[PATCH v3 5/5] tracing: Free up file->private_data for use by individual events

[Petr Pavlu <petr.pavlu@suse.com>]

The tracing_open_file_tr() function currently copies the trace_event_file
pointer from inode->i_private to file->private_data when the file is
successfully opened. This duplication is not particularly useful, as all
event code should utilize event_file_file() or event_file_data() to
retrieve a trace_event_file pointer from a file struct and these access
functions read file->f_inode->i_private. Moreover, this setup requires the
code for opening hist files to explicitly clear file->private_data before
calling single_open(), since this function expects the private_data member
to be set to NULL and uses it to store a pointer to a seq_file.

Remove the unnecessary setting of file->private_data in
tracing_open_file_tr() and simplify the hist code.

Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
---
 kernel/trace/trace.c             | 2 --
 kernel/trace/trace_events_hist.c | 4 ----
 2 files changed, 6 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2f6fbf9e7caf..a51c675be0f4 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4051,8 +4051,6 @@ int tracing_open_file_tr(struct inode *inode, struct file *filp)
 		event_file_get(file);
 	}
 
-	filp->private_data = inode->i_private;
-
 	return 0;
 }
 
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 768df987419e..57c76d40be2d 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -5837,8 +5837,6 @@ static int event_hist_open(struct inode *inode, struct file *file)
 	hist_file->file = file;
 	hist_file->last_act = get_hist_hit_count(event_file);
 
-	/* Clear private_data to avoid warning in single_open() */
-	file->private_data = NULL;
 	ret = single_open(file, hist_show, hist_file);
 	if (ret) {
 		kfree(hist_file);
@@ -6127,8 +6125,6 @@ static int event_hist_debug_open(struct inode *inode, struct file *file)
 	if (ret)
 		return ret;
 
-	/* Clear private_data to avoid warning in single_open() */
-	file->private_data = NULL;
 	ret = single_open(file, hist_debug_show, file);
 	if (ret)
 		tracing_release_file_tr(inode, file);
-- 
2.53.0