Re: [PATCH for-next v1] RDMA/nldev: Add support for reporting ipoib netdev

[Jason Gunthorpe <jgg@ziepe.ca>]

On Fri, Sep 15, 2023 at 02:37:57PM -0400, Kamal Heib wrote:
> This patch adds support for reporting the ipoib net device for a given
> RDMA device by calling ib_get_net_dev_by_params() when filling the
> port's info.
> 
> $ rdma link show mlx5_0/1
> link mlx5_0/1 subnet_prefix fe80:0000:0000:0000 lid 66 sm_lid 3 lmc 0
> 	state ACTIVE physical_state LINK_UP netdev ibp196s0f0
> 
> Signed-off-by: Kamal Heib <kheib@redhat.com>
> ---
> v1: Check namespace and query pkey.
> ---
>  drivers/infiniband/core/nldev.c | 27 ++++++++++++++++++++++++++-
>  1 file changed, 26 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
> index d5d3e4f0de77..f3fa8143cdc7 100644
> --- a/drivers/infiniband/core/nldev.c
> +++ b/drivers/infiniband/core/nldev.c
> @@ -308,10 +308,12 @@ static int fill_port_info(struct sk_buff *msg,
>  			  struct ib_device *device, u32 port,
>  			  const struct net *net)
>  {
> +	struct net_device *ipoib_netdev = NULL;
>  	struct net_device *netdev = NULL;
>  	struct ib_port_attr attr;
> -	int ret;
>  	u64 cap_flags = 0;
> +	u16 pkey;
> +	int ret;
>  
>  	if (fill_nldev_handle(msg, device))
>  		return -EMSGSIZE;
> @@ -340,6 +342,26 @@ static int fill_port_info(struct sk_buff *msg,
>  			return -EMSGSIZE;
>  		if (nla_put_u8(msg, RDMA_NLDEV_ATTR_LMC, attr.lmc))
>  			return -EMSGSIZE;
> +
> +		ret = ib_query_pkey(device, port, 0, &pkey);
> +		if (ret)
> +			goto out;

That doesn't really make any sense..

The whole idea there is only one ipoib device doesn't even make sense.

I still don't like this at all.

> +
> +		ipoib_netdev = ib_get_net_dev_by_params(device, port,
> +							pkey,
> +							NULL, NULL);
> +		if (ipoib_netdev && net_eq(dev_net(ipoib_netdev), net)) {
> +			ret = nla_put_u32(msg,
> +					  RDMA_NLDEV_ATTR_NDEV_INDEX,
> +					  ipoib_netdev->ifindex);
> +			if (ret)
> +				goto out;
> +			ret = nla_put_string(msg,
> +					     RDMA_NLDEV_ATTR_NDEV_NAME,
> +					     ipoib_netdev->name);
> +			if (ret)
> +				goto out;

and I don't think the existing netlink attributes should be redefined
to be about ipoib

Jason