[PATCH 3/6] tracing: Save the last hist command's associated event name

[Tom Zanussi]

In preparation for making use of the new trace event error log, save
the subsystem and event name associated with the last hist command -
it will be passed as the location param in the event_log_err() calls.

Signed-off-by: Tom Zanussi <tom.zanu...@linux.intel.com>
---
 kernel/trace/trace_events_hist.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 66c87be..4a42df4 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -354,14 +354,32 @@ struct action_data {
 
 
 static char last_hist_cmd[MAX_FILTER_STR_VAL];
+static char last_hist_cmd_event[MAX_FILTER_STR_VAL];
 static char hist_err_str[MAX_FILTER_STR_VAL];
 
-static void last_cmd_set(char *str)
+static void last_cmd_set(struct trace_event_file *file, char *str)
 {
+       const char *system = NULL, *name = NULL;
+       struct trace_event_call *call;
+
        if (!str)
                return;
 
        strncpy(last_hist_cmd, str, MAX_FILTER_STR_VAL - 1);
+
+       if (file) {
+               call = file->event_call;
+
+               system = call->class->system;
+               if (system) {
+                       name = trace_event_name(call);
+                       if (!name)
+                               system = NULL;
+               }
+       }
+
+       if (system)
+               snprintf(last_hist_cmd_event, MAX_FILTER_STR_VAL, "%s:%s", 
system, name);
 }
 
 static void hist_err(char *str, char *var)
@@ -401,6 +419,8 @@ static void hist_err_event(char *str, char *system, char 
*event, char *var)
 static void hist_err_clear(void)
 {
        hist_err_str[0] = '\0';
+       last_hist_cmd[0] = '\0';
+       last_hist_cmd_event[0] = '\0';
 }
 
 static bool have_hist_err(void)
@@ -5478,8 +5498,8 @@ static int event_hist_trigger_func(struct event_command 
*cmd_ops,
        int ret = 0;
 
        if (glob && strlen(glob)) {
-               last_cmd_set(param);
                hist_err_clear();
+               last_cmd_set(file, param);
        }
 
        if (!param)
-- 
1.9.3