On 2019-01-03 14:13, Janosch Frank wrote:
> On 03.01.19 13:58, Thomas Huth wrote:
>> On 2019-01-03 11:08, Janosch Frank wrote:
>>> We need to properly implement interrupt handling for SCLP, because on
>>> z/VM and LPAR SCLP calls are not synchronous!
>>>
>>> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> [...]
>>> +
>>> static void sclp_read_scp_info(ReadInfo *ri, int length)
>>> {
>>> unsigned int commands[] = { SCLP_CMDW_READ_SCP_INFO_FORCED,
>>> SCLP_CMDW_READ_SCP_INFO };
>>> - int i;
>>> + int i, cc;
>>>
>>> for (i = 0; i < ARRAY_SIZE(commands); i++) {
>>> memset(&ri->h, 0, sizeof(ri->h));
>>> ri->h.length = length;
>>>
>>> - if (sclp_service_call(commands[i], ri))
>>> + sclp_mark_busy();
>>> + cc = sclp_service_call(commands[i], ri);
>>> + sclp_wait_busy();
>>
>> You already do the sclp_wait_busy() in sclp_service_call now, so I think
>> you don't need the sclp_wait_busy() here anymore?
>
> Yeah, that has to go.
>
>>
>> Also, what about moving the sclp_mark_busy() calls to the beginning of
>> sclp_service_call() instead?
>
> Wouldn't that create a race on the data of __sccb and we could end with
> garbled scb commands?
Since there is a sclp_wait_busy in sclp_service_call already, you can be
sure that the previous command already finished, can't you?
Thomas
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