1 files changed, 9 insertions, 1 deletions

diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index ddeef41049ae..eca3e094031a 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -1887,8 +1887,16 @@ static int qeth_ulp_enable_cb(struct qeth_card *card, struct qeth_reply *reply,
                         QETH_DBF_TEXT_(SETUP, 2, "  rc%d", iob->rc);
                         return 0;
                 }
-                card->info.max_mtu = mtu;
+                if (card->info.initial_mtu && (card->info.initial_mtu != mtu)) {
+                        /* frame size has changed */
+                        if (card->dev &&
+                            ((card->dev->mtu == card->info.initial_mtu) ||
+                             (card->dev->mtu > mtu)))
+                                card->dev->mtu = mtu;
+                        qeth_free_qdio_buffers(card);
+                }
                 card->info.initial_mtu = mtu;
+                card->info.max_mtu = mtu;
                 card->qdio.in_buf_size = mtu + 2 * PAGE_SIZE;
         } else {
                 card->info.initial_mtu = qeth_get_initial_mtu_for_card(card);