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Commit f7aad4e1 authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Steven Rostedt
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ftrace: Set callback to ftrace_stub when no ops are registered 



The clean up that adds the helper function ftrace_ops_get_func()
caused the default function to not change when DYNAMIC_FTRACE was not
set and no ftrace_ops were registered. Although static tracing is
not very useful (not having DYNAMIC_FTRACE set), it is still supported
and we don't want to break it.

Clean up the if statement even more to specifically have the default
function call ftrace_stub when no ftrace_ops are registered. This
fixes the small bug for static tracing as well as makes the code a
bit more understandable.

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 87354059

kernel/trace/ftrace.c

+13 −6
Original line number Original line Diff line number Diff line
@@ -253,18 +253,25 @@ static void update_ftrace_function(void) 
{

{

	ftrace_func_t func;

	ftrace_func_t func;





	/*

	 * Prepare the ftrace_ops that the arch callback will use.

	 * If there's only one ftrace_ops registered, the ftrace_ops_list

	 * will point to the ops we want.

	 */

	set_function_trace_op = ftrace_ops_list;



	/* If there's no ftrace_ops registered, just call the stub function */

	if (ftrace_ops_list == &ftrace_list_end) {

		func = ftrace_stub;



	/*

	/*

	 * If we are at the end of the list and this ops is

	 * If we are at the end of the list and this ops is

	 * recursion safe and not dynamic and the arch supports passing ops,

	 * recursion safe and not dynamic and the arch supports passing ops,

	 * then have the mcount trampoline call the function directly.

	 * then have the mcount trampoline call the function directly.

	 */

	 */

	if (ftrace_ops_list == &ftrace_list_end ||

	} else if (ftrace_ops_list->next == &ftrace_list_end) {

	    (ftrace_ops_list->next == &ftrace_list_end)) {



		/* Set the ftrace_ops that the arch callback uses */

		set_function_trace_op = ftrace_ops_list;



		func = ftrace_ops_get_func(ftrace_ops_list);

		func = ftrace_ops_get_func(ftrace_ops_list);



	} else {

	} else {

		/* Just use the default ftrace_ops */

		/* Just use the default ftrace_ops */

		set_function_trace_op = &ftrace_list_end;

		set_function_trace_op = &ftrace_list_end;