RDMA/rxe: Use structs to describe the uABI instead of opencoding

Open coding pointer math is not acceptable for describing the uABI in
RDMA. Provide structs for all the cases.

The udata is casted to the struct as close to the verbs entry point
as possible for maximum clarity. Function signatures and so forth
are revised to allow for this.

Tested-by: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/sw/rxe/rxe_cq.c

@@ -83,7 +83,7 @@ static void rxe_send_complete(unsigned long data)
 
 int rxe_cq_from_init(struct rxe_dev *rxe, struct rxe_cq *cq, int cqe,
 		     int comp_vector, struct ib_ucontext *context,
-		     struct ib_udata *udata)
+		     struct rxe_create_cq_resp __user *uresp)
 {
 	int err;
 
@@ -94,15 +94,15 @@ int rxe_cq_from_init(struct rxe_dev *rxe, struct rxe_cq *cq, int cqe,
 		return -ENOMEM;
 	}
 
-	err = do_mmap_info(rxe, udata, false, context, cq->queue->buf,
-			   cq->queue->buf_size, &cq->queue->ip);
+	err = do_mmap_info(rxe, uresp ? &uresp->mi : NULL, context,
+			   cq->queue->buf, cq->queue->buf_size, &cq->queue->ip);
 	if (err) {
 		kvfree(cq->queue->buf);
 		kfree(cq->queue);
 		return err;
 	}
 
-	if (udata)
+	if (uresp)
 		cq->is_user = 1;
 
 	cq->is_dying = false;
@@ -114,14 +114,15 @@ int rxe_cq_from_init(struct rxe_dev *rxe, struct rxe_cq *cq, int cqe,
 	return 0;
 }
 
-int rxe_cq_resize_queue(struct rxe_cq *cq, int cqe, struct ib_udata *udata)
+int rxe_cq_resize_queue(struct rxe_cq *cq, int cqe,
+			struct rxe_resize_cq_resp __user *uresp)
 {
 	int err;
 
 	err = rxe_queue_resize(cq->queue, (unsigned int *)&cqe,
 			       sizeof(struct rxe_cqe),
 			       cq->queue->ip ? cq->queue->ip->context : NULL,
-			       udata, NULL, &cq->cq_lock);
+			       uresp ? &uresp->mi : NULL, NULL, &cq->cq_lock);
 	if (!err)
 		cq->ibcq.cqe = cqe;