From: Markus Metzger <markus.t.metzger@intel.com>
Date: Tue, 25 Nov 2008 08:12:31 +0000 (+0100)
Subject: x86, ftrace: call trace->open() before stopping tracing; add trace->print_header()
X-Git-Tag: v2.6.29-rc1~586^2~45
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=8bba1bf5e2434c83f2fe8b1422604ace9bbe4cb8;p=linux-2.6-omap-h63xx.git

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 a45b59e53fb..8df8fdd69c9 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -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:
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 28c15c2ebc2..717f9f045c6 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -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);