s390/crypto: return -EFAULT if copy_to_user() fails

commit 942df4b upstream.

The copy_to_user() function returns the number of bytes remaining to be
copied, but we want to return -EFAULT if the copy doesn't complete.

Fixes: e06670c ("s390: vfio-ap: implement VFIO_DEVICE_GET_INFO ioctl")
Signed-off-by: Wang Qing <wangqing@vivo.com>
Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/1614600502-16714-1-git-send-email-wangqing@vivo.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/s390/crypto/vfio_ap_ops.c

@@ -1279,7 +1279,7 @@ static int vfio_ap_mdev_get_device_info(unsigned long arg)
 	info.num_regions = 0;
 	info.num_irqs = 0;
 
-	return copy_to_user((void __user *)arg, &info, minsz);
+	return copy_to_user((void __user *)arg, &info, minsz) ? -EFAULT : 0;
 }
 
 static ssize_t vfio_ap_mdev_ioctl(struct mdev_device *mdev,