[ 020/149] usb: gadgetfs: return number of bytes on ep0 read request

3.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Thomas Faber <redacted>

commit 85b4b3c8c189e0159101f7628a71411af072ff69 upstream.

A read from GadgetFS endpoint 0 during the data stage of a control
request would always return 0 on success (as returned by
wait_event_interruptible) despite having written data into the user
buffer.
This patch makes it correctly set the return value to the number of
bytes read.

Signed-off-by: Thomas Faber <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/gadget/inode.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/usb/gadget/inode.c
+++ b/drivers/usb/gadget/inode.c

@@ -1043,6 +1043,8 @@ ep0_read (struct file *fd, char __user *
 // FIXME don't call this with the spinlock held ...
 				if (copy_to_user (buf, dev->req->buf, len))
 					retval = -EFAULT;
+				else
+					retval = len;
 				clean_req (dev->gadget->ep0, dev->req);
 				/* NOTE userspace can't yet choose to stall */
 			}