[PATCH net-next 06/13] s390/qeth: clean up initial MTU determination

Julian Wiedmann
2017-10-18T15:40:18Z

1. Drop the support for Token Ring,
2. use the ETH_DATA_LEN macro for the default L2 MTU,
3. handle OSM via the default case (as OSM is L2-only), and
4. document why the L3 MTU is reduced.

Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
---
drivers/s390/net/qeth_core_main.c | 14 ++++----------
1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 735b03cae727..acf16fa75c63 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -2219,18 +2219,12 @@ static int qeth_get_initial_mtu_for_card(struct qeth_card *card)
case QETH_CARD_TYPE_IQD:
return card->info.max_mtu;
case QETH_CARD_TYPE_OSD:
- switch (card->info.link_type) {
- case QETH_LINK_TYPE_HSTR:
- case QETH_LINK_TYPE_LANE_TR:
- return 2000;
- default:
- return card->options.layer2 ? 1500 : 1492;
- }
- case QETH_CARD_TYPE_OSM:
case QETH_CARD_TYPE_OSX:
- return card->options.layer2 ? 1500 : 1492;
+ if (!card->options.layer2)
+ return ETH_DATA_LEN - 8; /* L3: allow for LLC + SNAP */
+ /* fall through */
default:
- return 1500;
+ return ETH_DATA_LEN;
}
}

--
2.13.5