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Date: Fri, 23 Mar 2018 16:01:49 +0100
From: Jiri Pirko <jiri@resnulli.us>
To: David Ahern <dsa@cumulusnetworks.com>
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>
Subject: Re: [PATCH RFC net-next 7/7] netdevsim: Add simple FIB resource
 controller via devlink
Message-ID: <20180323150149.GD2125@nanopsycho>
References: <20180322225757.10377-1-dsa@cumulusnetworks.com>
 <20180322225757.10377-8-dsa@cumulusnetworks.com>
 <20180323065010.GM2074@nanopsycho.orion>
 <03eade79-1727-3a31-8e31-a0a7f51b72cf@cumulusnetworks.com>
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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.