Re: [PATCHv5 for-rc1 v5 4/8] RDMA/rxe: Implement dellink in rxe

[Bob Pearson <rpearsonhpe@gmail.com>]

On 4/28/23 04:39, Zhu Yanjun wrote:
> From: Zhu Yanjun <yanjun.zhu@linux.dev>
> 
> When running "rdma link del" command, dellink function will be called.
> If the sock refcnt is greater than the refcnt needed for udp tunnel,
> the sock refcnt will be decreased by 1.
> 
> If equal, the last rdma link is removed. The udp tunnel will be
> destroyed.
> 
> Tested-by: Rain River <rain.1986.08.12@gmail.com>
> Signed-off-by: Zhu Yanjun <yanjun.zhu@linux.dev>
> ---
>  drivers/infiniband/sw/rxe/rxe.c     | 12 +++++++++++-
>  drivers/infiniband/sw/rxe/rxe_net.c | 17 +++++++++++++++--
>  drivers/infiniband/sw/rxe/rxe_net.h |  1 +
>  3 files changed, 27 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/infiniband/sw/rxe/rxe.c b/drivers/infiniband/sw/rxe/rxe.c
> index 0ce6adb43cfc..ebfabc6d6b76 100644
> --- a/drivers/infiniband/sw/rxe/rxe.c
> +++ b/drivers/infiniband/sw/rxe/rxe.c
> @@ -166,10 +166,12 @@ void rxe_set_mtu(struct rxe_dev *rxe, unsigned int ndev_mtu)
>  /* called by ifc layer to create new rxe device.
>   * The caller should allocate memory for rxe by calling ib_alloc_device.
>   */
> +static struct rdma_link_ops rxe_link_ops;
>  int rxe_add(struct rxe_dev *rxe, unsigned int mtu, const char *ibdev_name)
>  {
>  	rxe_init(rxe);
>  	rxe_set_mtu(rxe, mtu);
> +	rxe->ib_dev.link_ops = &rxe_link_ops;
>  
>  	return rxe_register_device(rxe, ibdev_name);
>  }
> @@ -206,9 +208,17 @@ static int rxe_newlink(const char *ibdev_name, struct net_device *ndev)
>  	return err;
>  }
>  
> -struct rdma_link_ops rxe_link_ops = {
> +static int rxe_dellink(struct ib_device *dev)
> +{
> +	rxe_net_del(dev);
> +
> +	return 0;
> +}
> +
> +static struct rdma_link_ops rxe_link_ops = {
>  	.type = "rxe",
>  	.newlink = rxe_newlink,
> +	.dellink = rxe_dellink,
>  };
>  
>  static int __init rxe_module_init(void)
> diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c
> index 3ca92e062800..4cc7de7b115b 100644
> --- a/drivers/infiniband/sw/rxe/rxe_net.c
> +++ b/drivers/infiniband/sw/rxe/rxe_net.c
> @@ -530,6 +530,21 @@ int rxe_net_add(const char *ibdev_name, struct net_device *ndev)
>  	return 0;
>  }
>  
> +#define SK_REF_FOR_TUNNEL	2
> +void rxe_net_del(struct ib_device *dev)
> +{
> +	if (refcount_read(&recv_sockets.sk6->sk->sk_refcnt) > SK_REF_FOR_TUNNEL)
> +		__sock_put(recv_sockets.sk6->sk);
> +	else
> +		rxe_release_udp_tunnel(recv_sockets.sk6);
> +
> +	if (refcount_read(&recv_sockets.sk4->sk->sk_refcnt) > SK_REF_FOR_TUNNEL)
> +		__sock_put(recv_sockets.sk4->sk);
> +	else
> +		rxe_release_udp_tunnel(recv_sockets.sk4);
> +}
> +#undef SK_REF_FOR_TUNNEL
> +
>  static void rxe_port_event(struct rxe_dev *rxe,
>  			   enum ib_event_type event)
>  {
> @@ -689,8 +704,6 @@ int rxe_register_notifier(void)
>  
>  void rxe_net_exit(void)
>  {
> -	rxe_release_udp_tunnel(recv_sockets.sk6);
> -	rxe_release_udp_tunnel(recv_sockets.sk4);
>  	unregister_netdevice_notifier(&rxe_net_notifier);
>  }
These calls are moved to rxe_net_del which is called by an explicit unlink command.
But if rxe_net_init fails and returns an error code this will never happen.
This will result in leaking resources.

Bob
>  
> diff --git a/drivers/infiniband/sw/rxe/rxe_net.h b/drivers/infiniband/sw/rxe/rxe_net.h
> index a222c3eeae12..f48f22f3353b 100644
> --- a/drivers/infiniband/sw/rxe/rxe_net.h
> +++ b/drivers/infiniband/sw/rxe/rxe_net.h
> @@ -17,6 +17,7 @@ struct rxe_recv_sockets {
>  };
>  
>  int rxe_net_add(const char *ibdev_name, struct net_device *ndev);
> +void rxe_net_del(struct ib_device *dev);
>  
>  int rxe_register_notifier(void);
>  int rxe_net_init(void);