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Date:   Wed, 18 Jan 2023 23:14:00 +0100
From:   netdev@kapio-technology.com
To:     Vladimir Oltean <olteanv@gmail.com>
Cc:     davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org,
        Florian Fainelli <f.fainelli@gmail.com>,
        Andrew Lunn <andrew@lunn.ch>,
        Eric Dumazet <edumazet@google.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Kurt Kanzenbach <kurt@linutronix.de>,
        Hauke Mehrtens <hauke@hauke-m.de>,
        Woojung Huh <woojung.huh@microchip.com>,
        "maintainer:MICROCHIP KSZ SERIES ETHERNET SWITCH DRIVER" 
        <UNGLinuxDriver@microchip.com>, Sean Wang <sean.wang@mediatek.com>,
        Landen Chao <Landen.Chao@mediatek.com>,
        DENG Qingfang <dqfext@gmail.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Claudiu Manoil <claudiu.manoil@nxp.com>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        =?UTF-8?Q?Cl=C3=A9ment_L=C3=A9ger?= <clement.leger@bootlin.com>,
        Jiri Pirko <jiri@resnulli.us>,
        Ivan Vecera <ivecera@redhat.com>,
        Roopa Prabhu <roopa@nvidia.com>,
        Nikolay Aleksandrov <razor@blackwall.org>,
        Russell King <linux@armlinux.org.uk>,
        Christian Marangi <ansuelsmth@gmail.com>,
        open list <linux-kernel@vger.kernel.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-arm-kernel@lists.infradead.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>,
        "open list:RENESAS RZ/N1 A5PSW SWITCH DRIVER" 
        <linux-renesas-soc@vger.kernel.org>,
        "moderated list:ETHERNET BRIDGE" <bridge@lists.linux-foundation.org>
Subject: Re: [RFC PATCH net-next 1/5] net: bridge: add dynamic flag to
 switchdev notifier
In-Reply-To: <20230117230806.ipwcbnq4jcc4qs7z@skbuf>
References: <20230117185714.3058453-1-netdev@kapio-technology.com>
 <20230117185714.3058453-2-netdev@kapio-technology.com>
 <20230117230806.ipwcbnq4jcc4qs7z@skbuf>
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On 2023-01-18 00:08, Vladimir Oltean wrote:
> On Tue, Jan 17, 2023 at 07:57:10PM +0100, Hans J. Schultz wrote:
>> To be able to add dynamic FDB entries to drivers from userspace, the
>> dynamic flag must be added when sending RTM_NEWNEIGH events down.
>> 
>> Signed-off-by: Hans J. Schultz <netdev@kapio-technology.com>
>> ---
>>  include/net/switchdev.h   | 1 +
>>  net/bridge/br_switchdev.c | 1 +
>>  2 files changed, 2 insertions(+)
>> 
>> diff --git a/include/net/switchdev.h b/include/net/switchdev.h
>> index ca0312b78294..aaf918d4ba67 100644
>> --- a/include/net/switchdev.h
>> +++ b/include/net/switchdev.h
>> @@ -249,6 +249,7 @@ struct switchdev_notifier_fdb_info {
>>  	u8 added_by_user:1,
>>  	   is_local:1,
>>  	   locked:1,
>> +	   is_dyn:1,
>>  	   offloaded:1;
>>  };
>> 
>> diff --git a/net/bridge/br_switchdev.c b/net/bridge/br_switchdev.c
>> index 7eb6fd5bb917..60c05a00a1df 100644
>> --- a/net/bridge/br_switchdev.c
>> +++ b/net/bridge/br_switchdev.c
>> @@ -136,6 +136,7 @@ static void br_switchdev_fdb_populate(struct 
>> net_bridge *br,
>>  	item->added_by_user = test_bit(BR_FDB_ADDED_BY_USER, &fdb->flags);
>>  	item->offloaded = test_bit(BR_FDB_OFFLOADED, &fdb->flags);
>>  	item->is_local = test_bit(BR_FDB_LOCAL, &fdb->flags);
>> +	item->is_dyn = !test_bit(BR_FDB_STATIC, &fdb->flags);
> 
> Why reverse logic? Why not just name this "is_static" and leave any
> further interpretations up to the consumer?
> 

My reasoning for this is that the common case is to have static entries, 
thus is_dyn=false, so whenever someone uses a 
switchdev_notifier_fdb_info struct the common case does not need to be 
entered.
Otherwise it might also break something when someone uses this struct 
and if it was 'is_static' and they forget to code is_static=true they 
will get dynamic entries without wanting it and it can be hard to find 
such an error.

>>  	item->locked = false;
>>  	item->info.dev = (!p || item->is_local) ? br->dev : p->dev;
>>  	item->info.ctx = ctx;
>> --
>> 2.34.1
>>