qeth: allow HiperSockets framesize change in suspend

For HiperSockets the framesize-definition determines the selected
mtu-size and the size of the allocated qdio buffers.
A framesize-change may occur while a Linux system with probed
HiperSockets device is in suspend state. This patch enables proper
resuming of a HiperSockets device in this case.
Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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);