From: Jarod Wilson <jarod@redhat.com>
To: Alexander Duyck <alexander.duyck@gmail.com>
Cc: linux-kernel@vger.kernel.org,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jay Vosburgh <j.vosburgh@gmail.com>,
Veaceslav Falico <vfalico@gmail.com>,
Andy Gospodarek <gospo@cumulusnetworks.com>,
Jiri Pirko <jiri@resnulli.us>,
Nikolay Aleksandrov <razor@blackwall.org>,
Michal Kubecek <mkubecek@suse.cz>,
netdev@vger.kernel.org
Subject: Re: [PATCH net-next] net/core: ensure features get disabled on new lower devs
Date: Tue, 03 Nov 2015 17:11:51 -0500 [thread overview]
Message-ID: <56393127.4050406@redhat.com> (raw)
In-Reply-To: <5639245D.7000501@gmail.com>
Alexander Duyck wrote:
> On 11/03/2015 12:36 PM, Jarod Wilson wrote:
>> With moving netdev_sync_lower_features() after the .ndo_set_features
>> calls, I neglected to verify that devices added *after* a flag had been
>> disabled on an upper device were properly added with that flag
>> disabled as
>> well. This currently happens, because we exit __netdev_update_features()
>> when we see dev->features == features for the upper dev. We can retain
>> the
>> optimization of leaving without calling .ndo_set_features with a bit of
>> tweaking and a goto here.
>>
>> Changing err to ret was somewhat arbitrary and makes the patch look more
>> involved, but seems to better fit the altered use.
...
>> + if (!ret) {
>> + dev->features = features;
>> + ret = 1;
>> + }
>> +
>
> I would take the "ret = 1;" out of the if statement and let it stay here
> by itself. Technically anything that traversed this path was returning 1
> previously so we probably want to retain that behavior.
Ah, that. I took a look at all the callers of __netdev_update_features,
and most don't even check return value, the one that does
(netdev_update_features) only cares if its zero or not zero, so I
figured it didn't really matter here, but it would indeed return 2 now
instead of 1, if it got that from ndo_set_features. For consistency's
sake, I can respin and just always set ret = 1 though.
>> +sync_lower:
>> /* some features must be disabled on lower devices when disabled
>> * on an upper device (think: bonding master or bridge)
>> */
>> netdev_for_each_lower_dev(dev, lower, iter)
>> netdev_sync_lower_features(dev, lower, features);
>>
>> - if (!err)
>> - dev->features = features;
>
> You could just alter the if statement here to check for a non-zero ret
> value since you should have it as either 0 or 1. It shouldn't have any
> other values.
>
> That way you will have disabled the feature on the lower devices before
> advertising that it has been disabled on the upper device.
If this check is down here, the goto will trigger, setting dev->features
= features, but then, we got there because dev->features == features
already, so meh. But it would also NOT trigger in the case of
ndo_set_features returning 0 anymore, because we set ret = 1. Or am I
missing something or misunderstanding what you're suggesting here?
--
Jarod Wilson
jarod@redhat.com
next prev parent reply other threads:[~2015-11-03 22:11 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-24 3:40 [RFC PATCH net-next] net/core: initial support for stacked dev feature toggles Jarod Wilson
2015-10-24 4:41 ` Tom Herbert
2015-10-24 5:51 ` Alexander Duyck
2015-10-26 9:42 ` Michal Kubecek
2015-10-30 16:25 ` Jarod Wilson
2015-10-30 20:02 ` Alexander Duyck
2015-11-02 17:37 ` Jarod Wilson
2015-10-30 16:35 ` Jarod Wilson
2015-10-30 20:14 ` Alexander Duyck
2015-11-02 17:53 ` [PATCH net-next] net/core: generic support for disabling netdev features down stack Jarod Wilson
2015-11-02 18:04 ` Alexander Duyck
2015-11-02 21:57 ` Jarod Wilson
2015-11-03 2:55 ` [PATCH v2 " Jarod Wilson
2015-11-03 4:41 ` David Miller
2015-11-03 10:03 ` Nikolay Aleksandrov
2015-11-03 13:52 ` Geert Uytterhoeven
2015-11-03 13:57 ` Jarod Wilson
2015-11-03 14:05 ` Nikolay Aleksandrov
2015-11-03 15:18 ` Jarod Wilson
2015-11-03 15:15 ` [PATCH net-next] net/core: fix for_each_netdev_feature Jarod Wilson
2015-11-03 15:33 ` Nikolay Aleksandrov
2015-11-03 16:34 ` David Miller
2015-11-03 20:36 ` [PATCH net-next] net/core: ensure features get disabled on new lower devs Jarod Wilson
2015-11-03 21:17 ` Alexander Duyck
2015-11-03 22:11 ` Jarod Wilson [this message]
2015-11-03 23:01 ` Alexander Duyck
2015-11-03 21:21 ` Nikolay Aleksandrov
2015-11-03 21:53 ` Michal Kubecek
2015-11-03 21:58 ` Jarod Wilson
2015-11-04 4:09 ` [PATCH v2 " Jarod Wilson
2015-11-05 2:56 ` David Miller
2015-11-13 0:26 ` Florian Fainelli
2015-11-13 10:29 ` Jiri Pirko
2015-11-13 10:51 ` Nikolay Aleksandrov
2015-11-13 13:54 ` [PATCH net] net: fix feature changes on devices without ndo_set_features Nikolay Aleksandrov
2015-11-13 14:00 ` Jiri Pirko
2015-11-13 14:06 ` Andy Gospodarek
2015-11-13 14:34 ` Jarod Wilson
2015-11-13 18:30 ` Florian Fainelli
2015-11-15 7:25 ` [net] " Dave Young
2015-11-16 2:01 ` Dave Young
2015-11-16 19:56 ` [PATCH net] " David Miller
2015-11-17 23:03 ` Sergei Shtylyov
2015-11-17 23:10 ` Nikolay Aleksandrov
2015-11-18 10:51 ` Sergei Shtylyov
2015-11-13 22:31 ` [PATCH v2 net-next] net/core: ensure features get disabled on new lower devs Laura Abbott
2015-11-17 9:02 ` Geert Uytterhoeven
2015-11-17 10:04 ` Geert Uytterhoeven
2016-04-02 2:21 ` [PATCH v2 net-next] net/core: generic support for disabling netdev features down stack Michał Mirosław
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