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: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 34 insertions, 61 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 5b758ea344c..33bcc71ca09 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -151,6 +151,34 @@ static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
 }
 #endif
 
+static void update_ftrace_function(void)
+{
+        ftrace_func_t 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;
+        }
+#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
+        ftrace_trace_function = func;
+#else
+        __ftrace_trace_function = func;
+        ftrace_trace_function = ftrace_test_stop_func;
+#endif
+}
+
 static int __register_ftrace_function(struct ftrace_ops *ops)
 {
         ops->next = ftrace_list;
@@ -162,30 +190,8 @@ static int __register_ftrace_function(struct ftrace_ops *ops)
          */
         rcu_assign_pointer(ftrace_list, ops);
 
-        if (ftrace_enabled) {
-                ftrace_func_t func;
-
-                if (ops->next == &ftrace_list_end)
-                        func = ops->func;
-                else
-                        func = ftrace_list_func;
-
-                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
-                __ftrace_trace_function = func;
-                ftrace_trace_function = ftrace_test_stop_func;
-#endif
-        }
+        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