[for-next][PATCH 04/19] tracing: Save the last hist commands associated event name

Steven Rostedt
2019-04-04T01:38:07Z

From: Tom Zanussi <tom.zanussi@linux.intel.com>

In preparation for making use of the new trace 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.

Link: http://lkml.kernel.org/r/eb0fd1362be8f39facb86c83eecf441b7a5876f8.1554072478.git.tom.zanussi@linux.intel.com

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/trace/trace_events_hist.c | 33 ++++++++++++++++++++++++++------
1 file changed, 27 insertions(+), 6 deletions(-)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 795aa2038377..0de702bf148f 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -535,15 +535,34 @@ static struct track_data *track_data_alloc(unsigned int key_len,
return data;
}

-static char last_hist_cmd[MAX_FILTER_STR_VAL];
+static char last_cmd[MAX_FILTER_STR_VAL];
+static char last_cmd_loc[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);
+ strncpy(last_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_cmd_loc, MAX_FILTER_STR_VAL, "hist:%s:%s", system, name);
}

static void hist_err(char *str, char *var)
@@ -583,6 +602,8 @@ 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_cmd[0] = '\0';
+ last_cmd_loc[0] = '\0';
}

static bool have_hist_err(void)
@@ -5438,8 +5459,8 @@ static int hist_show(struct seq_file *m, void *v)
}

if (have_hist_err()) {
- seq_printf(m, "\nERROR: %s\n", hist_err_str);
- seq_printf(m, " Last command: %s\n", last_hist_cmd);
+ seq_printf(m, "\n%s: error: \n", hist_err_str);
+ seq_printf(m, " Last command: %s\n", last_cmd);
}

out_unlock:
@@ -6043,8 +6064,8 @@ static int event_hist_trigger_func(struct event_command *cmd_ops,
lockdep_assert_held(&event_mutex);

if (glob && strlen(glob)) {
- last_cmd_set(param);
hist_err_clear();
+ last_cmd_set(file, param);
}

if (!param)
--
2.20.1