Re: [PATCH for-rc] RDMA/core: Fix corrupted SL on passive side

[Jason Gunthorpe <jgg@nvidia.com>]

On Mon, Mar 22, 2021 at 02:35:32PM +0100, Håkon Bugge wrote:
> On RoCE systems, a CM REQ contains a Primary Hop Limit > 1 and Primary
> Subnet Local is zero.
> 
> In cm_req_handler(), the cm_process_routed_req() function is
> called. Since the Primary Subnet Local value is zero in the request,
> and since this is RoCE (Primary Local LID is permissive), the
> following statement will be executed:
> 
>       IBA_SET(CM_REQ_PRIMARY_SL, req_msg, wc->sl);
> 
> This corrupts SL in req_msg if it was different from zero. In other
> words, a request to setup a connection using an SL != zero, will not
> be honored, and a connection using SL zero will be created instead.
> 
> Fixed by not calling cm_process_routed_req() on RoCE systems.
> 
> Fixes: 3971c9f6dbf2 ("IB/cm: Add interim support for routed paths")
> Signed-off-by: Håkon Bugge <haakon.bugge@oracle.com>
>  drivers/infiniband/core/cm.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
> index 3d194bb..6adbaea 100644
> +++ b/drivers/infiniband/core/cm.c
> @@ -2138,7 +2138,8 @@ static int cm_req_handler(struct cm_work *work)
>  		goto destroy;
>  	}
>  
> -	cm_process_routed_req(req_msg, work->mad_recv_wc->wc);
> +	if (cm_id_priv->av.ah_attr.type != RDMA_AH_ATTR_TYPE_ROCE)
> +		cm_process_routed_req(req_msg, work->mad_recv_wc->wc);

why use ah_attr.type when a few lines below we have:

	if (gid_attr &&
	    rdma_protocol_roce(work->port->cm_dev->ib_device,
			       work->port->port_num)) {

?

I suspect you can just move this into the else?

Jason