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Commit 491d0dcf authored by Steven Rostedt's avatar Steven Rostedt Committed by Steven Rostedt
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ftrace: Consolidate updating of ftrace_trace_function 



There are three locations that perform almost identical functions in order
to update the ftrace_trace_function (the ftrace function variable that gets
called by mcount).

Consolidate these into a single function called update_ftrace_function().

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 996e87be

kernel/trace/ftrace.c

+34 −61
Original line number Diff line number Diff line
@@ -151,34 +151,26 @@ static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip) 
}

#endif



static int __register_ftrace_function(struct ftrace_ops *ops)

static void update_ftrace_function(void)

{

	ops->next = ftrace_list;

	/*

	 * We are entering ops into the ftrace_list but another

	 * CPU might be walking that list. We need to make sure

	 * the ops->next pointer is valid before another CPU sees

	 * the ops pointer included into the ftrace_list.

	 */

	rcu_assign_pointer(ftrace_list, ops);



	if (ftrace_enabled) {

	ftrace_func_t func;



		if (ops->next == &ftrace_list_end)

			func = ops->func;

	/*

	 * If there's only one function registered, then call that

	 * function directly. Otherwise, we need to iterate over the

	 * registered callers.

	 */

	if (ftrace_list == &ftrace_list_end ||

	    ftrace_list->next == &ftrace_list_end)

		func = ftrace_list->func;

	else

		func = ftrace_list_func;



	/* If we filter on pids, update to use the pid function */

	if (!list_empty(&ftrace_pids)) {

		set_ftrace_pid_function(func);

		func = ftrace_pid_func;

	}



		/*

		 * For one func, simply call it directly.

		 * For more than one func, call the chain.

		 */

#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST

	ftrace_trace_function = func;

#else
@@ -187,6 +179,20 @@ static int __register_ftrace_function(struct ftrace_ops *ops) 
#endif

}



static int __register_ftrace_function(struct ftrace_ops *ops)

{

	ops->next = ftrace_list;

	/*

	 * We are entering ops into the ftrace_list but another

	 * CPU might be walking that list. We need to make sure

	 * the ops->next pointer is valid before another CPU sees

	 * the ops pointer included into the ftrace_list.

	 */

	rcu_assign_pointer(ftrace_list, ops);



	if (ftrace_enabled)

		update_ftrace_function();



	return 0;

}
@@ -213,52 +219,19 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops) 


	*p = (*p)->next;



	if (ftrace_enabled) {

		/* If we only have one func left, then call that directly */

		if (ftrace_list->next == &ftrace_list_end) {

			ftrace_func_t func = ftrace_list->func;



			if (!list_empty(&ftrace_pids)) {

				set_ftrace_pid_function(func);

				func = ftrace_pid_func;

			}

#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST

			ftrace_trace_function = func;

#else

			__ftrace_trace_function = func;

#endif

		}

	}

	if (ftrace_enabled)

		update_ftrace_function();



	return 0;

}



static void ftrace_update_pid_func(void)

{

	ftrace_func_t func;



	/* Only do something if we are tracing something */

	if (ftrace_trace_function == ftrace_stub)

		return;



#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST

	func = ftrace_trace_function;

#else

	func = __ftrace_trace_function;

#endif



	if (!list_empty(&ftrace_pids)) {

		set_ftrace_pid_function(func);

		func = ftrace_pid_func;

	} else {

		if (func == ftrace_pid_func)

			func = ftrace_pid_function;

	}



#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST

	ftrace_trace_function = func;

#else

	__ftrace_trace_function = func;

#endif

	update_ftrace_function();

}



#ifdef CONFIG_FUNCTION_PROFILER