mchan->req_buf_size = resource_size(&res);
                mchan->req_buf = devm_ioremap(mdev, res.start,
                                              mchan->req_buf_size);
-               if (IS_ERR(mchan->req_buf)) {
+               if (!mchan->req_buf) {
                        dev_err(mdev, "Unable to map IPI buffer I/O memory\n");
-                       ret = PTR_ERR(mchan->req_buf);
-                       return ret;
+                       return -ENOMEM;
                }
        } else if (ret != -ENODEV) {
                dev_err(mdev, "Unmatched resource %s, %d.\n", name, ret);
                mchan->resp_buf_size = resource_size(&res);
                mchan->resp_buf = devm_ioremap(mdev, res.start,
                                               mchan->resp_buf_size);
-               if (IS_ERR(mchan->resp_buf)) {
+               if (!mchan->resp_buf) {
                        dev_err(mdev, "Unable to map IPI buffer I/O memory\n");
-                       ret = PTR_ERR(mchan->resp_buf);
-                       return ret;
+                       return -ENOMEM;
                }
        } else if (ret != -ENODEV) {
                dev_err(mdev, "Unmatched resource %s.\n", name);
                mchan->req_buf_size = resource_size(&res);
                mchan->req_buf = devm_ioremap(mdev, res.start,
                                              mchan->req_buf_size);
-               if (IS_ERR(mchan->req_buf)) {
+               if (!mchan->req_buf) {
                        dev_err(mdev, "Unable to map IPI buffer I/O memory\n");
-                       ret = PTR_ERR(mchan->req_buf);
-                       return ret;
+                       return -ENOMEM;
                }
        } else if (ret != -ENODEV) {
                dev_err(mdev, "Unmatched resource %s.\n", name);
                mchan->resp_buf_size = resource_size(&res);
                mchan->resp_buf = devm_ioremap(mdev, res.start,
                                               mchan->resp_buf_size);
-               if (IS_ERR(mchan->resp_buf)) {
+               if (!mchan->resp_buf) {
                        dev_err(mdev, "Unable to map IPI buffer I/O memory\n");
-                       ret = PTR_ERR(mchan->resp_buf);
-                       return ret;
+                       return -ENOMEM;
                }
        } else if (ret != -ENODEV) {
                dev_err(mdev, "Unmatched resource %s.\n", name);