vfio/fsl-mc: return -EFAULT if copy_to_user() fails

The copy_to_user() function returns the number of bytes remaining to be
copied, but this code should return -EFAULT.

Fixes: df747bc ("vfio/fsl-mc: Implement VFIO_DEVICE_GET_REGION_INFO ioctl call")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Diana Craciun <diana.craciun@oss.nxp.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Author: Dan Carpenter

drivers/vfio/fsl-mc/vfio_fsl_mc.c

@@ -248,7 +248,9 @@ static long vfio_fsl_mc_ioctl(void *device_data, unsigned int cmd,
 		info.size = vdev->regions[info.index].size;
 		info.flags = vdev->regions[info.index].flags;
 
-		return copy_to_user((void __user *)arg, &info, minsz);
+		if (copy_to_user((void __user *)arg, &info, minsz))
+			return -EFAULT;
+		return 0;
 	}
 	case VFIO_DEVICE_GET_IRQ_INFO:
 	{
@@ -267,7 +269,9 @@ static long vfio_fsl_mc_ioctl(void *device_data, unsigned int cmd,
 		info.flags = VFIO_IRQ_INFO_EVENTFD;
 		info.count = 1;
 
-		return copy_to_user((void __user *)arg, &info, minsz);
+		if (copy_to_user((void __user *)arg, &info, minsz))
+			return -EFAULT;
+		return 0;
 	}
 	case VFIO_DEVICE_SET_IRQS:
 	{