diff --git a/ChangeLog b/ChangeLog
index 0d4d59540e..94bc0c8d0d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Mon Apr 11 21:51:52 2011  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* io.c: revert r31230.
+
 Mon Apr 11 21:49:18 2011  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
 
 	* test/ruby/test_io.rb: Added TestIO#test_cross_thread_close_stdio
diff --git a/io.c b/io.c
index 7ce7148627..46845eb58b 100644
--- a/io.c
+++ b/io.c
@@ -3490,45 +3490,6 @@ finish_writeconv_sync(VALUE arg)
     return finish_writeconv(p->fptr, p->noalloc);
 }
 
-static VALUE
-nogvl_close(void *ptr)
-{
-    int *fd = ptr;
-
-    return (VALUE)close(*fd);
-}
-
-static int
-maygvl_close(int fd, int keepgvl)
-{
-    if (keepgvl)
-	return close(fd);
-
-    /*
-     * close() may block for certain file types (NFS, SO_LINGER sockets,
-     * inotify), so let other threads run.
-     */
-    return (int)rb_thread_blocking_region(nogvl_close, &fd, RUBY_UBF_IO, 0);
-}
-
-static VALUE
-nogvl_fclose(void *ptr)
-{
-    FILE *file = ptr;
-
-    return (VALUE)fclose(file);
-}
-
-static int
-maygvl_fclose(FILE *file, int keepgvl)
-{
-    if (keepgvl)
-	return fclose(file);
-
-    return (int)rb_thread_blocking_region(nogvl_fclose, file, RUBY_UBF_IO, 0);
-}
-
-
 static void
 fptr_finalize(rb_io_t *fptr, int noraise)
 {
@@ -3560,15 +3521,15 @@ fptr_finalize(rb_io_t *fptr, int noraise)
     if (fptr->stdio_file) {
         /* fptr->stdio_file is deallocated anyway
          * even if fclose failed.  */
-	if ((maygvl_fclose(fptr->stdio_file, noraise) < 0) && NIL_P(err))
+        if (fclose(fptr->stdio_file) < 0 && NIL_P(err))
             err = noraise ? Qtrue : INT2NUM(errno);
     }
     else if (0 <= fptr->fd) {
         /* fptr->fd may be closed even if close fails.
          * POSIX doesn't specify it.
          * We assumes it is closed.  */
-	if ((maygvl_close(fptr->fd, noraise) < 0) && NIL_P(err))
-	    err = noraise ? Qtrue : INT2NUM(errno);
+        if (close(fptr->fd) < 0 && NIL_P(err))
+            err = noraise ? Qtrue : INT2NUM(errno);
     }
   skip_fd_close:
     fptr->fd = -1;
@@ -5824,7 +5785,7 @@ io_reopen(VALUE io, VALUE nfile)
 		rb_sys_fail_path(orig->pathv);
 	}
 	else {
-	    maygvl_fclose(fptr->stdio_file, 0);
+            fclose(fptr->stdio_file);
             fptr->stdio_file = 0;
             fptr->fd = -1;
             if (dup2(fd2, fd) < 0)