usb: usbtmc: Add ioctl USBTMC_IOCTL_CLEANUP_IO

The ioctl USBTMC_IOCTL_CLEANUP_IO kills all submitted urbs to OUT
and IN bulk, and clears all received data from IN bulk. Internal
transfer counters and error states are reset.

An application should use this ioctl after an asnychronous transfer
was canceled and/or error handling has finished.
Signed-off-by: Guido Kiener <guido.kiener@rohde-schwarz.com>
Reviewed-by: Steve Bayless <steve_bayless@keysight.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/class/usbtmc.c

@@ -1706,6 +1706,21 @@ static int usbtmc_ioctl_cancel_io(struct usbtmc_file_data *file_data)
 	return 0;
 }
 
+static int usbtmc_ioctl_cleanup_io(struct usbtmc_file_data *file_data)
+{
+	usb_kill_anchored_urbs(&file_data->submitted);
+	usb_scuttle_anchored_urbs(&file_data->in_anchor);
+	spin_lock_irq(&file_data->err_lock);
+	file_data->in_status = 0;
+	file_data->in_transfer_size = 0;
+	file_data->out_status = 0;
+	file_data->out_transfer_size = 0;
+	spin_unlock_irq(&file_data->err_lock);
+
+	file_data->in_urbs_used = 0;
+	return 0;
+}
+
 static int get_capabilities(struct usbtmc_device_data *data)
 {
 	struct device *dev = &data->usb_dev->dev;
@@ -2130,6 +2145,10 @@ static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	case USBTMC_IOCTL_CANCEL_IO:
 		retval = usbtmc_ioctl_cancel_io(file_data);
 		break;
+
+	case USBTMC_IOCTL_CLEANUP_IO:
+		retval = usbtmc_ioctl_cleanup_io(file_data);
+		break;
 	}
 
 skip_io_on_zombie:

include/uapi/linux/usb/tmc.h

@@ -99,6 +99,7 @@ struct usbtmc_message {
 
 /* Cancel and cleanup asynchronous calls */
 #define USBTMC_IOCTL_CANCEL_IO		_IO(USBTMC_IOC_NR, 35)
+#define USBTMC_IOCTL_CLEANUP_IO		_IO(USBTMC_IOC_NR, 36)
 
 /* Driver encoded usb488 capabilities */
 #define USBTMC488_CAPABILITY_TRIGGER         1