RDMA/qedr: Fix return code if accept is called on a destroyed qp

In iWARP, accept could be called after a QP is already destroyed.  In this
case an error should be returned and not success.

Fixes: 82af6d19d8 ("RDMA/qedr: Fix synchronization methods and memory leaks in qedr")
Link: https://lore.kernel.org/r/20200902165741.8355-5-michal.kalderon@marvell.com
Signed-off-by: Michal Kalderon <michal.kalderon@marvell.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/qedr/qedr_iw_cm.c

@@ -736,7 +736,7 @@ int qedr_iw_accept(struct iw_cm_id *cm_id, struct iw_cm_conn_param *conn_param)
 	struct qedr_dev *dev = ep->dev;
 	struct qedr_qp *qp;
 	struct qed_iwarp_accept_in params;
-	int rc = 0;
+	int rc;
 
 	DP_DEBUG(dev, QEDR_MSG_IWARP, "Accept on qpid=%d\n", conn_param->qpn);
 
@@ -759,8 +759,10 @@ int qedr_iw_accept(struct iw_cm_id *cm_id, struct iw_cm_conn_param *conn_param)
 	params.ord = conn_param->ord;
 
 	if (test_and_set_bit(QEDR_IWARP_CM_WAIT_FOR_CONNECT,
-			     &qp->iwarp_cm_flags))
+			     &qp->iwarp_cm_flags)) {
+		rc = -EINVAL;
 		goto err; /* QP already destroyed */
+	}
 
 	rc = dev->ops->iwarp_accept(dev->rdma_ctx, &params);
 	if (rc) {