Re: [PATCH v2] RDMA/vmw_pvrdma: Use resource ids from physical device if available

[Jason Gunthorpe <jgg@ziepe.ca>]

On Mon, Oct 28, 2019 at 04:46:09PM +0000, Adit Ranadive wrote:
> On 10/28/19 9:27 AM, Jason Gunthorpe wrote:
> > On Tue, Oct 22, 2019 at 08:06:50PM +0000, Adit Ranadive wrote:
> >> @@ -195,7 +198,9 @@ struct ib_qp *pvrdma_create_qp(struct ib_pd *pd,
> >>  	union pvrdma_cmd_resp rsp;
> >>  	struct pvrdma_cmd_create_qp *cmd = &req.create_qp;
> >>  	struct pvrdma_cmd_create_qp_resp *resp = &rsp.create_qp_resp;
> >> +	struct pvrdma_cmd_create_qp_resp_v2 *resp_v2 = &rsp.create_qp_resp_v2;
> >>  	struct pvrdma_create_qp ucmd;
> >> +	struct pvrdma_create_qp_resp qp_resp = {};
> >>  	unsigned long flags;
> >>  	int ret;
> >>  	bool is_srq = !!init_attr->srq;
> >> @@ -260,6 +265,15 @@ struct ib_qp *pvrdma_create_qp(struct ib_pd *pd,
> >>  				goto err_qp;
> >>  			}
> >>  
> >> +			/* Userspace supports qpn and qp handles? */
> >> +			if (dev->dsr_version >= PVRDMA_QPHANDLE_VERSION &&
> >> +			    udata->outlen != sizeof(qp_resp)) {
> > 
> > Is != really what you want? Or is <= better? != means you can't ever
> > make qp_resp bigger.
> 
> I thought about using != or < before sending the patch. Since we removed
> the flag anyways using != here made sense to be more strict about what's
> acceptable. I'm not sure if we'll ever make it bigger.

It is a big gamble you will never need to add new entries to this
struct forever more. Better to be safe, IMHO.

Jason