Commit a943188d authored by Eric Vaughn's avatar Eric Vaughn Committed by Steven Rostedt (Google)
Browse files

tracing/user_events: Optimize safe list traversals 

Several of the list traversals in the user_events facility use safe list
traversals where they could be using the unsafe versions instead.

Replace these safe traversals with their unsafe counterparts in the
interest of optimization.

Link: https://lore.kernel.org/linux-trace-kernel/20230810194337.695983-1-ervaughn@linux.microsoft.com



Suggested-by: default avatarBeau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: default avatarEric Vaughn <ervaughn@linux.microsoft.com>
Acked-by: default avatarBeau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent c8f05f2f

kernel/trace/trace_events_user.c

+8 −7
Original line number Diff line number Diff line
@@ -1328,14 +1328,14 @@ static int user_field_set_string(struct ftrace_event_field *field, 


static int user_event_set_print_fmt(struct user_event *user, char *buf, int len)

{

	struct ftrace_event_field *field, *next;

	struct ftrace_event_field *field;

	struct list_head *head = &user->fields;

	int pos = 0, depth = 0;

	const char *str_func;



	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");



	list_for_each_entry_safe_reverse(field, next, head, link) {

	list_for_each_entry_reverse(field, head, link) {

		if (depth != 0)

			pos += snprintf(buf + pos, LEN_OR_ZERO, " ");
@@ -1347,7 +1347,7 @@ static int user_event_set_print_fmt(struct user_event *user, char *buf, int len) 


	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");



	list_for_each_entry_safe_reverse(field, next, head, link) {

	list_for_each_entry_reverse(field, head, link) {

		if (user_field_is_dyn_string(field->type, &str_func))

			pos += snprintf(buf + pos, LEN_OR_ZERO,

					", %s(%s)", str_func, field->name);
@@ -1732,7 +1732,7 @@ static int user_event_create(const char *raw_command) 
static int user_event_show(struct seq_file *m, struct dyn_event *ev)

{

	struct user_event *user = container_of(ev, struct user_event, devent);

	struct ftrace_event_field *field, *next;

	struct ftrace_event_field *field;

	struct list_head *head;

	int depth = 0;
@@ -1740,7 +1740,7 @@ static int user_event_show(struct seq_file *m, struct dyn_event *ev) 


	head = trace_get_fields(&user->call);



	list_for_each_entry_safe_reverse(field, next, head, link) {

	list_for_each_entry_reverse(field, head, link) {

		if (depth == 0)

			seq_puts(m, " ");

		else
@@ -1816,13 +1816,14 @@ static bool user_field_match(struct ftrace_event_field *field, int argc, 
static bool user_fields_match(struct user_event *user, int argc,

			      const char **argv)

{

	struct ftrace_event_field *field, *next;

	struct ftrace_event_field *field;

	struct list_head *head = &user->fields;

	int i = 0;



	list_for_each_entry_safe_reverse(field, next, head, link)

	list_for_each_entry_reverse(field, head, link) {

		if (!user_field_match(field, argc, argv, &i))

			return false;

	}



	if (i != argc)

		return false;