Re: [PATCH 08/18] pc-bios/s390-ccw: Remove panics from ECKD IPL path

[Thomas Huth <thuth@redhat.com>]

On 27/09/2024 02.51, jrossi@linux.ibm.com wrote:
> From: Jared Rossi <jrossi@linux.ibm.com>
> 
> Remove panic-on-error from ECKD block device IPL specific functions so that
> error recovery may be possible in the future.
> 
> Functions that would previously panic now provide a return code.
> 
> Signed-off-by: Jared Rossi <jrossi@linux.ibm.com>
> 
> ---
>   pc-bios/s390-ccw/bootmap.c | 183 +++++++++++++++++++++++++------------
>   1 file changed, 125 insertions(+), 58 deletions(-)
> 
> diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c
> index 0751a225cd..dc7200c264 100644
> --- a/pc-bios/s390-ccw/bootmap.c
> +++ b/pc-bios/s390-ccw/bootmap.c
> @@ -145,14 +145,17 @@ static block_number_t load_eckd_segments(block_number_t blk, bool ldipl,
>       bool more_data;
>   
>       memset(_bprs, FREE_SPACE_FILLER, sizeof(_bprs));
> -    read_block(blk, bprs, "BPRS read failed");
> +    if (virtio_read(blk, bprs)) {
> +        puts("BPRS read failed");
> +        return -EIO;
> +    }
>   
>       do {
>           more_data = false;
>           for (j = 0;; j++) {
>               block_nr = gen_eckd_block_num(&bprs[j].xeckd, ldipl);
>               if (is_null_block_number(block_nr)) { /* end of chunk */
> -                break;
> +                return 0; /* use 0 to indicate end of load, not real block 0 */

Can we be very sure that block 0 is never a valid one, so that returning 0 
is OK here? Maybe you could use an error code instead (intruducing e.g. 
ENOENT ?)

  Thomas