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

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

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)
> +{
> +    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;
> +    }
> +    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 */
> +    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;
> +                }

here it seems you are returning true for any non-network virtio device,
is this the intended behaviour? (I know it was like this in the old
code)

like, non-block devices?

> +            }
> +            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. @@ -62,53 +116,14 @@ unsigned int
> get_loadparm_index(void) */
>  static bool find_subch(int dev_no)
>  {
> -    Schib schib;
>      int i, r;
> -    bool is_virtio;
>  
>      for (i = 0; i < 0x10000; i++) {
> -        blk_schid.sch_no = i;
> -        r = stsch_err(blk_schid, &schib);
> -        if ((r == 3) || (r == -EIO)) {
> +        r = check_sch_no(dev_no, i);
> +        if (r < 0) {
>              break;
>          }
> -        if (!schib.pmcw.dnv) {
> -            continue;
> -        }
> -
> -        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 */
> -        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;
> -                    }
> -                }
> -                continue;
> -            case CU_TYPE_DASD_3990:
> -            case CU_TYPE_DASD_2107:
> -                return true;
> -            default:
> -                continue;
> -            }
> -        }
> -
> -        /* Caller asked for a specific devno */
> -        if (schib.pmcw.dev == dev_no) {
> +        if (r == true) {
>              return true;
>          }
>      }