On 10/15/19 6:01 AM, Steffen Maier wrote:
> On 10/14/19 8:08 PM, Eric Farman wrote:
>> It would be nice if we could track the sequence of events within
>> vfio-ccw, based on the state of the device/FSM and our calling
>> sequence within it. So let's add a simple trace here so we can
>> watch the states change as things go, and allow it to be folded
>> into the rest of the other cio traces.
>>
>> Signed-off-by: Eric Farman <farman@xxxxxxxxxxxxx>
>> ---
>> drivers/s390/cio/vfio_ccw_private.h | 1 +
>> drivers/s390/cio/vfio_ccw_trace.c | 1 +
>> drivers/s390/cio/vfio_ccw_trace.h | 26 ++++++++++++++++++++++++++
>> 3 files changed, 28 insertions(+)
>>
>> diff --git a/drivers/s390/cio/vfio_ccw_private.h
>> b/drivers/s390/cio/vfio_ccw_private.h
>> index bbe9babf767b..9b9bb4982972 100644
>> --- a/drivers/s390/cio/vfio_ccw_private.h
>> +++ b/drivers/s390/cio/vfio_ccw_private.h
>> @@ -135,6 +135,7 @@ extern fsm_func_t
>> *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS];
>> static inline void vfio_ccw_fsm_event(struct vfio_ccw_private *private,
>> int event)
>> {
>> + trace_vfio_ccw_fsm_event(private->sch->schid, private->state,
>> event);
>> vfio_ccw_jumptable[private->state][event](private, event);
>> }
>>
>> diff --git a/drivers/s390/cio/vfio_ccw_trace.c
>> b/drivers/s390/cio/vfio_ccw_trace.c
>> index d5cc943c6864..b37bc68e7f18 100644
>> --- a/drivers/s390/cio/vfio_ccw_trace.c
>> +++ b/drivers/s390/cio/vfio_ccw_trace.c
>> @@ -9,4 +9,5 @@
>> #define CREATE_TRACE_POINTS
>> #include "vfio_ccw_trace.h"
>>
>> +EXPORT_TRACEPOINT_SYMBOL(vfio_ccw_fsm_event);
>> EXPORT_TRACEPOINT_SYMBOL(vfio_ccw_io_fctl);
>> diff --git a/drivers/s390/cio/vfio_ccw_trace.h
>> b/drivers/s390/cio/vfio_ccw_trace.h
>> index 2a2937a40124..24a8152acfdf 100644
>> --- a/drivers/s390/cio/vfio_ccw_trace.h
>> +++ b/drivers/s390/cio/vfio_ccw_trace.h
>> @@ -17,6 +17,32 @@
>>
>> #include <linux/tracepoint.h>
>>
>> +TRACE_EVENT(vfio_ccw_fsm_event,
>> + TP_PROTO(struct subchannel_id schid, int state, int event),
>> + TP_ARGS(schid, state, event),
>> +
>> + TP_STRUCT__entry(
>> + __field(u8, cssid)
>> + __field(u8, ssid)
>> + __field(u16, schno)
>> + __field(int, state)
>> + __field(int, event)
>> + ),
>> +
>> + TP_fast_assign(
>> + __entry->cssid = schid.cssid;
>> + __entry->ssid = schid.ssid;
>> + __entry->schno = schid.sch_no;
>> + __entry->state = state;
>> + __entry->event = event;
>> + ),
>> +
>> + TP_printk("schid=%x.%x.%04x state=%x event=%x",
>
> /sys/kernel/debug/tracing/events](0)# grep -R '%[^%]*x'
>
> Many existing TPs often seem to format hex output with a 0x prefix
> (either explicit with 0x%x or implicit with %#x). Since some of your
> other TPs also output decimal integer values, I wonder if a distinction
> would help unexperienced TP readers.
Fair enough. Since they're just enumerated values, they are probably
better as %d; I don't have a good reason for picking %x (with or without
a preceding 0x).
>
>> + __entry->cssid, __entry->ssid, __entry->schno,
>> + __entry->state,
>> + __entry->event)
>> +);
>> +
>> TRACE_EVENT(vfio_ccw_io_fctl,
>> TP_PROTO(int fctl, struct subchannel_id schid, int errno, char
>> *errstr),
>> TP_ARGS(fctl, schid, errno, errstr),
>>
>
>
