Subject: Re: [PATCH rdma-next v2 7/7] RDMA/cma: Provide ECE reject reason

From: Jason Gunthorpe <[email-masked]>
Date: Mon, 25 May 2020 15:14:17 -0300

On Mon, Apr 13, 2020 at 05:15:38PM +0300, Leon Romanovsky wrote:
> @@ -4223,7 +4223,7 @@ int rdma_notify(struct rdma_cm_id *id, enum ib_event_type event)
>  EXPORT_SYMBOL(rdma_notify);
>  
>  int rdma_reject(struct rdma_cm_id *id, const void *private_data,
> -		u8 private_data_len)
> +		u8 private_data_len, enum rdma_ucm_reject_reason reason)
>  {
>  	struct rdma_id_private *id_priv;
>  	int ret;
> @@ -4237,10 +4237,12 @@ int rdma_reject(struct rdma_cm_id *id, const void *private_data,
>  			ret = cma_send_sidr_rep(id_priv, IB_SIDR_REJECT, 0,
>  						private_data, private_data_len);
>  		} else {
> +			enum ib_cm_rej_reason r =
> +				(reason) ?: IB_CM_REJ_CONSUMER_DEFINED;
> +
>  			trace_cm_send_rej(id_priv);
> -			ret = ib_send_cm_rej(id_priv->cm_id.ib,
> -					     IB_CM_REJ_CONSUMER_DEFINED, NULL,
> -					     0, private_data, private_data_len);
> +			ret = ib_send_cm_rej(id_priv->cm_id.ib, r, NULL, 0,
> +					     private_data, private_data_len);
>  		}
>  	} else if (rdma_cap_iw_cm(id->device, id->port_num)) {
>  		ret = iw_cm_reject(id_priv->cm_id.iw,
> diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
> index d41598954cc4..99482dc5934b 100644
> +++ b/drivers/infiniband/core/ucma.c
> @@ -1178,12 +1178,17 @@ static ssize_t ucma_reject(struct ucma_file *file, const char __user *inbuf,
>  	if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
>  		return -EFAULT;
>  
> +	if (cmd.reason &&
> +	    cmd.reason != RDMA_USER_CM_REJ_VENDOR_OPTION_NOT_SUPPORTED)
> +		return -EINVAL;

It would be clearer to set cmd.reason to IB_CM_REJ_CONSUMER_DEFINED at
this point.. 

if (!cmd.reason)
   cmd.reason = IB_CM_REJ_CONSUMER_DEFINED

if (cmd.reason != IB_CM_REJ_CONSUMER_DEFINED && cmd.reason !=
    RDMA_USER_CM_REJ_VENDOR_OPTION_NOT_SUPPORTED)
   return -EINVAL

Esaier to follow and no reason userspace shouldn't be able to
explicitly specifiy the reason's that it is allowed to use.

> index 8d961d8b7cdb..f8781b132f62 100644
> +++ b/include/rdma/rdma_cm.h
> @@ -324,11 +324,12 @@ int __rdma_accept_ece(struct rdma_cm_id *id, struct rdma_conn_param *conn_param,
>   */
>  int rdma_notify(struct rdma_cm_id *id, enum ib_event_type event);
>  
> +
>  /**

Extra hunk?

>   * rdma_reject - Called to reject a connection request or response.
>   */
>  int rdma_reject(struct rdma_cm_id *id, const void *private_data,
> -		u8 private_data_len);
> +		u8 private_data_len, enum rdma_ucm_reject_reason reason);
>  
>  /**
>   * rdma_disconnect - This function disconnects the associated QP and
> diff --git a/include/uapi/rdma/rdma_user_cm.h b/include/uapi/rdma/rdma_user_cm.h
> index c4ca1412bcf9..e545f2de1e13 100644
> +++ b/include/uapi/rdma/rdma_user_cm.h
> @@ -78,6 +78,10 @@ enum rdma_ucm_port_space {
>  	RDMA_PS_UDP   = 0x0111,
>  };
>  
> +enum rdma_ucm_reject_reason {
> +	RDMA_USER_CM_REJ_VENDOR_OPTION_NOT_SUPPORTED = 35
> +};

not sure we need ABI defines for IBTA constants?

Jason