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Commit 8bba1bf5 authored by Markus Metzger's avatar Markus Metzger Committed by Ingo Molnar
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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: default avatarMarkus Metzger <markus.t.metzger@intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 6abb11ae

kernel/trace/trace.c

+7 −4
Original line number Diff line number Diff line
@@ -2298,7 +2298,9 @@ static int s_show(struct seq_file *m, void *v) 
			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 @@ __tracing_open(struct inode *inode, struct file *file, int *ret) 
	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 @@ __tracing_open(struct inode *inode, struct file *file, int *ret) 
	/* stop the trace while dumping */

	tracing_stop();



	if (iter->trace && iter->trace->open)

			iter->trace->open(iter);



	mutex_unlock(&trace_types_lock);



 out:

kernel/trace/trace.h

+1 −0
Original line number Diff line number Diff line
@@ -311,6 +311,7 @@ struct tracer { 
	int			(*selftest)(struct tracer *trace,

					    struct trace_array *tr);

#endif

	void			(*print_header)(struct seq_file *m);

	enum print_line_t	(*print_line)(struct trace_iterator *iter);

	/* If you handled the flag setting, return 0 */

	int			(*set_flag)(u32 old_flags, u32 bit, int set);