From: Arvid Brodin <arvid.brodin@xdin•com>
To: Stephen Hemminger <stephen@networkplumber•org>
Cc: "netdev@vger•kernel.org" <netdev@vger•kernel.org>,
Joe Perches <joe@perches•com>,
Javier Boticario <jboticario@gmail•com>,
"balferreira@googlemail•com" <balferreira@googlemail•com>,
Arvid Brodin <Arvid.Brodin@xdin•com>
Subject: Re: [PATCH] net/hsr: Add support for the High-availability Seamless Redundancy protocol (HSRv0)
Date: Wed, 26 Jun 2013 01:36:47 +0200 [thread overview]
Message-ID: <51CA298F.7060600@xdin.com> (raw)
In-Reply-To: <20130625154638.357e4764@nehalam.linuxnetplumber.net>
On 2013-06-26 00:46, Stephen Hemminger wrote:
> On Wed, 26 Jun 2013 00:30:51 +0200
> Arvid Brodin <arvid.brodin@xdin•com> wrote:
>
>> On 2013-06-25 02:07, Stephen Hemminger wrote:
>>> On Mon, 24 Jun 2013 09:44:01 -0700
>>> Arvid Brodin <arvid.brodin@xdin•com> wrote:
>>>
>>>> +
>>>> +
>>>> +static bool is_admin_up(struct net_device *dev)
>>>> +{
>>>> + return dev && (dev->flags & IFF_UP);
>>>> +}
>>>> +
>>>> +static bool is_operstate_up(struct net_device *dev)
>>>> +{
>>>> + return (dev && (dev->operstate == IF_OPER_UP));
>>>> +}
>>>> +
>>>
>>> Isn't is_admin_up the same as netif_running()?
>>
>> I don't think so (but I'm unsure). This is netif_running() (from include/linux/netdevice.h):
>>
>> static inline bool netif_running(const struct net_device *dev)
>> {
>> return test_bit(__LINK_STATE_START, &dev->state);
>> }
>>
>> I'm not sure what this does. I don't think it's the same as checking whether the admin has
>> issued an UP command?
>>
>>
>>> And is_operstate_up the same as netif_oper_up()?
>>
>> netif_oper_up() also returns true if the device state is IF_OPER_UNKNOWN. A device can
>> have that state without even having carrier, so that's not OK for the HSR driver.
>>
>
> Then use netif_oper_up(dev) && netif_carrier_on(dev)
That would be very weird since netif_carrier_on() signals that the carrier is on (and
returns void). :) But I get your point - i.e. check for carrier state.
This is netif_oper_up() in include/linux/netdevice.h:
static inline bool netif_oper_up(const struct net_device *dev)
{
return (dev->operstate == IF_OPER_UP ||
dev->operstate == IF_OPER_UNKNOWN /* backward compat */);
}
I'm guessing that IF_OPER_UNKNOWN is just a default state and that some (old or buggy)
network drivers simply does not set this as they should? I.e. they should call
netif_carrier_off() on open, but they don't. The "backward compat" may be a way around
that? (We had problems with this on an old version of the macb driver; I think that's why
we wrote our own is_operstate_up().)
If so, I guess you are right and I should use netif_oper_up() (and any problems arising
from that would be due to bugs in the respective device driver). Does this sound reasonable?
--
Arvid Brodin | Consultant (Linux)
T: +46-8-56254286 | M: +46-70-9714286 | arvid.brodin@xdin•com
XDIN AB | Knarrarnäsgatan 7 | SE-164 40 Kista | Sweden | xdin.com
next prev parent reply other threads:[~2013-06-25 23:36 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1902752B0C92F943AB7EA9EE13E2DEEC126CC8C873@HQ1-EXCH02.corp.brocade.com>
[not found] ` <20130624170727.4d7893a1@nehalam.linuxnetplumber.net>
2013-06-25 22:30 ` [PATCH] net/hsr: Add support for the High-availability Seamless Redundancy protocol (HSRv0) Arvid Brodin
2013-06-25 22:46 ` Stephen Hemminger
2013-06-25 23:36 ` Arvid Brodin [this message]
[not found] ` <20130624171151.7b2b342a@nehalam.linuxnetplumber.net>
2013-06-25 22:57 ` Arvid Brodin
2013-06-24 16:43 Arvid Brodin
2013-06-24 18:16 ` Joe Perches
2013-06-25 21:16 ` Arvid Brodin
2013-06-25 21:31 ` Joe Perches
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