diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index ca72f3311004..c8b308cfabf1 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -2134,24 +2134,25 @@ int qeth_send_control_data(struct qeth_card *card, int len,
 	}
 	reply->callback = reply_cb;
 	reply->param = reply_param;
-	if (card->state == CARD_STATE_DOWN)
-		reply->seqno = QETH_IDX_COMMAND_SEQNO;
-	else
-		reply->seqno = card->seqno.ipa++;
+
 	init_waitqueue_head(&reply->wait_q);
-	spin_lock_irqsave(&card->lock, flags);
-	list_add_tail(&reply->list, &card->cmd_waiter_list);
-	spin_unlock_irqrestore(&card->lock, flags);
 
 	while (atomic_cmpxchg(&card->write.irq_pending, 0, 1)) ;
-	qeth_prepare_control_data(card, len, iob);
 
 	if (IS_IPA(iob->data)) {
 		cmd = __ipa_cmd(iob);
+		cmd->hdr.seqno = card->seqno.ipa++;
+		reply->seqno = cmd->hdr.seqno;
 		event_timeout = QETH_IPA_TIMEOUT;
 	} else {
+		reply->seqno = QETH_IDX_COMMAND_SEQNO;
 		event_timeout = QETH_TIMEOUT;
 	}
+	qeth_prepare_control_data(card, len, iob);
+
+	spin_lock_irqsave(&card->lock, flags);
+	list_add_tail(&reply->list, &card->cmd_waiter_list);
+	spin_unlock_irqrestore(&card->lock, flags);
 
 	timeout = jiffies + event_timeout;
 
@@ -2933,7 +2934,7 @@ static void qeth_fill_ipacmd_header(struct qeth_card *card,
 	memset(cmd, 0, sizeof(struct qeth_ipa_cmd));
 	cmd->hdr.command = command;
 	cmd->hdr.initiator = IPA_CMD_INITIATOR_HOST;
-	cmd->hdr.seqno = card->seqno.ipa;
+	/* cmd->hdr.seqno is set by qeth_send_control_data() */
 	cmd->hdr.adapter_type = qeth_get_ipa_adp_type(card->info.link_type);
 	cmd->hdr.rel_adapter_no = (__u8) card->info.portno;
 	if (card->options.layer2)
@@ -3898,10 +3899,12 @@ EXPORT_SYMBOL_GPL(qeth_get_elements_for_frags);
 int qeth_get_elements_no(struct qeth_card *card,
 		     struct sk_buff *skb, int extra_elems, int data_offset)
 {
-	int elements = qeth_get_elements_for_range(
-				(addr_t)skb->data + data_offset,
-				(addr_t)skb->data + skb_headlen(skb)) +
-			qeth_get_elements_for_frags(skb);
+	addr_t end = (addr_t)skb->data + skb_headlen(skb);
+	int elements = qeth_get_elements_for_frags(skb);
+	addr_t start = (addr_t)skb->data + data_offset;
+
+	if (start != end)
+		elements += qeth_get_elements_for_range(start, end);
 
 	if ((elements + extra_elems) > QETH_MAX_BUFFER_ELEMENTS(card)) {
 		QETH_DBF_MESSAGE(2, "Invalid size of IP packet "
diff --git a/drivers/s390/net/qeth_l3.h b/drivers/s390/net/qeth_l3.h
index bdd45f4dcace..498fe9af2cdb 100644
--- a/drivers/s390/net/qeth_l3.h
+++ b/drivers/s390/net/qeth_l3.h
@@ -40,8 +40,40 @@ struct qeth_ipaddr {
 			unsigned int pfxlen;
 		} a6;
 	} u;
-
 };
+
+static inline bool qeth_l3_addr_match_ip(struct qeth_ipaddr *a1,
+					 struct qeth_ipaddr *a2)
+{
+	if (a1->proto != a2->proto)
+		return false;
+	if (a1->proto == QETH_PROT_IPV6)
+		return ipv6_addr_equal(&a1->u.a6.addr, &a2->u.a6.addr);
+	return a1->u.a4.addr == a2->u.a4.addr;
+}
+
+static inline bool qeth_l3_addr_match_all(struct qeth_ipaddr *a1,
+					  struct qeth_ipaddr *a2)
+{
+	/* Assumes that the pair was obtained via qeth_l3_addr_find_by_ip(),
+	 * so 'proto' and 'addr' match for sure.
+	 *
+	 * For ucast:
+	 * -	'mac' is always 0.
+	 * -	'mask'/'pfxlen' for RXIP/VIPA is always 0. For NORMAL, matching
+	 *	values are required to avoid mixups in takeover eligibility.
+	 *
+	 * For mcast,
+	 * -	'mac' is mapped from the IP, and thus always matches.
+	 * -	'mask'/'pfxlen' is always 0.
+	 */
+	if (a1->type != a2->type)
+		return false;
+	if (a1->proto == QETH_PROT_IPV6)
+		return a1->u.a6.pfxlen == a2->u.a6.pfxlen;
+	return a1->u.a4.mask == a2->u.a4.mask;
+}
+
 static inline  u64 qeth_l3_ipaddr_hash(struct qeth_ipaddr *addr)
 {
 	u64  ret = 0;
diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c
index b0c888e86cd4..962a04b68dd2 100644
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -67,6 +67,24 @@ void qeth_l3_ipaddr_to_string(enum qeth_prot_versions proto, const __u8 *addr,
 		qeth_l3_ipaddr6_to_string(addr, buf);
 }
 
+static struct qeth_ipaddr *qeth_l3_find_addr_by_ip(struct qeth_card *card,
+						   struct qeth_ipaddr *query)
+{
+	u64 key = qeth_l3_ipaddr_hash(query);
+	struct qeth_ipaddr *addr;
+
+	if (query->is_multicast) {
+		hash_for_each_possible(card->ip_mc_htable, addr, hnode, key)
+			if (qeth_l3_addr_match_ip(addr, query))
+				return addr;
+	} else {
+		hash_for_each_possible(card->ip_htable,  addr, hnode, key)
+			if (qeth_l3_addr_match_ip(addr, query))
+				return addr;
+	}
+	return NULL;
+}
+
 static void qeth_l3_convert_addr_to_bits(u8 *addr, u8 *bits, int len)
 {
 	int i, j;
@@ -120,34 +138,6 @@ static bool qeth_l3_is_addr_covered_by_ipato(struct qeth_card *card,
 	return rc;
 }
 
-inline int
-qeth_l3_ipaddrs_is_equal(struct qeth_ipaddr *addr1, struct qeth_ipaddr *addr2)
-{
-	return addr1->proto == addr2->proto &&
-	       !memcmp(&addr1->u, &addr2->u, sizeof(addr1->u)) &&
-	       ether_addr_equal_64bits(addr1->mac, addr2->mac);
-}
-
-static struct qeth_ipaddr *
-qeth_l3_ip_from_hash(struct qeth_card *card, struct qeth_ipaddr *tmp_addr)
-{
-	struct qeth_ipaddr *addr;
-
-	if (tmp_addr->is_multicast) {
-		hash_for_each_possible(card->ip_mc_htable,  addr,
-				hnode, qeth_l3_ipaddr_hash(tmp_addr))
-			if (qeth_l3_ipaddrs_is_equal(tmp_addr, addr))
-				return addr;
-	} else {
-		hash_for_each_possible(card->ip_htable,  addr,
-				hnode, qeth_l3_ipaddr_hash(tmp_addr))
-			if (qeth_l3_ipaddrs_is_equal(tmp_addr, addr))
-				return addr;
-	}
-
-	return NULL;
-}
-
 int qeth_l3_delete_ip(struct qeth_card *card, struct qeth_ipaddr *tmp_addr)
 {
 	int rc = 0;
@@ -162,23 +152,18 @@ int qeth_l3_delete_ip(struct qeth_card *card, struct qeth_ipaddr *tmp_addr)
 		QETH_CARD_HEX(card, 4, ((char *)&tmp_addr->u.a6.addr) + 8, 8);
 	}
 
-	addr = qeth_l3_ip_from_hash(card, tmp_addr);
-	if (!addr)
+	addr = qeth_l3_find_addr_by_ip(card, tmp_addr);
+	if (!addr || !qeth_l3_addr_match_all(addr, tmp_addr))
 		return -ENOENT;
 
 	addr->ref_counter--;
-	if (addr->ref_counter > 0 && (addr->type == QETH_IP_TYPE_NORMAL ||
-				      addr->type == QETH_IP_TYPE_RXIP))
+	if (addr->type == QETH_IP_TYPE_NORMAL && addr->ref_counter > 0)
 		return rc;
 	if (addr->in_progress)
 		return -EINPROGRESS;
 
-	if (!qeth_card_hw_is_reachable(card)) {
-		addr->disp_flag = QETH_DISP_ADDR_DELETE;
-		return 0;
-	}
-
-	rc = qeth_l3_deregister_addr_entry(card, addr);
+	if (qeth_card_hw_is_reachable(card))
+		rc = qeth_l3_deregister_addr_entry(card, addr);
 
 	hash_del(&addr->hnode);
 	kfree(addr);
@@ -190,6 +175,7 @@ int qeth_l3_add_ip(struct qeth_card *card, struct qeth_ipaddr *tmp_addr)
 {
 	int rc = 0;
 	struct qeth_ipaddr *addr;
+	char buf[40];
 
 	QETH_CARD_TEXT(card, 4, "addip");
 
@@ -200,8 +186,20 @@ int qeth_l3_add_ip(struct qeth_card *card, struct qeth_ipaddr *tmp_addr)
 		QETH_CARD_HEX(card, 4, ((char *)&tmp_addr->u.a6.addr) + 8, 8);
 	}
 
-	addr = qeth_l3_ip_from_hash(card, tmp_addr);
-	if (!addr) {
+	addr = qeth_l3_find_addr_by_ip(card, tmp_addr);
+	if (addr) {
+		if (tmp_addr->type != QETH_IP_TYPE_NORMAL)
+			return -EADDRINUSE;
+		if (qeth_l3_addr_match_all(addr, tmp_addr)) {
+			addr->ref_counter++;
+			return 0;
+		}
+		qeth_l3_ipaddr_to_string(tmp_addr->proto, (u8 *)&tmp_addr->u,
+					 buf);
+		dev_warn(&card->gdev->dev,
+			 "Registering IP address %s failed\n", buf);
+		return -EADDRINUSE;
+	} else {
 		addr = qeth_l3_get_addr_buffer(tmp_addr->proto);
 		if (!addr)
 			return -ENOMEM;
@@ -241,19 +239,15 @@ int qeth_l3_add_ip(struct qeth_card *card, struct qeth_ipaddr *tmp_addr)
 				(rc == IPA_RC_LAN_OFFLINE)) {
 			addr->disp_flag = QETH_DISP_ADDR_DO_NOTHING;
 			if (addr->ref_counter < 1) {
-				qeth_l3_delete_ip(card, addr);
+				qeth_l3_deregister_addr_entry(card, addr);
+				hash_del(&addr->hnode);
 				kfree(addr);
 			}
 		} else {
 			hash_del(&addr->hnode);
 			kfree(addr);
 		}
-	} else {
-		if (addr->type == QETH_IP_TYPE_NORMAL ||
-		    addr->type == QETH_IP_TYPE_RXIP)
-			addr->ref_counter++;
 	}
-
 	return rc;
 }
 
@@ -321,11 +315,7 @@ static void qeth_l3_recover_ip(struct qeth_card *card)
 	spin_lock_bh(&card->ip_lock);
 
 	hash_for_each_safe(card->ip_htable, i, tmp, addr, hnode) {
-		if (addr->disp_flag == QETH_DISP_ADDR_DELETE) {
-			qeth_l3_deregister_addr_entry(card, addr);
-			hash_del(&addr->hnode);
-			kfree(addr);
-		} else if (addr->disp_flag == QETH_DISP_ADDR_ADD) {
+		if (addr->disp_flag == QETH_DISP_ADDR_ADD) {
 			if (addr->proto == QETH_PROT_IPV4) {
 				addr->in_progress = 1;
 				spin_unlock_bh(&card->ip_lock);
@@ -643,12 +633,7 @@ int qeth_l3_add_vipa(struct qeth_card *card, enum qeth_prot_versions proto,
 		return -ENOMEM;
 
 	spin_lock_bh(&card->ip_lock);
-
-	if (qeth_l3_ip_from_hash(card, ipaddr))
-		rc = -EEXIST;
-	else
-		rc = qeth_l3_add_ip(card, ipaddr);
-
+	rc = qeth_l3_add_ip(card, ipaddr);
 	spin_unlock_bh(&card->ip_lock);
 
 	kfree(ipaddr);
@@ -713,12 +698,7 @@ int qeth_l3_add_rxip(struct qeth_card *card, enum qeth_prot_versions proto,
 		return -ENOMEM;
 
 	spin_lock_bh(&card->ip_lock);
-
-	if (qeth_l3_ip_from_hash(card, ipaddr))
-		rc = -EEXIST;
-	else
-		rc = qeth_l3_add_ip(card, ipaddr);
-
+	rc = qeth_l3_add_ip(card, ipaddr);
 	spin_unlock_bh(&card->ip_lock);
 
 	kfree(ipaddr);
@@ -1239,8 +1219,9 @@ qeth_l3_add_mc_to_hash(struct qeth_card *card, struct in_device *in4_dev)
 		tmp->u.a4.addr = be32_to_cpu(im4->multiaddr);
 		tmp->is_multicast = 1;
 
-		ipm = qeth_l3_ip_from_hash(card, tmp);
+		ipm = qeth_l3_find_addr_by_ip(card, tmp);
 		if (ipm) {
+			/* for mcast, by-IP match means full match */
 			ipm->disp_flag = QETH_DISP_ADDR_DO_NOTHING;
 		} else {
 			ipm = qeth_l3_get_addr_buffer(QETH_PROT_IPV4);
@@ -1319,8 +1300,9 @@ static void qeth_l3_add_mc6_to_hash(struct qeth_card *card,
 		       sizeof(struct in6_addr));
 		tmp->is_multicast = 1;
 
-		ipm = qeth_l3_ip_from_hash(card, tmp);
+		ipm = qeth_l3_find_addr_by_ip(card, tmp);
 		if (ipm) {
+			/* for mcast, by-IP match means full match */
 			ipm->disp_flag = QETH_DISP_ADDR_DO_NOTHING;
 			continue;
 		}
@@ -2450,11 +2432,12 @@ static void qeth_tso_fill_header(struct qeth_card *card,
 static int qeth_l3_get_elements_no_tso(struct qeth_card *card,
 			struct sk_buff *skb, int extra_elems)
 {
-	addr_t tcpdptr = (addr_t)tcp_hdr(skb) + tcp_hdrlen(skb);
-	int elements = qeth_get_elements_for_range(
-				tcpdptr,
-				(addr_t)skb->data + skb_headlen(skb)) +
-				qeth_get_elements_for_frags(skb);
+	addr_t start = (addr_t)tcp_hdr(skb) + tcp_hdrlen(skb);
+	addr_t end = (addr_t)skb->data + skb_headlen(skb);
+	int elements = qeth_get_elements_for_frags(skb);
+
+	if (start != end)
+		elements += qeth_get_elements_for_range(start, end);
 
 	if ((elements + extra_elems) > QETH_MAX_BUFFER_ELEMENTS(card)) {
 		QETH_DBF_MESSAGE(2,