vfio-ccw: Trace the FSM jumptable

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@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Message-Id: <20191016142040.14132-3-farman@linux.ibm.com>
Acked-by: Halil Pasic <pasic@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
index bbe9babf767b8abd48920799b5b5053b0ab9af8a..9b9bb4982972a20902ff1d736874bea8a7c41db5 100644 (file)
--- 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 d5cc943c68642293196e6ed5862f2ef43fcda2b8..b37bc68e7f1858b4cface8ae804d30bc40a88bb9 100644 (file)
--- 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 2a2937a40124c9708a131a064e12f9f0274e37b0..5005d57901b4ecb2bd76d217451787b801596860 100644 (file)
--- 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=%d event=%d",
+               __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),