Re: Finding the namespace of a struct ib_device

[Jason Gunthorpe <jgg@ziepe.ca>]

On Fri, Sep 04, 2020 at 12:01:12PM +0800, Ka-Cheong Poon wrote:
> On 9/4/20 1:39 AM, Jason Gunthorpe wrote:
> > On Thu, Sep 03, 2020 at 10:02:01PM +0800, Ka-Cheong Poon wrote:
> > > When a struct ib_client's add() function is called. is there a
> > > supported method to find out the namespace of the passed in
> > > struct ib_device?  There is rdma_dev_access_netns() but it does
> > > not return the namespace.  It seems that it needs to have
> > > something like the following.
> > > 
> > > struct net *rdma_dev_to_netns(struct ib_device *ib_dev)
> > > {
> > >         return read_pnet(&ib_dev->coredev.rdma_net);
> > > }
> > > 
> > > Comments?
> > 
> > I suppose, but why would something need this?
> 
> 
> If the client needs to allocate stuff for the namespace
> related to that device, it needs to know the namespace of
> that device.  Then when that namespace is deleted, the
> client can clean up those related stuff as the client's
> namespace exit function can be called before the remove()
> function is triggered in rdma_dev_exit_net().  Without
> knowing the namespace of that device, coordination cannot
> be done.

Since each device can only be in one namespace, why would a client
ever need to allocate at a level more granular than a device?

Jason