Re: [Qemu-devel] [PATCH 3/4] s390x/css: remove dubious error handling branch

[Halil Pasic <pasic@linux.vnet.ibm.com>]

On 09/11/2017 11:48 AM, Cornelia Huck wrote:
> On Fri,  8 Sep 2017 17:24:45 +0200
> Halil Pasic <pasic@linux.vnet.ibm.com> wrote:
> 
> s/dubious/unused/
> 

Nod.

>> The case in question actually never happens. Let us get rid of the dead
>> code.
> 
> I had tried to be complete in my initial implementation. With the
> current implementation, it can never happen, yes. We can easily
> resurrect it from git history should we need it in the future.
> 

I've tried to understand the branch but I failed. Weather the subchannel
is busy or not should be already decided, and if the device is busy
that is probably supposed to be indicated via device status (word 2 bit 3).

So I wrote dubious because I could not figure it out. But unused
is certainly nicer.

I think shall the need emerge the preferred way of handling would
be to use the custom handling (-EIO) branch.


>>
>> Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
>> ---
>>  hw/s390x/css.c | 7 -------
>>  1 file changed, 7 deletions(-)
>>
>> diff --git a/hw/s390x/css.c b/hw/s390x/css.c
>> index a44d87ab3e..a9cdd54efc 100644
>> --- a/hw/s390x/css.c
>> +++ b/hw/s390x/css.c
>> @@ -980,13 +980,6 @@ static void sch_handle_start_func_virtual(SubchDev *sch)
>>                      SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;
>>              s->cpa = sch->channel_prog + 8;
>>              break;
>> -        case -EBUSY:
>> -            /* subchannel busy, generate deferred cc 1 */
>> -            s->flags &= ~SCSW_FLAGS_MASK_CC;
>> -            s->flags |= (1 << 8);
>> -            s->ctrl &= ~SCSW_CTRL_MASK_STCTL;
>> -            s->ctrl |= SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;
>> -            break;
>>          case -EINPROGRESS:
>>              /* channel program has been suspended */
>>              s->ctrl &= ~SCSW_ACTL_START_PEND;
> 
> Thanks, queued.
> 

Thanks!