USB: simplify the interface of usb_get_status()

This patch simplifies the interface presented by usb_get_status().
Instead of forcing callers to check for the proper data length and
convert the status value to host byte order, the function will now
do these things itself.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/core/hub.c

@@ -1464,11 +1464,10 @@ static int hub_configure(struct usb_hub *hub,
 	 * and battery-powered root hubs (may provide just 8 mA).
 	 */
 	ret = usb_get_status(hdev, USB_RECIP_DEVICE, 0, &hubstatus);
-	if (ret < 2) {
+	if (ret) {
 		message = "can't get hub status";
 		goto fail;
 	}
-	le16_to_cpus(&hubstatus);
 	hcd = bus_to_hcd(hdev->bus);
 	if (hdev == hdev->bus->root_hub) {
 		if (hcd->power_budget > 0)
@@ -3101,8 +3100,6 @@ static int finish_port_resume(struct usb_device *udev)
 	if (status == 0) {
 		devstatus = 0;
 		status = usb_get_status(udev, USB_RECIP_DEVICE, 0, &devstatus);
-		if (status >= 0)
-			status = (status > 0 ? 0 : -ENODEV);
 
 		/* If a normal resume failed, try doing a reset-resume */
 		if (status && !udev->reset_resume && udev->persist_enabled) {
@@ -3123,7 +3120,6 @@ static int finish_port_resume(struct usb_device *udev)
 	 */
 	} else if (udev->actconfig && !udev->reset_resume) {
 		if (!hub_is_superspeed(udev->parent)) {
-			le16_to_cpus(&devstatus);
 			if (devstatus & (1 << USB_DEVICE_REMOTE_WAKEUP))
 				status = usb_control_msg(udev,
 						usb_sndctrlpipe(udev, 0),
@@ -3135,7 +3131,6 @@ static int finish_port_resume(struct usb_device *udev)
 		} else {
 			status = usb_get_status(udev, USB_RECIP_INTERFACE, 0,
 					&devstatus);
-			le16_to_cpus(&devstatus);
 			if (!status && devstatus & (USB_INTRF_STAT_FUNC_RW_CAP
 					| USB_INTRF_STAT_FUNC_RW))
 				status =
@@ -4481,11 +4476,10 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
 
 			status = usb_get_status(udev, USB_RECIP_DEVICE, 0,
 					&devstat);
-			if (status < 2) {
+			if (status) {
 				dev_dbg(&udev->dev, "get status %d ?\n", status);
 				goto loop_disable;
 			}
-			le16_to_cpus(&devstat);
 			if ((devstat & (1 << USB_DEVICE_SELF_POWERED)) == 0) {
 				dev_err(&udev->dev,
 					"can't connect bus-powered hub "

drivers/usb/core/message.c

@@ -934,13 +934,13 @@ int usb_get_device_descriptor(struct usb_device *dev, unsigned int size)
  *
  * This call is synchronous, and may not be used in an interrupt context.
  *
- * Returns the number of bytes received on success, or else the status code
- * returned by the underlying usb_control_msg() call.
+ * Returns 0 and the status value in *@data (in host byte order) on success,
+ * or else the status code from the underlying usb_control_msg() call.
  */
 int usb_get_status(struct usb_device *dev, int type, int target, void *data)
 {
 	int ret;
-	u16 *status = kmalloc(sizeof(*status), GFP_KERNEL);
+	__le16 *status = kmalloc(sizeof(*status), GFP_KERNEL);
 
 	if (!status)
 		return -ENOMEM;
@@ -949,7 +949,12 @@ int usb_get_status(struct usb_device *dev, int type, int target, void *data)
 		USB_REQ_GET_STATUS, USB_DIR_IN | type, 0, target, status,
 		sizeof(*status), USB_CTRL_GET_TIMEOUT);
 
-	*(u16 *)data = *status;
+	if (ret == 2) {
+		*(u16 *) data = le16_to_cpu(*status);
+		ret = 0;
+	} else if (ret >= 0) {
+		ret = -EIO;
+	}
 	kfree(status);
 	return ret;
 }

drivers/usb/misc/usbtest.c

@@ -747,9 +747,9 @@ static int ch9_postconfig(struct usbtest_dev *dev)
 
 	/* [9.4.5] get_status always works */
 	retval = usb_get_status(udev, USB_RECIP_DEVICE, 0, dev->buf);
-	if (retval != 2) {
+	if (retval) {
 		dev_err(&iface->dev, "get dev status --> %d\n", retval);
-		return (retval < 0) ? retval : -EDOM;
+		return retval;
 	}
 
 	/* FIXME configuration.bmAttributes says if we could try to set/clear
@@ -758,9 +758,9 @@ static int ch9_postconfig(struct usbtest_dev *dev)
 
 	retval = usb_get_status(udev, USB_RECIP_INTERFACE,
 			iface->altsetting[0].desc.bInterfaceNumber, dev->buf);
-	if (retval != 2) {
+	if (retval) {
 		dev_err(&iface->dev, "get interface status --> %d\n", retval);
-		return (retval < 0) ? retval : -EDOM;
+		return retval;
 	}
 	/* FIXME get status for each endpoint in the interface */
 
@@ -1351,7 +1351,6 @@ static int verify_halted(struct usbtest_dev *tdev, int ep, struct urb *urb)
 				ep, retval);
 		return retval;
 	}
-	le16_to_cpus(&status);
 	if (status != 1) {
 		ERROR(tdev, "ep %02x bogus status: %04x != 1\n", ep, status);
 		return -EINVAL;