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>

1 files changed, 15 insertions, 34 deletions

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 56c260b83a9c..6f03c8a1105e 100644
--- 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;
         }