Commit 6e2fdcef authored by Steven Rostedt's avatar Steven Rostedt Committed by Steven Rostedt (Google)
Browse files

tracing: Use refcount for trace_event_file reference counter 

Instead of using an atomic counter for the trace_event_file reference
counter, use the refcount interface. It has various checks to make sure
the reference counting is correct, and will warn if it detects an error
(like refcount_inc() on '0').

Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20240726144208.687cce24@rorschach.local.home


Acked-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent b1560408

include/linux/trace_events.h

+1 −1
Original line number Diff line number Diff line
@@ -680,7 +680,7 @@ struct trace_event_file { 
	 * caching and such. Which is mostly OK ;-)

	 */

	unsigned long		flags;

	atomic_t		ref;	/* ref count for opened files */

	refcount_t		ref;	/* ref count for opened files */

	atomic_t		sm_ref;	/* soft-mode reference counter */

	atomic_t		tm_ref;	/* trigger-mode reference counter */

};

kernel/trace/trace_events.c

+4 −4
Original line number Diff line number Diff line
@@ -992,18 +992,18 @@ static void remove_subsystem(struct trace_subsystem_dir *dir) 


void event_file_get(struct trace_event_file *file)

{

	atomic_inc(&file->ref);

	refcount_inc(&file->ref);

}



void event_file_put(struct trace_event_file *file)

{

	if (WARN_ON_ONCE(!atomic_read(&file->ref))) {

	if (WARN_ON_ONCE(!refcount_read(&file->ref))) {

		if (file->flags & EVENT_FILE_FL_FREED)

			kmem_cache_free(file_cachep, file);

		return;

	}



	if (atomic_dec_and_test(&file->ref)) {

	if (refcount_dec_and_test(&file->ref)) {

		/* Count should only go to zero when it is freed */

		if (WARN_ON_ONCE(!(file->flags & EVENT_FILE_FL_FREED)))

			return;
@@ -3003,7 +3003,7 @@ trace_create_new_event(struct trace_event_call *call, 
	atomic_set(&file->tm_ref, 0);

	INIT_LIST_HEAD(&file->triggers);

	list_add(&file->list, &tr->events);

	event_file_get(file);

	refcount_set(&file->ref, 1);



	return file;

}