diff --git a/ChangeLog b/ChangeLog
index 4d27c38ca1..86f9db71f3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Thu Sep 25 19:37:34 2014  Eric Wong  <e@80x24.org>
+
+	* io.c (free_io_buffer): new function for a common pattern
+	  (clear_readconv): use free_io_buffer
+	  (rb_io_fptr_finalize): ditto
+
 Thu Sep 25 07:51:07 2014  Ayumu AIZAWA  <ayumu.aizawa@gmail.com>
 
 	* lib/matrix.rb: Fix docs. Patched by Ben Woodall. [GH-726]
diff --git a/io.c b/io.c
index 5909a0be50..876ae675a4 100644
--- a/io.c
+++ b/io.c
@@ -4325,6 +4325,15 @@ rb_io_fptr_cleanup(rb_io_t *fptr, int noraise)
     }
 }
 
+static void
+free_io_buffer(rb_io_buffer_t *buf)
+{
+    if (buf->ptr) {
+        ruby_sized_xfree(buf->ptr, (size_t)buf->capa);
+        buf->ptr = NULL;
+    }
+}
+
 static void
 clear_readconv(rb_io_t *fptr)
 {
@@ -4332,10 +4341,7 @@ clear_readconv(rb_io_t *fptr)
         rb_econv_close(fptr->readconv);
         fptr->readconv = NULL;
     }
-    if (fptr->cbuf.ptr) {
-        free(fptr->cbuf.ptr);
-        fptr->cbuf.ptr = NULL;
-    }
+    free_io_buffer(&fptr->cbuf);
 }
 
 static void
@@ -4363,14 +4369,8 @@ rb_io_fptr_finalize(rb_io_t *fptr)
     if (0 <= fptr->fd)
 	rb_io_fptr_cleanup(fptr, TRUE);
     fptr->write_lock = 0;
-    if (fptr->rbuf.ptr) {
-        free(fptr->rbuf.ptr);
-        fptr->rbuf.ptr = 0;
-    }
-    if (fptr->wbuf.ptr) {
-        free(fptr->wbuf.ptr);
-        fptr->wbuf.ptr = 0;
-    }
+    free_io_buffer(&fptr->rbuf);
+    free_io_buffer(&fptr->wbuf);
     clear_codeconv(fptr);
     free(fptr);
     return 1;