tracing/events: use list_for_entry_continue

Simplify s_next() and t_next().

Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4AB32389.1030005@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 56c260b83a9cc8a4fa76a44a387cbc68691ae2ff..6f03c8a1105e925f7604b7aaeac21e6486cb7c4f 100644 (file)
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -271,42 +271,32 @@ ftrace_event_write(struct file *file, const char __user *ubuf,
 static void *
 t_next(struct seq_file *m, void *v, loff_t *pos)
 {
-       struct list_head *list = m->private;
-       struct ftrace_event_call *call;
+       struct ftrace_event_call *call = v;
 
        (*pos)++;
 
-       for (;;) {
-               if (list == &ftrace_events)
-                       return NULL;
-
-               call = list_entry(list, struct ftrace_event_call, list);
-
+       list_for_each_entry_continue(call, &ftrace_events, list) {
                /*
                 * The ftrace subsystem is for showing formats only.
                 * They can not be enabled or disabled via the event files.
                 */
                if (call->regfunc)
-                       break;
-
-               list = list->next;
+                       return call;
        }
 
-       m->private = list->next;
-
-       return call;
+       return NULL;
 }
 
 static void *t_start(struct seq_file *m, loff_t *pos)
 {
-       struct ftrace_event_call *call = NULL;
+       struct ftrace_event_call *call;
        loff_t l;
 
        mutex_lock(&event_mutex);
 
-       m->private = ftrace_events.next;
+       call = list_entry(&ftrace_events, struct ftrace_event_call, list);
        for (l = 0; l <= *pos; ) {
-               call = t_next(m, NULL, &l);
+               call = t_next(m, call, &l);
                if (!call)
                        break;
        }
@@ -316,37 +306,28 @@ static void *t_start(struct seq_file *m, loff_t *pos)
 static void *
 s_next(struct seq_file *m, void *v, loff_t *pos)
 {
-       struct list_head *list = m->private;
-       struct ftrace_event_call *call;
+       struct ftrace_event_call *call = v;
 
        (*pos)++;
 
- retry:
-       if (list == &ftrace_events)
-               return NULL;
-
-       call = list_entry(list, struct ftrace_event_call, list);
-
-       if (!call->enabled) {
-               list = list->next;
-               goto retry;
+       list_for_each_entry_continue(call, &ftrace_events, list) {
+               if (call->enabled)
+                       return call;
        }
 
-       m->private = list->next;
-
-       return call;
+       return NULL;
 }
 
 static void *s_start(struct seq_file *m, loff_t *pos)
 {
-       struct ftrace_event_call *call = NULL;
+       struct ftrace_event_call *call;
        loff_t l;
 
        mutex_lock(&event_mutex);
 
-       m->private = ftrace_events.next;
+       call = list_entry(&ftrace_events, struct ftrace_event_call, list);
        for (l = 0; l <= *pos; ) {
-               call = s_next(m, NULL, &l);
+               call = s_next(m, call, &l);
                if (!call)
                        break;
        }