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Commit f1ff6348 authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Steven Rostedt
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ftrace: Add separate function for non recursive callbacks 



Instead of using the generic list function for callbacks that
are not recursive, call a new helper function from the mcount
trampoline called ftrace_ops_recur_func() that will do the recursion
checking for the callback.

This eliminates an indirection as well as will help in future code
that will use dynamically allocated trampolines.

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 2ce7598c

kernel/trace/ftrace.c

+31 −2
Original line number Original line Diff line number Diff line
@@ -113,6 +113,9 @@ ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub; 
static struct ftrace_ops global_ops;

static struct ftrace_ops global_ops;

static struct ftrace_ops control_ops;

static struct ftrace_ops control_ops;





static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip,

				   struct ftrace_ops *op, struct pt_regs *regs);



#if ARCH_SUPPORTS_FTRACE_OPS

#if ARCH_SUPPORTS_FTRACE_OPS

static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,

static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,

				 struct ftrace_ops *op, struct pt_regs *regs);

				 struct ftrace_ops *op, struct pt_regs *regs);
@@ -258,11 +261,18 @@ static void update_ftrace_function(void) 
	if (ftrace_ops_list == &ftrace_list_end ||

	if (ftrace_ops_list == &ftrace_list_end ||

	    (ftrace_ops_list->next == &ftrace_list_end &&

	    (ftrace_ops_list->next == &ftrace_list_end &&

	     !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC) &&

	     !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC) &&

	     (ftrace_ops_list->flags & FTRACE_OPS_FL_RECURSION_SAFE) &&

	     !FTRACE_FORCE_LIST_FUNC)) {

	     !FTRACE_FORCE_LIST_FUNC)) {

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

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

		set_function_trace_op = ftrace_ops_list;

		set_function_trace_op = ftrace_ops_list;

		/*

		 * If the func handles its own recursion, call it directly.

		 * Otherwise call the recursion protected function that

		 * will call the ftrace ops function.

		 */

		if (ftrace_ops_list->flags & FTRACE_OPS_FL_RECURSION_SAFE)

			func = ftrace_ops_list->func;

			func = ftrace_ops_list->func;

		else

			func = ftrace_ops_recurs_func;

	} 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;
@@ -4827,6 +4837,25 @@ static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip) 
}

}

#endif

#endif





/*

 * If there's only one function registered but it does not support

 * recursion, this function will be called by the mcount trampoline.

 * This function will handle recursion protection.

 */

static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip,

				   struct ftrace_ops *op, struct pt_regs *regs)

{

	int bit;



	bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);

	if (bit < 0)

		return;



	op->func(ip, parent_ip, op, regs);



	trace_clear_recursion(bit);

}



static void clear_ftrace_swapper(void)

static void clear_ftrace_swapper(void)

{

{

	struct task_struct *p;

	struct task_struct *p;