s390/cio: return -EFAULT if copy_to_user() fails again

commit 51c44babdc19aaf882e1213325a0ba291573308f 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: e01bcdd61320 ("vfio: ccw: realize VFIO_DEVICE_GET_REGION_INFO ioctl")
Signed-off-by: Wang Qing <wangqing@vivo.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/1614600093-13992-1-git-send-email-wangqing@vivo.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 560013c8d2a4843853ff6081a37285c6cbd5f2da..3222a6a450964fbed9beb880d372221613f2669a 100644 (file)
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -341,7 +341,7 @@ static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device *mdev,
                if (ret)
                        return ret;
 
-               return copy_to_user((void __user *)arg, &info, minsz);
+               return copy_to_user((void __user *)arg, &info, minsz) ? -EFAULT : 0;
        }
        case VFIO_DEVICE_GET_REGION_INFO:
        {
@@ -362,7 +362,7 @@ static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device *mdev,
                if (ret)
                        return ret;
 
-               return copy_to_user((void __user *)arg, &info, minsz);
+               return copy_to_user((void __user *)arg, &info, minsz) ? -EFAULT : 0;
        }
        case VFIO_DEVICE_GET_IRQ_INFO:
        {