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Subject: Re: [PATCH RFC net-next 7/7] netdevsim: Add simple FIB resource
 controller via devlink
To: Jiri Pirko <jiri@resnulli.us>
Cc: netdev@vger.kernel.org, davem@davemloft.net,
        roopa@cumulusnetworks.com, shm@cumulusnetworks.com,
        jiri@mellanox.com, idosch@mellanox.com,
        jakub.kicinski@netronome.com, David Ahern <dsahern@gmail.com>
References: <20180322225757.10377-1-dsa@cumulusnetworks.com>
 <20180322225757.10377-8-dsa@cumulusnetworks.com>
 <20180323065010.GM2074@nanopsycho.orion>
 <03eade79-1727-3a31-8e31-a0a7f51b72cf@cumulusnetworks.com>
 <20180323150149.GD2125@nanopsycho>
 <e7900c83-3dbd-5e7a-57ec-2647e0371e75@cumulusnetworks.com>
 <20180323150516.GE2125@nanopsycho>
From: David Ahern <dsa@cumulusnetworks.com>
Message-ID: <fe5a4e1f-5681-4d74-b586-0c727eed717e@cumulusnetworks.com>
Date: Fri, 23 Mar 2018 09:13:14 -0600
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On 3/23/18 9:05 AM, Jiri Pirko wrote:
> Fri, Mar 23, 2018 at 04:03:40PM CET, dsa@cumulusnetworks.com wrote:
>> On 3/23/18 9:01 AM, Jiri Pirko wrote:
>>> Fri, Mar 23, 2018 at 03:31:02PM CET, dsa@cumulusnetworks.com wrote:
>>>> On 3/23/18 12:50 AM, Jiri Pirko wrote:
>>>>>> +void nsim_devlink_setup(struct netdevsim *ns)
>>>>>> +{
>>>>>> +	struct net *net = dev_net(ns->netdev);
>>>>>> +	bool *reg_devlink = net_generic(net, nsim_devlink_id);
>>>>>> +	struct devlink *devlink;
>>>>>> +	int err = -ENOMEM;
>>>>>> +
>>>>>> +	/* only one device per namespace controls devlink */
>>>>>> +	if (!*reg_devlink) {
>>>>>> +		ns->devlink = NULL;
>>>>>> +		return;
>>>>>> +	}
>>>>>> +
>>>>>> +	devlink = devlink_alloc(&nsim_devlink_ops, 0);
>>>>>> +	if (!devlink)
>>>>>> +		return;
>>>>>> +
>>>>>> +	devlink_net_set(devlink, net);
>>>>>> +	err = devlink_register(devlink, &ns->dev);
>>>>>
>>>>> This reg_devlink construct looks odd. Why don't you leave the devlink
>>>>> instance in init_ns?
>>>>
>>>> It is a per-network namespace resource controller. Since struct devlink
>>>
>>> Wait a second. What do you mean by "per-network namespace"? Devlink
>>> instance is always associated with one physical device. Like an ASIC.
>>>
>>>
>>>> has a net entry, the simplest design is to put it into the namespace of
>>>> the controller. Without it, controlling resource sizes in namespace
>>>> 'foobar' has to be done from init_net, which is just wrong.
>>
>> you need to look at how netdevsim creates a device per netdevice.
> 
> That means one devlink instance for each netdevsim device, doesn't it?
> 

yes.