RDMA/siw: Properly check send and receive CQ pointers

The check for the NULL of pointer received from container_of() is
incorrect by definition as it points to some offset from NULL.

Change such check with proper NULL check of SIW QP attributes.

Fixes: 303ae1cd ("rdma/siw: application interface")
Link: https://lore.kernel.org/r/a7535a82925f6f4c1f062abaa294f3ae6e54bdd2.1620560310.git.leonro@nvidia.comSigned-off-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Bernard Metzler <bmt@zurich.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/sw/siw/siw_verbs.c

@@ -300,7 +300,6 @@ struct ib_qp *siw_create_qp(struct ib_pd *pd,
 	struct siw_ucontext *uctx =
 		rdma_udata_to_drv_context(udata, struct siw_ucontext,
 					  base_ucontext);
-	struct siw_cq *scq = NULL, *rcq = NULL;
 	unsigned long flags;
 	int num_sqe, num_rqe, rv = 0;
 	size_t length;
@@ -343,10 +342,8 @@ struct ib_qp *siw_create_qp(struct ib_pd *pd,
 		rv = -EINVAL;
 		goto err_out;
 	}
-	scq = to_siw_cq(attrs->send_cq);
-	rcq = to_siw_cq(attrs->recv_cq);
 
-	if (!scq || (!rcq && !attrs->srq)) {
+	if (!attrs->send_cq || (!attrs->recv_cq && !attrs->srq)) {
 		siw_dbg(base_dev, "send CQ or receive CQ invalid\n");
 		rv = -EINVAL;
 		goto err_out;
@@ -401,8 +398,8 @@ struct ib_qp *siw_create_qp(struct ib_pd *pd,
 		}
 	}
 	qp->pd = pd;
-	qp->scq = scq;
-	qp->rcq = rcq;
+	qp->scq = to_siw_cq(attrs->send_cq);
+	qp->rcq = to_siw_cq(attrs->recv_cq);
 
 	if (attrs->srq) {
 		/*