diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index 7132f3d50c50..5ad49dfd0c23 100644
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -485,6 +485,7 @@ static int usbtmc488_ioctl_read_stb(struct usbtmc_file_data *file_data,
 	u8 tag;
 	__u8 stb;
 	int rv;
+	long wait_rv;
 
 	dev_dbg(dev, "Enter ioctl_read_stb iin_ep_present: %d\n",
 		data->iin_ep_present);
@@ -527,16 +528,17 @@ static int usbtmc488_ioctl_read_stb(struct usbtmc_file_data *file_data,
 	}
 
 	if (data->iin_ep_present) {
-		rv = wait_event_interruptible_timeout(
+		wait_rv = wait_event_interruptible_timeout(
 			data->waitq,
 			atomic_read(&data->iin_data_valid) != 0,
 			file_data->timeout);
-		if (rv < 0) {
-			dev_dbg(dev, "wait interrupted %d\n", rv);
+		if (wait_rv < 0) {
+			dev_dbg(dev, "wait interrupted %ld\n", wait_rv);
+			rv = wait_rv;
 			goto exit;
 		}
 
-		if (rv == 0) {
+		if (wait_rv == 0) {
 			dev_dbg(dev, "wait timed out\n");
 			rv = -ETIMEDOUT;
 			goto exit;
@@ -556,6 +558,8 @@ static int usbtmc488_ioctl_read_stb(struct usbtmc_file_data *file_data,
 	rv = put_user(stb, (__u8 __user *)arg);
 	dev_dbg(dev, "stb:0x%02x received %d\n", (unsigned int)stb, rv);
 
+	rv = 0;
+
  exit:
 	/* bump interrupt bTag */
 	data->iin_bTag += 1;