From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753831AbdLMCNR (ORCPT ); Tue, 12 Dec 2017 21:13:17 -0500 Received: from omzsmtpe03.verizonbusiness.com ([199.249.25.208]:39443 "EHLO omzsmtpe03.verizonbusiness.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753424AbdLMCBM (ORCPT ); Tue, 12 Dec 2017 21:01:12 -0500 From: alexander.levin@verizon.com Cc: Julian Wiedmann , Ursula Braun , "David S . Miller" , alexander.levin@verizon.com X-Host: mariner.tdc.vzwcorp.com To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [PATCH AUTOSEL for 3.18 16/40] s390/qeth: no ETH header for outbound AF_IUCV Thread-Topic: [PATCH AUTOSEL for 3.18 16/40] s390/qeth: no ETH header for outbound AF_IUCV Thread-Index: AQHTc7X6IbUhLN9AgEeCFRxMD7PTDg== Date: Wed, 13 Dec 2017 01:59:15 +0000 Message-ID: <20171213015905.7059-16-alexander.levin@verizon.com> References: <20171213015905.7059-1-alexander.levin@verizon.com> In-Reply-To: <20171213015905.7059-1-alexander.levin@verizon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id vBD2DLSC016890 From: Julian Wiedmann [ Upstream commit acd9776b5c45ef02d1a210969a6fcc058afb76e3 ] With AF_IUCV traffic, the skb passed to hard_start_xmit() has a 14 byte slot at skb->data, intended for an ETH header. qeth_l3_fill_af_iucv_hdr() fills this ETH header... and then immediately moves it to the skb's headroom, where it disappears and is never seen again. But it's still possible for us to return NETDEV_TX_BUSY after the skb has been modified. Since we didn't get a private copy of the skb, the next time the skb is delivered to hard_start_xmit() it no longer has the expected layout (we moved the ETH header to the headroom, so skb->data now starts at the IUCV_TRANS header). So when qeth_l3_fill_af_iucv_hdr() does another round of rebuilding, the resulting qeth header ends up all wrong. On transmission, the buffer is then rejected by the HiperSockets device with SBALF15 = x'04'. When this error is passed back to af_iucv as TX_NOTIFY_UNREACHABLE, it tears down the offending socket. As the ETH header for AF_IUCV serves no purpose, just align the code to what we do for IP traffic on L3 HiperSockets: keep the ETH header at skb->data, and pass down data_offset = ETH_HLEN to qeth_fill_buffer(). When mapping the payload into the SBAL elements, the ETH header is then stripped off. This avoids the skb manipulations in qeth_l3_fill_af_iucv_hdr(), and any buffer re-entering hard_start_xmit() after NETDEV_TX_BUSY is now processed properly. Signed-off-by: Julian Wiedmann Signed-off-by: Ursula Braun Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/s390/net/qeth_l3_main.c | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-) diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c index e5f8031ba317..b70c8b139b58 100644 --- a/drivers/s390/net/qeth_l3_main.c +++ b/drivers/s390/net/qeth_l3_main.c @@ -2769,17 +2769,13 @@ static void qeth_l3_fill_af_iucv_hdr(struct qeth_card *card, char daddr[16]; struct af_iucv_trans_hdr *iucv_hdr; - skb_pull(skb, 14); - card->dev->header_ops->create(skb, card->dev, 0, - card->dev->dev_addr, card->dev->dev_addr, - card->dev->addr_len); - skb_pull(skb, 14); - iucv_hdr = (struct af_iucv_trans_hdr *)skb->data; memset(hdr, 0, sizeof(struct qeth_hdr)); hdr->hdr.l3.id = QETH_HEADER_TYPE_LAYER3; hdr->hdr.l3.ext_flags = 0; - hdr->hdr.l3.length = skb->len; + hdr->hdr.l3.length = skb->len - ETH_HLEN; hdr->hdr.l3.flags = QETH_HDR_IPV6 | QETH_CAST_UNICAST; + + iucv_hdr = (struct af_iucv_trans_hdr *) (skb->data + ETH_HLEN); memset(daddr, 0, sizeof(daddr)); daddr[0] = 0xfe; daddr[1] = 0x80; @@ -2962,10 +2958,7 @@ static int qeth_l3_hard_start_xmit(struct sk_buff *skb, struct net_device *dev) if ((card->info.type == QETH_CARD_TYPE_IQD) && (!large_send) && (skb_shinfo(skb)->nr_frags == 0)) { new_skb = skb; - if (new_skb->protocol == ETH_P_AF_IUCV) - data_offset = 0; - else - data_offset = ETH_HLEN; + data_offset = ETH_HLEN; hdr = kmem_cache_alloc(qeth_core_header_cache, GFP_ATOMIC); if (!hdr) goto tx_drop; -- 2.11.0