From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julian Wiedmann Subject: [PATCH net 3/5] s390/qeth: avoid using is_multicast_ether_addr_64bits on (u8 *)[6] Date: Fri, 29 Jun 2018 19:45:52 +0200 Message-ID: <20180629174554.53718-4-jwi@linux.ibm.com> References: <20180629174554.53718-1-jwi@linux.ibm.com> Cc: , , Martin Schwidefsky , Heiko Carstens , Stefan Raspl , Ursula Braun , Vasily Gorbik , Julian Wiedmann To: David Miller Return-path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:43200 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754453AbeF2RqN (ORCPT ); Fri, 29 Jun 2018 13:46:13 -0400 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w5THi5tq127271 for ; Fri, 29 Jun 2018 13:46:12 -0400 Received: from e06smtp05.uk.ibm.com (e06smtp05.uk.ibm.com [195.75.94.101]) by mx0a-001b2d01.pphosted.com with ESMTP id 2jwppe6xkd-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 29 Jun 2018 13:46:12 -0400 Received: from localhost by e06smtp05.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 29 Jun 2018 18:46:09 +0100 In-Reply-To: <20180629174554.53718-1-jwi@linux.ibm.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Vasily Gorbik *ether_addr*_64bits functions have been introduced to optimize performance critical paths, which access 6-byte ethernet address as u64 value to get "nice" assembly. A harmless hack works nicely on ethernet addresses shoved into a structure or a larger buffer, until busted by Kasan on smth like plain (u8 *)[6]. qeth_l2_set_mac_address calls qeth_l2_remove_mac passing u8 old_addr[ETH_ALEN] as an argument. Adding/removing macs for an ethernet adapter is not that performance critical. Moreover is_multicast_ether_addr_64bits itself on s390 is not faster than is_multicast_ether_addr: is_multicast_ether_addr(%r2) -> %r2 llc %r2,0(%r2) risbg %r2,%r2,63,191,0 is_multicast_ether_addr_64bits(%r2) -> %r2 llgc %r2,0(%r2) risbg %r2,%r2,63,191,0 So, let's just use is_multicast_ether_addr instead of is_multicast_ether_addr_64bits. Fixes: bcacfcbc82b4 ("s390/qeth: fix MAC address update sequence") Reviewed-by: Julian Wiedmann Signed-off-by: Vasily Gorbik Signed-off-by: Julian Wiedmann --- drivers/s390/net/qeth_l2_main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c index 7daf125dae76..5464515b71f1 100644 --- a/drivers/s390/net/qeth_l2_main.c +++ b/drivers/s390/net/qeth_l2_main.c @@ -140,7 +140,7 @@ static int qeth_l2_send_setmac(struct qeth_card *card, __u8 *mac) static int qeth_l2_write_mac(struct qeth_card *card, u8 *mac) { - enum qeth_ipa_cmds cmd = is_multicast_ether_addr_64bits(mac) ? + enum qeth_ipa_cmds cmd = is_multicast_ether_addr(mac) ? IPA_CMD_SETGMAC : IPA_CMD_SETVMAC; int rc; @@ -157,7 +157,7 @@ static int qeth_l2_write_mac(struct qeth_card *card, u8 *mac) static int qeth_l2_remove_mac(struct qeth_card *card, u8 *mac) { - enum qeth_ipa_cmds cmd = is_multicast_ether_addr_64bits(mac) ? + enum qeth_ipa_cmds cmd = is_multicast_ether_addr(mac) ? IPA_CMD_DELGMAC : IPA_CMD_DELVMAC; int rc; -- 2.16.4