From c7ba75697c258284d7e72dc2104307eb2c14ba91 Mon Sep 17 00:00:00 2001
From: YAMAMOTO Takashi <yamamoto@midokura.com>
Date: Wed, 30 Jun 2021 15:05:53 +0900
Subject: [PATCH] tcp_recvwindow.c: Use iob_tailroom to replace the home grown
 one

---
 net/tcp/tcp_recvwindow.c | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/net/tcp/tcp_recvwindow.c b/net/tcp/tcp_recvwindow.c
index fdb15691b1a..3f0e0b850aa 100644
--- a/net/tcp/tcp_recvwindow.c
+++ b/net/tcp/tcp_recvwindow.c
@@ -110,17 +110,7 @@ uint16_t tcp_get_recvwindow(FAR struct net_driver_s *dev,
 
   if (conn->readahead != NULL)
     {
-      /* XXX move this to mm/iob */
-
-      const struct iob_s *iob;
-
-      iob = conn->readahead;
-      while (iob->io_flink != NULL)
-        {
-          iob = iob->io_flink;
-        }
-
-      tailroom = CONFIG_IOB_BUFSIZE - (iob->io_offset + iob->io_len);
+      tailroom = iob_tailroom(conn->readahead);
     }
   else
     {