x86, ftrace: call trace->open() before stopping tracing; add trace->print_header()
Add a callback to allow an ftrace plug-in to write its own header.
Move the call to trace->open() up a few lines.
The changes are required by the BTS ftrace plug-in.
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index a45b59e..8df8fdd 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2298,7 +2298,9 @@
seq_printf(m, "# tracer: %s\n", iter->trace->name);
seq_puts(m, "#\n");
}
- if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
+ if (iter->trace && iter->trace->print_header)
+ iter->trace->print_header(m);
+ else if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
/* print nothing if the buffers are empty */
if (trace_empty(iter))
return 0;
@@ -2350,6 +2352,10 @@
iter->trace = current_trace;
iter->pos = -1;
+ /* Notify the tracer early; before we stop tracing. */
+ if (iter->trace && iter->trace->open)
+ iter->trace->open(iter);
+
/* Annotate start of buffers if we had overruns */
if (ring_buffer_overruns(iter->tr->buffer))
iter->iter_flags |= TRACE_FILE_ANNOTATE;
@@ -2375,9 +2381,6 @@
/* stop the trace while dumping */
tracing_stop();
- if (iter->trace && iter->trace->open)
- iter->trace->open(iter);
-
mutex_unlock(&trace_types_lock);
out: