diff --git a/ChangeLog b/ChangeLog
index c4126756e0..3338ba7391 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Sat Dec 15 03:06:40 2012  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* file.c (rb_file_flock): use rb_thread_wait_for() instead of
+	  rb_thread_polling(). When getting EAGAIN, we need to wait a
+	  while even if no multi threading.
+	* thread.c (sleep_for_polling, rb_thread_polling) removed.
+
 Sat Dec 15 00:03:31 2012  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
 
 	* signal.c (rb_f_kill): remove rb_thread_polling() because this
diff --git a/file.c b/file.c
index 2aa896ae47..08cd5f8dcf 100644
--- a/file.c
+++ b/file.c
@@ -4200,6 +4200,7 @@ rb_file_flock(VALUE obj, VALUE operation)
 {
     rb_io_t *fptr;
     int op[2], op1;
+    struct timeval time;
 
     rb_secure(2);
     op[1] = op1 = NUM2INT(operation);
@@ -4217,7 +4218,10 @@ rb_file_flock(VALUE obj, VALUE operation)
 	  case EWOULDBLOCK:
 #endif
 	    if (op1 & LOCK_NB) return Qfalse;
-	    rb_thread_polling();
+
+	    time.tv_sec = 0;
+	    time.tv_usec = 100 * 1000;	/* 0.1 sec */
+	    rb_thread_wait_for(time);
 	    rb_io_check_closed(fptr);
 	    continue;
 
diff --git a/thread.c b/thread.c
index 4ea4c58f5d..56eddca895 100644
--- a/thread.c
+++ b/thread.c
@@ -994,15 +994,6 @@ sleep_wait_for_interrupt(rb_thread_t *th, double sleepsec,int spurious_check)
     sleep_timeval(th, double2timeval(sleepsec),spurious_check);
 }
 
-static void
-sleep_for_polling(rb_thread_t *th)
-{
-    struct timeval time;
-    time.tv_sec = 0;
-    time.tv_usec = 100 * 1000;	/* 0.1 sec */
-    sleep_timeval(th, time, 1);
-}
-
 void
 rb_thread_wait_for(struct timeval time)
 {
@@ -1010,16 +1001,6 @@ rb_thread_wait_for(struct timeval time)
     sleep_timeval(th, time, 1);
 }
 
-void
-rb_thread_polling(void)
-{
-    if (!rb_thread_alone()) {
-	rb_thread_t *th = GET_THREAD();
-	RUBY_VM_CHECK_INTS_BLOCKING(th);
-	sleep_for_polling(th);
-    }
-}
-
 /*
  * CAUTION: This function causes thread switching.
  *          rb_thread_check_ints() check ruby's interrupts.