[PATCH 1/3] trace-cmd: Move kernel_stack event handler to "function" plugin.

["Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>]

The "kernel_stack" event handler does not depend on any trace-cmd
context, it can be used aside from the application. The code is
moved to libtraceevent "function" plugin.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 lib/trace-cmd/trace-ftrace.c | 52 ------------------------------------
 plugins/plugin_function.c    | 41 ++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 52 deletions(-)

diff --git a/lib/trace-cmd/trace-ftrace.c b/lib/trace-cmd/trace-ftrace.c
index ed68099..22e5213 100644
--- a/lib/trace-cmd/trace-ftrace.c
+++ b/lib/trace-cmd/trace-ftrace.c
@@ -31,17 +31,6 @@ struct tep_plugin_option trace_ftrace_options[] = {
 static struct tep_plugin_option *fgraph_tail = &trace_ftrace_options[0];
 static struct tep_plugin_option *fgraph_depth = &trace_ftrace_options[1];
 
-static void find_long_size(struct tracecmd_ftrace *finfo)
-{
-	finfo->long_size = tracecmd_long_size(finfo->handle);
-}
-
-#define long_size_check(handle)				\
-	do {						\
-		if (!finfo->long_size)				\
-			find_long_size(finfo);		\
-	} while (0)
-
 static int find_ret_event(struct tracecmd_ftrace *finfo, struct tep_handle *pevent)
 {
 	struct tep_event *event;
@@ -361,44 +350,6 @@ fgraph_ret_handler(struct trace_seq *s, struct tep_record *record,
 	return 0;
 }
 
-static int
-trace_stack_handler(struct trace_seq *s, struct tep_record *record,
-		    struct tep_event *event, void *context)
-{
-	struct tracecmd_ftrace *finfo = context;
-	struct tep_format_field *field;
-	unsigned long long addr;
-	const char *func;
-	void *data = record->data;
-
-	field = tep_find_any_field(event, "caller");
-	if (!field) {
-		trace_seq_printf(s, "<CANT FIND FIELD %s>", "caller");
-		return 0;
-	}
-
-	trace_seq_puts(s, "<stack trace>\n");
-
-	long_size_check(finfo);
-
-	for (data += field->offset; data < record->data + record->size;
-	     data += finfo->long_size) {
-		addr = tep_read_number(event->tep, data, finfo->long_size);
-
-		if ((finfo->long_size == 8 && addr == (unsigned long long)-1) ||
-		    ((int)addr == -1))
-			break;
-
-		func = tep_find_function(event->tep, addr);
-		if (func)
-			trace_seq_printf(s, "=> %s (%llx)\n", func, addr);
-		else
-			trace_seq_printf(s, "=> %llx\n", addr);
-	}
-
-	return 0;
-}
-
 /**
  * tracecmd_ftrace_load_options - load the ftrace options
  *
@@ -430,9 +381,6 @@ int tracecmd_ftrace_overrides(struct tracecmd_input *handle,
 	tep_register_event_handler(pevent, -1, "ftrace", "funcgraph_exit",
 				      fgraph_ret_handler, finfo);
 
-	tep_register_event_handler(pevent, -1, "ftrace", "kernel_stack",
-				      trace_stack_handler, finfo);
-
 	trace_util_add_options("ftrace", trace_ftrace_options);
 
 	/* Store the func ret id and event for later use */
diff --git a/plugins/plugin_function.c b/plugins/plugin_function.c
index 91beb74..21ee531 100644
--- a/plugins/plugin_function.c
+++ b/plugins/plugin_function.c
@@ -169,11 +169,52 @@ static int function_handler(struct trace_seq *s, struct tep_record *record,
 	return 0;
 }
 
+static int
+trace_stack_handler(struct trace_seq *s, struct tep_record *record,
+		    struct tep_event *event, void *context)
+{
+	struct tep_format_field *field;
+	unsigned long long addr;
+	const char *func;
+	int long_size;
+	void *data = record->data;
+
+	field = tep_find_any_field(event, "caller");
+	if (!field) {
+		trace_seq_printf(s, "<CANT FIND FIELD %s>", "caller");
+		return 0;
+	}
+
+	trace_seq_puts(s, "<stack trace >\n");
+
+	long_size = tep_get_long_size(event->tep);
+
+	for (data += field->offset; data < record->data + record->size;
+	     data += long_size) {
+		addr = tep_read_number(event->tep, data, long_size);
+
+		if ((long_size == 8 && addr == (unsigned long long)-1) ||
+		    ((int)addr == -1))
+			break;
+
+		func = tep_find_function(event->tep, addr);
+		if (func)
+			trace_seq_printf(s, "=> %s (%llx)\n", func, addr);
+		else
+			trace_seq_printf(s, "=> %llx\n", addr);
+	}
+
+	return 0;
+}
+
 int TEP_PLUGIN_LOADER(struct tep_handle *tep)
 {
 	tep_register_event_handler(tep, -1, "ftrace", "function",
 				   function_handler, NULL);
 
+	tep_register_event_handler(tep, -1, "ftrace", "kernel_stack",
+				      trace_stack_handler, NULL);
+
 	trace_util_add_options("ftrace", plugin_options);
 
 	return 0;
-- 
2.21.0