s390/qeth: utilize virtual MAC for Layer2 OSD devices

By default, READ MAC on a Layer2 OSD device returns the adapter's
burnt-in MAC address. Given the default scenario of many virtual devices
on the same adapter, qeth can't make any use of this address and
therefore skips the READ MAC call for this device type.

But in some configurations, the READ MAC command for a Layer2 OSD device
actually returns a pre-provisioned, virtual MAC address. So enable the
READ MAC code to detect this situation, and let the L2 subdriver
call READ MAC for OSD devices.

This also removes the QETH_LAYER2_MAC_READ flag, which protects L2
devices against calling READ MAC multiple times. Instead protect the
whole call to qeth_l2_request_initial_mac().
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/s390/net/qeth_core.h

@@ -665,7 +665,6 @@ struct qeth_card_blkt {
 
 #define QETH_BROADCAST_WITH_ECHO    0x01
 #define QETH_BROADCAST_WITHOUT_ECHO 0x02
-#define QETH_LAYER2_MAC_READ	    0x01
 #define QETH_LAYER2_MAC_REGISTERED  0x02
 struct qeth_card_info {
 	unsigned short unit_addr2;

drivers/s390/net/qeth_core_main.c

@@ -4235,16 +4235,18 @@ static int qeth_setadpparms_change_macaddr_cb(struct qeth_card *card,
 		struct qeth_reply *reply, unsigned long data)
 {
 	struct qeth_ipa_cmd *cmd = (struct qeth_ipa_cmd *) data;
+	struct qeth_ipacmd_setadpparms *adp_cmd;
 
 	QETH_CARD_TEXT(card, 4, "chgmaccb");
 	if (qeth_setadpparms_inspect_rc(cmd))
 		return 0;
 
-	if (IS_LAYER3(card) || !(card->info.mac_bits & QETH_LAYER2_MAC_READ)) {
-		ether_addr_copy(card->dev->dev_addr,
-				cmd->data.setadapterparms.data.change_addr.addr);
-		card->info.mac_bits |= QETH_LAYER2_MAC_READ;
-	}
+	adp_cmd = &cmd->data.setadapterparms;
+	if (IS_LAYER2(card) && IS_OSD(card) && !IS_VM_NIC(card) &&
+	    !(adp_cmd->hdr.flags & QETH_SETADP_FLAGS_VIRTUAL_MAC))
+		return 0;
+
+	ether_addr_copy(card->dev->dev_addr, adp_cmd->data.change_addr.addr);
 	return 0;
 }
 

drivers/s390/net/qeth_core_mpc.h

@@ -80,7 +80,9 @@ enum qeth_card_types {
 };
 
 #define IS_IQD(card)	((card)->info.type == QETH_CARD_TYPE_IQD)
+#define IS_OSD(card)	((card)->info.type == QETH_CARD_TYPE_OSD)
 #define IS_OSN(card)	((card)->info.type == QETH_CARD_TYPE_OSN)
+#define IS_VM_NIC(card)	((card)->info.guestlan)
 
 #define QETH_MPC_DIFINFO_LEN_INDICATES_LINK_TYPE 0x18
 /* only the first two bytes are looked at in qeth_get_cardname_short */
@@ -529,17 +531,20 @@ struct qeth_query_switch_attributes {
 	__u8  reserved3[8];
 };
 
+#define QETH_SETADP_FLAGS_VIRTUAL_MAC	0x80	/* for CHANGE_ADDR_READ_MAC */
+
 struct qeth_ipacmd_setadpparms_hdr {
-	__u32 supp_hw_cmds;
-	__u32 reserved1;
-	__u16 cmdlength;
-	__u16 reserved2;
-	__u32 command_code;
-	__u16 return_code;
-	__u8  used_total;
-	__u8  seq_no;
-	__u32 reserved3;
-} __attribute__ ((packed));
+	u32 supp_hw_cmds;
+	u32 reserved1;
+	u16 cmdlength;
+	u16 reserved2;
+	u32 command_code;
+	u16 return_code;
+	u8 used_total;
+	u8 seq_no;
+	u8 flags;
+	u8 reserved3[3];
+};
 
 struct qeth_ipacmd_setadpparms {
 	struct qeth_ipacmd_setadpparms_hdr hdr;

drivers/s390/net/qeth_l2_main.c

@@ -461,12 +461,9 @@ static int qeth_l2_request_initial_mac(struct qeth_card *card)
 		/* fall back to alternative mechanism: */
 	}
 
-	if (card->info.type == QETH_CARD_TYPE_IQD ||
-	    card->info.type == QETH_CARD_TYPE_OSM ||
-	    card->info.type == QETH_CARD_TYPE_OSX ||
-	    card->info.guestlan) {
+	if (!IS_OSN(card)) {
 		rc = qeth_setadpparms_change_macaddr(card);
-		if (!rc)
+		if (!rc && is_valid_ether_addr(card->dev->dev_addr))
 			goto out;
 		QETH_DBF_MESSAGE(2, "READ_MAC Assist failed on device %x: %#x\n",
 				 CARD_DEVID(card), rc);
@@ -917,7 +914,8 @@ static int qeth_l2_setup_netdev(struct qeth_card *card, bool carrier_ok)
 				       PAGE_SIZE * (QDIO_MAX_ELEMENTS_PER_BUFFER - 1));
 	}
 
-	qeth_l2_request_initial_mac(card);
+	if (!is_valid_ether_addr(card->dev->dev_addr))
+		qeth_l2_request_initial_mac(card);
 	netif_napi_add(card->dev, &card->napi, qeth_poll, QETH_NAPI_WEIGHT);
 	rc = register_netdev(card->dev);
 	if (!rc && carrier_ok)