[RFC PATCH 3/4] vfio-ccw: Add a trace for asynchronous requests

Eric Farman
2019-10-14T18:09:06Z

Since the asynchronous requests are typically associated with
error recovery, let's add a simple trace when one of those is
issued to a device.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
---
drivers/s390/cio/vfio_ccw_fsm.c | 4 ++++
drivers/s390/cio/vfio_ccw_trace.c | 1 +
drivers/s390/cio/vfio_ccw_trace.h | 26 ++++++++++++++++++++++++++
3 files changed, 31 insertions(+)

diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c
index d4119e4c4a8c..23648a9aa721 100644
--- a/drivers/s390/cio/vfio_ccw_fsm.c
+++ b/drivers/s390/cio/vfio_ccw_fsm.c
@@ -341,6 +341,10 @@ static void fsm_async_request(struct vfio_ccw_private *private,
/* should not happen? */
cmd_region->ret_code = -EINVAL;
}
+
+ trace_vfio_ccw_fsm_async_request(get_schid(private),
+ cmd_region->command,
+ cmd_region->ret_code);
}

/*
diff --git a/drivers/s390/cio/vfio_ccw_trace.c b/drivers/s390/cio/vfio_ccw_trace.c
index b37bc68e7f18..37ecbf8be805 100644
--- a/drivers/s390/cio/vfio_ccw_trace.c
+++ b/drivers/s390/cio/vfio_ccw_trace.c
@@ -9,5 +9,6 @@
#define CREATE_TRACE_POINTS
#include "vfio_ccw_trace.h"

+EXPORT_TRACEPOINT_SYMBOL(vfio_ccw_fsm_async_request);
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 24a8152acfdf..4be2e36242e6 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_async_request,
+ TP_PROTO(struct subchannel_id schid,
+ int command,
+ int errno),
+ TP_ARGS(schid, command, errno),
+
+ TP_STRUCT__entry(
+ __field_struct(struct subchannel_id, schid)
+ __field(int, command)
+ __field(int, errno)
+ ),
+
+ TP_fast_assign(
+ __entry->schid = schid;
+ __entry->command = command;
+ __entry->errno = errno;
+ ),
+
+ TP_printk("schid=%x.%x.%04x command=%d errno=%d",
+ __entry->schid.cssid,
+ __entry->schid.ssid,
+ __entry->schid.sch_no,
+ __entry->command,
+ __entry->errno)
+);
+
TRACE_EVENT(vfio_ccw_fsm_event,
TP_PROTO(struct subchannel_id schid, int state, int event),
TP_ARGS(schid, state, event),
--
2.17.1