From: Julian Wiedmann <jwi@linux.ibm.com>
Subject: s390/qeth: don't verify device when setting MAC address
Patch-mainline: v4.15-rc1
Git-commit: 857d8ee2608831197d9838c8331b87848d05da33
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: don't verify device when setting MAC address

             There's no reason why l2_set_mac_address() should ever be called for
             a netdevice that's not owned by qeth. It's certainly not required for
             VLAN devices, which have their own netdev_ops.

             Also:
             1) we don't do such validation for any of the other netdev_ops routines.
             2) the code in question clearly has never been actually exercised;
                it's broken. After determining that the device is not owned
                by qeth, it would still use dev->ml_priv to write a qeth trace entry.

             Remove the check, and its helper that walked the global card list.

             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_l2_main.c |   23 -----------------------
 1 file changed, 23 deletions(-)

--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -38,24 +38,6 @@ static void qeth_l2_vnicc_init(struct qe
 static bool qeth_l2_vnicc_recover_timeout(struct qeth_card *card, u32 vnicc,
 					  u32 *timeout);
 
-static int qeth_l2_verify_dev(struct net_device *dev)
-{
-	struct qeth_card *card;
-	unsigned long flags;
-	int rc = 0;
-
-	read_lock_irqsave(&qeth_core_card_list.rwlock, flags);
-	list_for_each_entry(card, &qeth_core_card_list.list, list) {
-		if (card->dev == dev) {
-			rc = QETH_REAL_CARD;
-			break;
-		}
-	}
-	read_unlock_irqrestore(&qeth_core_card_list.rwlock, flags);
-
-	return rc;
-}
-
 static struct net_device *qeth_l2_netdev_by_devno(unsigned char *read_dev_no)
 {
 	struct qeth_card *card;
@@ -553,11 +535,6 @@ static int qeth_l2_set_mac_address(struc
 
 	QETH_CARD_TEXT(card, 3, "setmac");
 
-	if (qeth_l2_verify_dev(dev) != QETH_REAL_CARD) {
-		QETH_CARD_TEXT(card, 3, "setmcINV");
-		return -EOPNOTSUPP;
-	}
-
 	if (card->info.type == QETH_CARD_TYPE_OSN ||
 	    card->info.type == QETH_CARD_TYPE_OSM ||
 	    card->info.type == QETH_CARD_TYPE_OSX) {