Re: [PATCH for-5.2 3/6] pc-bios/s390-ccw: Move the inner logic of find_subch() to a separate function

[Cornelia Huck]

On Tue, 28 Jul 2020 20:37:31 +0200
Thomas Huth <thuth@redhat.com> wrote:

> Move the code to a separate function to be able to re-use it from a
> different spot later.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  pc-bios/s390-ccw/main.c | 99 ++++++++++++++++++++++++-----------------
>  1 file changed, 57 insertions(+), 42 deletions(-)
> 
> diff --git a/pc-bios/s390-ccw/main.c b/pc-bios/s390-ccw/main.c
> index 9b64eb0c24..9477313188 100644
> --- a/pc-bios/s390-ccw/main.c
> +++ b/pc-bios/s390-ccw/main.c
> @@ -51,6 +51,60 @@ unsigned int get_loadparm_index(void)
>      return atoui(loadparm_str);
>  }
>  
> +static int check_sch_no(int dev_no, int sch_no)

check_subchannel()? You verify dev_no as well, if supplied.

> +{
> +    bool is_virtio;
> +    Schib schib;
> +    int r;
> +
> +    blk_schid.sch_no = sch_no;
> +    r = stsch_err(blk_schid, &schib);
> +    if (r == 3 || r == -EIO) {
> +        return -EIO;

-ENODEV? It means that you either have no devices, or an invalid
subchannel set.

> +    }
> +    if (!schib.pmcw.dnv) {
> +        return false;
> +    }
> +
> +    enable_subchannel(blk_schid);
> +    cutype = cu_type(blk_schid);
> +
> +    /*
> +     * Note: we always have to run virtio_is_supported() here to make
> +     * sure that the vdev.senseid data gets pre-initialized correctly
> +     */
> +    is_virtio = virtio_is_supported(blk_schid);
> +
> +    /* No specific devno given, just return 1st possibly bootable device */

"just return whether the device is possibly bootable" ?

> +    if (dev_no < 0) {
> +        switch (cutype) {
> +        case CU_TYPE_VIRTIO:
> +            if (is_virtio) {
> +                /*
> +                 * Skip net devices since no IPLB is created and therefore
> +                 * no network bootloader has been loaded
> +                 */
> +                if (virtio_get_device_type() != VIRTIO_ID_NET) {
> +                    return true;
> +                }
> +            }
> +            return false;
> +        case CU_TYPE_DASD_3990:
> +        case CU_TYPE_DASD_2107:
> +            return true;
> +        default:
> +            return false;
> +        }
> +    }
> +
> +    /* Caller asked for a specific devno */
> +    if (schib.pmcw.dev == dev_no) {
> +        return true;
> +    }
> +
> +    return false;
> +}
> +
>  /*
>   * Find the subchannel connected to the given device (dev_no) and fill in the
>   * subchannel information block (schib) with the connected subchannel's info.
 (...)

Otherwise, LGTM.