Re: [Patch rdma-next] RDMA/mana_ib: handle net event for pointing to the current netdev

[Ratheesh Kannoth <rkannoth@marvell.com>]

On 2025-03-01 at 04:11:59, longli@linuxonhyperv.com (longli@linuxonhyperv.com) wrote:
> From: Long Li <longli@microsoft.com>
>
> When running under Hyper-V, the master device to the RDMA device is always
> bonded to this RDMA device if it's present in the kernel. This is not
> user-configurable.
>
> The master device can be unbind/bind from the kernel. During those events,
> the RDMA device should set to the current netdev to relect the change of
> master device from those events.
>
> Signed-off-by: Long Li <longli@microsoft.com>
> ---
>  drivers/infiniband/hw/mana/device.c  | 35 ++++++++++++++++++++++++++++
>  drivers/infiniband/hw/mana/mana_ib.h |  1 +
>  2 files changed, 36 insertions(+)
>
> diff --git a/drivers/infiniband/hw/mana/device.c b/drivers/infiniband/hw/mana/device.c
> index 3416a85f8738..3e4f069c2258 100644
> --- a/drivers/infiniband/hw/mana/device.c
> +++ b/drivers/infiniband/hw/mana/device.c
> @@ -51,6 +51,37 @@ static const struct ib_device_ops mana_ib_dev_ops = {
>  			   ib_ind_table),
>  };
>
> +static int mana_ib_netdev_event(struct notifier_block *this,
> +				unsigned long event, void *ptr)
> +{
> +	struct mana_ib_dev *dev = container_of(this, struct mana_ib_dev, nb);
> +	struct net_device *event_dev = netdev_notifier_info_to_dev(ptr);
> +	struct gdma_context *gc = dev->gdma_dev->gdma_context;
> +	struct mana_context *mc = gc->mana.driver_data;
> +	struct net_device *ndev;
> +
> +	if (event_dev != mc->ports[0])
> +		return NOTIFY_DONE;
> +
> +	switch (event) {
> +	case NETDEV_CHANGEUPPER:
> +		rcu_read_lock();
> +		ndev = mana_get_primary_netdev_rcu(mc, 0);
> +		rcu_read_unlock();
...
> +
> +		/*
> +		 * RDMA core will setup GID based on updated netdev.
> +		 * It's not possible to race with the core as rtnl lock is being
> +		 * held.
> +		 */
> +		ib_device_set_netdev(&dev->ib_dev, ndev, 1);
rcu_read_unlock() should be here, right ?
> +
> +		return NOTIFY_OK;
> +	default:
> +		return NOTIFY_DONE;
> +	}
> +}
> +
>