ftrace: Consolidate updating of ftrace_trace_function
Steven Rostedt [Thu, 28 Apr 2011 01:43:36 +0000 (21:43 -0400)]
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>

kernel/trace/ftrace.c

index 5b758ea..33bcc71 100644 (file)
@@ -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