On 2/14/20 7:11 AM, Cornelia Huck wrote:
> On Thu, 6 Feb 2020 22:38:18 +0100
> Eric Farman <farman@xxxxxxxxxxxxx> wrote:
>
>> From: Farhan Ali <alifm@xxxxxxxxxxxxx>
>>
>> Register the chp_event callback to receive channel path related
>> events for the subchannels managed by vfio-ccw.
>
> I'm wondering how useful this patch would be on its own.
Probably not much. I can't speak to his original thoughts on the
matter, but it doesn't seem to buy us much by itself other than a
consumable sized patch.
>
>>
>> Signed-off-by: Farhan Ali <alifm@xxxxxxxxxxxxx>
>> Signed-off-by: Eric Farman <farman@xxxxxxxxxxxxx>
>> ---
>>
>> Notes:
>> v1->v2:
>> - Move s390dbf before cio_update_schib() call [CH]
>>
>> v0->v1: [EF]
>> - Add s390dbf trace
>>
>> drivers/s390/cio/vfio_ccw_drv.c | 44 +++++++++++++++++++++++++++++++++
>> 1 file changed, 44 insertions(+)
>>
> (...)
>> @@ -257,6 +258,48 @@ static int vfio_ccw_sch_event(struct subchannel *sch, int process)
>> return rc;
>> }
>>
>> +static int vfio_ccw_chp_event(struct subchannel *sch,
>> + struct chp_link *link, int event)
>> +{
>> + struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
>> + int mask = chp_ssd_get_mask(&sch->ssd_info, link);
>> + int retry = 255;
>> +
>> + if (!private || !mask)
>> + return 0;
>> +
>> + VFIO_CCW_MSG_EVENT(2, "%pUl (%x.%x.%04x): mask=0x%x event=%d\n",
>> + mdev_uuid(private->mdev), sch->schid.cssid,
>> + sch->schid.ssid, sch->schid.sch_no,
>> + mask, event);
>> +
>> + if (cio_update_schib(sch))
>> + return -ENODEV;
>> +
>> + switch (event) {
>> + case CHP_VARY_OFF:
>> + /* Path logically turned off */
>> + sch->opm &= ~mask;
>> + sch->lpm &= ~mask;
>> + break;
>> + case CHP_OFFLINE:
>> + /* Path is gone */
>> + cio_cancel_halt_clear(sch, &retry);
>
> Any reason you do this only for CHP_OFFLINE and not for CHP_VARY_OFF?
Hrm... No reason that I can think of. I can fix this.
>
>> + break;
>> + case CHP_VARY_ON:
>> + /* Path logically turned on */
>> + sch->opm |= mask;
>> + sch->lpm |= mask;
>> + break;
>> + case CHP_ONLINE:
>> + /* Path became available */
>> + sch->lpm |= mask & sch->opm;
>
> If I'm not mistaken, this patch introduces the first usage of sch->opm
> in the vfio-ccw code.
Correct.
> Are we missing something?
Maybe? :)
>Or am I missing
> something? :)
>
Since it's only used in this code, for acting as a step between
vary/config off/on, maybe this only needs to be dealing with the lpm
field itself?
>> + break;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> static struct css_device_id vfio_ccw_sch_ids[] = {
>> { .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
>> { /* end of list */ },
> (...)
>
