Re: [RFC PATCH net-next 1/5] net: bridge: add dynamic flag to switchdev notifier

[netdev@kapio-technology.com]

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
>>