Subject: Re: [PATCH net-next v2 2/3] net: dsa: integrate with SWITCHDEV for HW bridging

From: Florian Fainelli <[email-masked]>
Date: Tue, 24 Feb 2015 12:49:35 -0800

On 24/02/15 12:43, Guenter Roeck wrote:
> Hi Florian,
> 
> On Tue, Feb 24, 2015 at 12:08:30PM -0800, Florian Fainelli wrote:
>> In order to support bridging offloads in DSA switch drivers, select
>> NET_SWITCHDEV to get access to the port_stp_update and parent_get_id
>> NDOs that we are required to implement.
>>
>> To facilitate the integratation at the DSA driver level, we implement 3
>> types of operations:
>>
>> - port_join_bridge
>> - port_leave_bridge
>> - port_stp_update
>>
>> DSA will resolve which switch ports that are currently bridge port
>> members as some Switch hardware/drivers need to know about that to limit
>> the register programming to just the relevant registers (especially for
>> slow MDIO buses).
>>
>> We also take care of setting the correct STP state when slave network
>> devices are brought up/down while being bridge members.
>>
>> Finally, when a port is leaving the bridge, we make sure we set in
>> BR_STATE_FORWARDING state, otherwise the bridge layer would leave it
>> disabled as a result of having left the bridge.
>>
>> Signed-off-by: Florian Fainelli <[email-masked]>
>> ---
> [ ... ]
> 
>>  
>> +/* Return a bitmask of all ports being currently bridged within a given bridge
>> + * device. Note that on leave, the mask will still return the bitmask of ports
>> + * currently bridged, prior to port removal, and this is exactly what we want.
>> + */
>> +static u32 dsa_slave_br_port_mask(struct dsa_switch *ds,
>> +				  struct net_device *bridge)
>> +{
>> +	struct dsa_slave_priv *p;
>> +	unsigned int port;
>> +	u32 mask = 0;
>> +
>> +	for (port = 0; port < DSA_MAX_PORTS; port++) {
>> +		if (!((1 << port) & ds->phys_port_mask))
>> +			continue;
>> +
>> +		p = netdev_priv(ds->ports[port]);
>> +
> 
> ds->ports[port] can still be NULL here since the function can be called
> before all ports are initialized (which is what I had actually seen).

Can it now? I re-ordered the patches such that your change comes first
(and I forgot to update the commit message) and by the time we get
called from register_netdev(), ds->ports[port] has already been assigned.

Am I missing something here?
--
Florian