[PATCH 4/5] tracing: Delete timestamp_mode trace file

[sunliming]

The timestamp_mode trace file is not necessary duo to the removing of
the absolute timestamp.

Signed-off-by: sunliming <sunliming@xxxxxxxxxx>
---
 Documentation/trace/ftrace.rst | 24 ------------------
 kernel/trace/trace.c           | 45 ----------------------------------
 2 files changed, 69 deletions(-)

diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst
index 60bceb018d6a..9b4a4e9c1cbd 100644
--- a/Documentation/trace/ftrace.rst
+++ b/Documentation/trace/ftrace.rst
@@ -615,30 +615,6 @@ of ftrace. Here is a list of some of the key files:
 
 	See events.rst for more information.
 
-  timestamp_mode:
-
-	Certain tracers may change the timestamp mode used when
-	logging trace events into the event buffer.  Events with
-	different modes can coexist within a buffer but the mode in
-	effect when an event is logged determines which timestamp mode
-	is used for that event.  The default timestamp mode is
-	'delta'.
-
-	Usual timestamp modes for tracing:
-
-	  # cat timestamp_mode
-	  [delta] absolute
-
-	  The timestamp mode with the square brackets around it is the
-	  one in effect.
-
-	  delta: Default timestamp mode - timestamp is a delta against
-	         a per-buffer timestamp.
-
-	  absolute: The timestamp is a full timestamp, not a delta
-                 against some other value.  As such it takes up more
-                 space and is less efficient.
-
   hwlat_detector:
 
 	Directory for the Hardware Latency Detector.
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 47a44b055a1d..af8cbcad0bad 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5494,9 +5494,6 @@ static const char readme_msg[] =
 #ifdef CONFIG_X86_64
 	"     x86-tsc:   TSC cycle counter\n"
 #endif
-	"\n  timestamp_mode\t- view the mode used to timestamp events\n"
-	"       delta:   Delta difference against a buffer-wide timestamp\n"
-	"    absolute:   Absolute (standalone) timestamp\n"
 	"\n  trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
 	"\n  trace_marker_raw\t\t- Writes into this file writes binary data into the kernel buffer\n"
 	"  tracing_cpumask\t- Limit which CPUs to trace\n"
@@ -7319,38 +7316,6 @@ static int tracing_clock_open(struct inode *inode, struct file *file)
 	return ret;
 }
 
-static int tracing_time_stamp_mode_show(struct seq_file *m, void *v)
-{
-	struct trace_array *tr = m->private;
-
-	mutex_lock(&trace_types_lock);
-
-	if (ring_buffer_time_stamp_abs(tr->array_buffer.buffer))
-		seq_puts(m, "delta [absolute]\n");
-	else
-		seq_puts(m, "[delta] absolute\n");
-
-	mutex_unlock(&trace_types_lock);
-
-	return 0;
-}
-
-static int tracing_time_stamp_mode_open(struct inode *inode, struct file *file)
-{
-	struct trace_array *tr = inode->i_private;
-	int ret;
-
-	ret = tracing_check_open_get_tr(tr);
-	if (ret)
-		return ret;
-
-	ret = single_open(file, tracing_time_stamp_mode_show, inode->i_private);
-	if (ret < 0)
-		trace_array_put(tr);
-
-	return ret;
-}
-
 u64 tracing_event_time_stamp(struct trace_buffer *buffer, struct ring_buffer_event *rbe)
 {
 	if (rbe == this_cpu_read(trace_buffered_event))
@@ -7643,13 +7608,6 @@ static const struct file_operations trace_clock_fops = {
 	.write		= tracing_clock_write,
 };
 
-static const struct file_operations trace_time_stamp_mode_fops = {
-	.open		= tracing_time_stamp_mode_open,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= tracing_single_release_tr,
-};
-
 #ifdef CONFIG_TRACER_SNAPSHOT
 static const struct file_operations snapshot_fops = {
 	.open		= tracing_snapshot_open,
@@ -9580,9 +9538,6 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
 	trace_create_file("tracing_on", TRACE_MODE_WRITE, d_tracer,
 			  tr, &rb_simple_fops);
 
-	trace_create_file("timestamp_mode", TRACE_MODE_READ, d_tracer, tr,
-			  &trace_time_stamp_mode_fops);
-
 	tr->buffer_percent = 50;
 
 	trace_create_file("buffer_percent", TRACE_MODE_READ, d_tracer,
-- 
2.25.1