From: Julian Wiedmann <jwi@linux.ibm.com>
Subject: s390/qeth: clean up l3_get_cast_type()
Patch-mainline: v4.16-rc1
Git-commit: 1f9791235b58eb4b5e61ed51c76a8d89dd09e042
References: FATE#326350, LTC#169511, bsc#1113509

Summary:     qeth: performance improvements
Description: This adds recent functional and performance improvements for the
             qeth network driver.
             Primarily this brings Scatter-Gather support for HiperSockets,
             reduced CPU consumption in the L3 IPv4 transmit path for OSA,
             improved Promiscuous Mode performance due to IFF_UNICAST_FLT,
             support for Scatter-Gather on z/VM virtual NICs, and
             support for delayed GRO flushing.

             For sanity & stability reasons, this effectively constitutes a
             backport of the qeth device driver from 4.19 mainline.
             

Upstream-Description:

             s390/qeth: clean up l3_get_cast_type()

             Use the proper helpers to check for multicast IP addressing, and remove
             some ancient Token Ring code.

             Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
             Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/s390/net/qeth_core.h    |    3 --
 drivers/s390/net/qeth_l3_main.c |   52 +++++++++++++++-------------------------
 2 files changed, 20 insertions(+), 35 deletions(-)

--- a/drivers/s390/net/qeth_core.h
+++ b/drivers/s390/net/qeth_core.h
@@ -505,9 +505,6 @@ struct qeth_qdio_info {
 
 #define QETH_ETH_MAC_V4      0x0100 /* like v4 */
 #define QETH_ETH_MAC_V6      0x3333 /* like v6 */
-/* tr mc mac is longer, but that will be enough to detect mc frames */
-#define QETH_TR_MAC_NC       0xc000 /* non-canonical */
-#define QETH_TR_MAC_C        0x0300 /* canonical */
 
 /**
  * buffer stuff for read channel
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -17,6 +17,7 @@
 #include <linux/kernel.h>
 #include <linux/etherdevice.h>
 #include <linux/ip.h>
+#include <linux/in.h>
 #include <linux/ipv6.h>
 #include <linux/inetdevice.h>
 #include <linux/igmp.h>
@@ -26,6 +27,7 @@
 #include <net/ip.h>
 #include <net/arp.h>
 #include <net/route.h>
+#include <net/ipv6.h>
 #include <net/ip6_fib.h>
 #include <net/ip6_checksum.h>
 #include <net/iucv/af_iucv.h>
@@ -2340,9 +2342,9 @@ static int qeth_l3_do_ioctl(struct net_d
 	return rc;
 }
 
-static int qeth_l3_get_cast_type(struct qeth_card *card, struct sk_buff *skb)
+static int qeth_l3_get_cast_type(struct sk_buff *skb)
 {
-	int cast_type = RTN_UNSPEC;
+	u16 hdr_mac = *((u16 *)skb->data);
 	struct neighbour *n = NULL;
 	struct dst_entry *dst;
 
@@ -2351,48 +2353,34 @@ static int qeth_l3_get_cast_type(struct
 	if (dst)
 		n = dst_neigh_lookup_skb(dst, skb);
 	if (n) {
-		cast_type = n->type;
+		int cast_type = n->type;
+
 		rcu_read_unlock();
 		neigh_release(n);
 		if ((cast_type == RTN_BROADCAST) ||
 		    (cast_type == RTN_MULTICAST) ||
 		    (cast_type == RTN_ANYCAST))
 			return cast_type;
-		else
-			return RTN_UNSPEC;
+		return RTN_UNSPEC;
 	}
 	rcu_read_unlock();
 
-	/* try something else */
+	/* no neighbour (eg AF_PACKET), fall back to target's IP address ... */
 	if (be16_to_cpu(skb->protocol) == ETH_P_IPV6)
-		return (skb_network_header(skb)[24] == 0xff) ?
-				RTN_MULTICAST : 0;
+		return ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ?
+				RTN_MULTICAST : RTN_UNSPEC;
 	else if (be16_to_cpu(skb->protocol) == ETH_P_IP)
-		return ((skb_network_header(skb)[16] & 0xf0) == 0xe0) ?
-				RTN_MULTICAST : 0;
-	/* ... */
+		return ipv4_is_multicast(ip_hdr(skb)->daddr) ?
+				RTN_MULTICAST : RTN_UNSPEC;
+
+	/* ... and MAC address */
 	if (ether_addr_equal_64bits(eth_hdr(skb)->h_dest, skb->dev->broadcast))
 		return RTN_BROADCAST;
-	else {
-		u16 hdr_mac;
-
-		hdr_mac = *((u16 *)skb->data);
-		/* tr multicast? */
-		switch (card->info.link_type) {
-		case QETH_LINK_TYPE_HSTR:
-		case QETH_LINK_TYPE_LANE_TR:
-			if ((hdr_mac == QETH_TR_MAC_NC) ||
-			    (hdr_mac == QETH_TR_MAC_C))
-				return RTN_MULTICAST;
-			break;
-		/* eth or so multicast? */
-		default:
-		if ((hdr_mac == QETH_ETH_MAC_V4) ||
-			    (hdr_mac == QETH_ETH_MAC_V6))
-				return RTN_MULTICAST;
-		}
-	}
-	return cast_type;
+	if (hdr_mac == QETH_ETH_MAC_V4 || hdr_mac == QETH_ETH_MAC_V6)
+		return RTN_MULTICAST;
+
+	/* default to unicast */
+	return RTN_UNSPEC;
 }
 
 static void qeth_l3_fill_af_iucv_hdr(struct qeth_card *card,
@@ -2574,7 +2562,7 @@ static netdev_tx_t qeth_l3_hard_start_xm
 	struct qeth_card *card = dev->ml_priv;
 	struct sk_buff *new_skb = NULL;
 	int ipv = qeth_get_ip_version(skb);
-	int cast_type = qeth_l3_get_cast_type(card, skb);
+	int cast_type = qeth_l3_get_cast_type(skb);
 	struct qeth_qdio_out_q *queue =
 		card->qdio.out_qs[card->qdio.do_prio_queueing
 			|| (cast_type && card->info.is_multicast_different) ?