Re: [PATCH rdma-next v2 09/11] RDMA/erdma: Add the erdma module

[Leon Romanovsky <leon@kernel.org>]

On Tue, Jan 18, 2022 at 11:29:34AM +0800, Cheng Xu wrote:
> 
> 
> On 1/17/22 11:22 PM, Jason Gunthorpe wrote:
> > On Mon, Jan 17, 2022 at 04:48:26PM +0800, Cheng Xu wrote:
> > > Add the main erdma module and debugfs files. The main module provides
> > > interface to infiniband subsytem, and the debugfs module provides a way
> > > to allow user can get the core status of the device and set the preferred
> > > congestion control algorithm.

<...>

> > 
> > > +static __init int erdma_init_module(void)
> > > +{
> > > +	int ret;
> > > +
> > > +	ret = erdma_cm_init();
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	ret = pci_register_driver(&erdma_pci_driver);
> > > +	if (ret) {
> > > +		pr_err("Couldn't register erdma driver.\n");
> > > +		goto uninit_cm;
> > > +	}
> > > +
> > > +	ret = register_netdevice_notifier(&erdma_netdev_nb);
> > > +	if (ret)
> > > +		goto unregister_driver;
> > 
> > And notifiers should not be registered without devices.
> 
> I'm confused about this. irdma/bnxt_re/siw/rxe register net notifiers in
> their module_init, and get their ibdev structures by function
> 'ib_device_get_by_netdev'. Other drivers (mlx4/mlx5/hns) register notifiers
> with devices.

Let's put siw and RXE aside, they are special. Regarding irdma - it is a
bug and its register notifier logic should be in driver init code. It
will ensure that notifications are received only when the ib device is
ready.

And for the bnxt_re case, I didn't look too closely on why it is written
how it is written.

Thanks