qeth: add more strict MTU checking

HiperSockets and OSA hardware report a maximum MTU size. Add checking
to reject larger MTUs than allowed by hardware.

Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 31 deletions

diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 29f848bfc12f..ddeef41049ae 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -1832,33 +1832,6 @@ static inline int qeth_get_initial_mtu_for_card(struct qeth_card *card)
         }
 }
 
-static inline int qeth_get_max_mtu_for_card(int cardtype)
-{
-        switch (cardtype) {
-
-        case QETH_CARD_TYPE_UNKNOWN:
-        case QETH_CARD_TYPE_OSD:
-        case QETH_CARD_TYPE_OSN:
-        case QETH_CARD_TYPE_OSM:
-        case QETH_CARD_TYPE_OSX:
-                return 61440;
-        case QETH_CARD_TYPE_IQD:
-                return 57344;
-        default:
-                return 1500;
-        }
-}
-
-static inline int qeth_get_mtu_out_of_mpc(int cardtype)
-{
-        switch (cardtype) {
-        case QETH_CARD_TYPE_IQD:
-                return 1;
-        default:
-                return 0;
-        }
-}
-
 static inline int qeth_get_mtu_outof_framesize(int framesize)
 {
         switch (framesize) {
@@ -1881,10 +1854,9 @@ static inline int qeth_mtu_is_valid(struct qeth_card *card, int mtu)
         case QETH_CARD_TYPE_OSD:
         case QETH_CARD_TYPE_OSM:
         case QETH_CARD_TYPE_OSX:
-                return ((mtu >= 576) && (mtu <= 61440));
         case QETH_CARD_TYPE_IQD:
                 return ((mtu >= 576) &&
-                        (mtu <= card->info.max_mtu + 4096 - 32));
+                        (mtu <= card->info.max_mtu));
         case QETH_CARD_TYPE_OSN:
         case QETH_CARD_TYPE_UNKNOWN:
         default:
@@ -1907,7 +1879,7 @@ static int qeth_ulp_enable_cb(struct qeth_card *card, struct qeth_reply *reply,
         memcpy(&card->token.ulp_filter_r,
                QETH_ULP_ENABLE_RESP_FILTER_TOKEN(iob->data),
                QETH_MPC_TOKEN_LENGTH);
-        if (qeth_get_mtu_out_of_mpc(card->info.type)) {
+        if (card->info.type == QETH_CARD_TYPE_IQD) {
                 memcpy(&framesize, QETH_ULP_ENABLE_RESP_MAX_MTU(iob->data), 2);
                 mtu = qeth_get_mtu_outof_framesize(framesize);
                 if (!mtu) {
@@ -1920,7 +1892,8 @@ static int qeth_ulp_enable_cb(struct qeth_card *card, struct qeth_reply *reply,
                 card->qdio.in_buf_size = mtu + 2 * PAGE_SIZE;
         } else {
                 card->info.initial_mtu = qeth_get_initial_mtu_for_card(card);
-                card->info.max_mtu = qeth_get_max_mtu_for_card(card->info.type);
+                card->info.max_mtu = *(__u16 *)QETH_ULP_ENABLE_RESP_MAX_MTU(
+                        iob->data);
                 card->qdio.in_buf_size = QETH_IN_BUF_SIZE_DEFAULT;
         }