /*
>  * Make sure the module has been initialized, and is not about to be
>  * removed.  Module paramter sysfs files are writable before the
>  * module_init function is called and after module_exit.
>  */
> 
> I don't know the correct way to fix that race is, but we may be past the
> need to fix it in the LLDs.

Well, what you've done isn't even fixing the race ... it's just
narrowing the window.  count checks on refcounted objects are almost
always wrong.  To see this just think what happens if the module goes
dead the instruction cycle after you do the check.

I don't understand the problem with the comments above.  The way we
solve the sysfs race in most systems (including modules) is to make sure
they're initialised with the module and torn down as part of its exit
process ... modules.c follows this pattern.  The parameters are supposed
to be initialised before the module has any state (because the init code
may rely on them).

I think the problem is you have what are essentially functional sysfs
files done as module parameters in fcoe_transport.c ... this looks to be
wrong.  What you should have is these added as group attributes once the
module is capable of processing them; that way you control the
lifetimes.

James


> Next, the fcoe transport was added. Since it (libfcoe.ko) is now calling
> what used to be the fcoe.ko sysfs entry points I don't think the problem
> exists in fcoe.c or in bnx2fc_fcoe.c, the problem should be in the fcoe
> transport code, as James suggested.
> 
> The fcoe transport code already has these checks to protect against
> sysfs files being writable before module initialization is complete. It
> uses the ft_mutex to protect the list of transports(LLDs) so when
> 'create' is called it knows that the transport is still there to call
> down to. It holds the ft_mutex until the LLD's 'create' routine returns.
> The transports(LLDs) should be detaching themselves from the fcoe
> transport layer before they exit. fcoe_transport_detach will try to
> acquire the ft_mutex and block until the 'create' call returns and
> releases the ft_mutex. I think this ensures that the transport(LLD) will
> be fine when the fcoe transport calls it.
> 
> My feeling is that these checks are still needed in the fcoe transport,
> but not in the LLDs. If someone can suggest a better way to protect
> against writable sysfs files when the module hasn't finished
> initializing, we should do that instead of the ifdefs.
> 
> Hope this helps,
> 
> //Rob
> 
> FYI: mnc asked about this code and the trylock code in fcoe and libfcoe.
> I have patches in our internal validation to remove the trylock usage,
> but I don't have patches to fix the module state checking.
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH] [SCSI] bnx2fc: fix build error when !CONFIG_MODULES

[Robert Love]

On Thu, 2011-03-10 at 07:32 -0800, James Bottomley wrote:
> On Mon, 2011-03-07 at 17:09 -0800, Robert Love wrote:
> > On Mon, 2011-03-07 at 16:18 -0800, James Bottomley wrote:
> > > On Mon, 2011-03-07 at 15:54 -0800, Bhanu Gollapudi wrote:
> > > > On Mon, 2011-03-07 at 12:16 -0800, Mariusz Kozlowski wrote: 
> > > > > On Wed, Mar 02, 2011 at 11:10:03PM +0100, Mariusz Kozlowski wrote:
> > > > > > drivers/scsi/bnx2fc/bnx2fc_fcoe.c:1815: error: dereferencing pointer to incomplete type
> > > > > > drivers/scsi/bnx2fc/bnx2fc_fcoe.c:1815: error: ‘MODULE_STATE_LIVE’ undeclared (first use in this function)
> > > > > 
> > > > > Hm. Still there in next-20110307. Is this patch wrong or..?
> > > > > 
> > > > 
> > > > James,
> > > > 
> > > > Here is my ack for this patch.
> > > 
> > > OK, so the patch is actually wrong because adding #ifdefs on modules in
> > > files really impedes readability.  The bug is using a direct deref on
> > > module state instead of one of the APIs which work in the non-modular
> > > case, namely try_module_get(). That means the other two need to come out
> > > and be reworked (plus all the others in fcoe).
> > > 
> > > Reworked looks like it might be a bigger item than bnx2fc.  If any of
> > > those tests is ever relevant, it means we have a race in the
> > > fcoe_transport because it shouldn't be calling function pointers on a
> > > dying module (unless it wants to trigger an oops).
> > > 
> > > So, why are you trying to do this in the first place?
> > > 
> > First, fcoe.c started with these checks. Here is a comment in fcoe.c at
> > the point of one of the checks.
> > 
> > /*
> >  * Make sure the module has been initialized, and is not about to be
> >  * removed.  Module paramter sysfs files are writable before the
> >  * module_init function is called and after module_exit.
> >  */
> > 
> > I don't know the correct way to fix that race is, but we may be past the
> > need to fix it in the LLDs.
> 
> Well, what you've done isn't even fixing the race ... it's just
> narrowing the window.  count checks on refcounted objects are almost
> always wrong.  To see this just think what happens if the module goes
> dead the instruction cycle after you do the check.
> 
> I don't understand the problem with the comments above.  The way we
> solve the sysfs race in most systems (including modules) is to make sure
> they're initialised with the module and torn down as part of its exit
> process ... modules.c follows this pattern.  The parameters are supposed
> to be initialised before the module has any state (because the init code
> may rely on them).
> 
> I think the problem is you have what are essentially functional sysfs
> files done as module parameters in fcoe_transport.c ... this looks to be
> wrong.  What you should have is these added as group attributes once the
> module is capable of processing them; that way you control the
> lifetimes.

You're right, this is our problem. Unfortunately, we're in a bit of a
"chicken and egg" situation.

For SW FCoE, we don't know which netdevice the user wants to run FCoE
traffic on so we don't create any devices or other sysfs entries until
the user tells us to 'create'. The user passes the netdevice name to our
sysfs file and then we create the scsi_host/fc_host.

I am not sure what I would attach a group of attributes (create,
destroy, etc...) to. If I had per-instance devices I could add
attributes to them, but I need the 'create' interface before I can
create any per-instance devices.

One option would be to go back to what we used to do (pre-mainline
acceptance) which is the following:

static const struct kobj_attribute fcoe_destroyattr = \
	__ATTR(destroy, S_IWUSR, NULL, fcoe_destroy);
static const struct kobj_attribute fcoe_createattr = \
	__ATTR(create, S_IWUSR, NULL, fcoe_create);

static int __init fcoe_init(void)
{
...
rc = sysfs_create_file(&THIS_MODULE->mkobj.kobj,
		       &fcoe_destroyattr.attr);
if (!rc)
	rc = sysfs_create_file(&THIS_MODULE->mkobj.kobj,
			       &fcoe_createattr.attr)
...
}

I think this is bad because we're manipulating kobjects too directly,
right?

A second option would be to keep everything the same but use an atomic
bit to signify when the module has completed initialization. We'd still
need a check in each of the sysfs entries store routines, but we
wouldn't be checking against the module state.

A third option is to do something like bonding does, where it creates
a /sys/class/net/bonding_masters entry. My guess is that this would be
controversial; adding fcoe interfaces class/net could be considered
polluting the networking space with storage information.

A fourth option would be to drop sysfs all together and use netlink,
like iSCSI. Currently we don't need an extensive kernel/user interface,
so I look at this as overkill.

I suppose the second option would solve the current race. I realize it
doesn't necessarily fix the fact that we're adding usable sysfs files
prematurely, but I'm not sure where I'd attach the attributes if I were
do do it at the end of libfcoe's module_init routine. I'll mail my patch
for comments.

Thanks, //Rob