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-rw-r--r--kernel/trace/trace.c11
-rw-r--r--kernel/trace/trace.h1
2 files changed, 8 insertions, 4 deletions
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);