Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934774AbcKML1C (ORCPT ); Sun, 13 Nov 2016 06:27:02 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:36122 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933754AbcKML07 (ORCPT ); Sun, 13 Nov 2016 06:26:59 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ben Greear , Paolo Abeni , "David S. Miller" Subject: [PATCH 4.4 09/34] net: pktgen: fix pkt_size Date: Sun, 13 Nov 2016 12:24:41 +0100 Message-Id: <20161113112400.469416276@linuxfoundation.org> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20161113112400.008903838@linuxfoundation.org> References: <20161113112400.008903838@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3491 Lines: 108 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paolo Abeni [ Upstream commit 63d75463c91a5b5be7c0aca11ceb45ea5a0ae81d ] The commit 879c7220e828 ("net: pktgen: Observe needed_headroom of the device") increased the 'pkt_overhead' field value by LL_RESERVED_SPACE. As a side effect the generated packet size, computed as: /* Eth + IPh + UDPh + mpls */ datalen = pkt_dev->cur_pkt_size - 14 - 20 - 8 - pkt_dev->pkt_overhead; is decreased by the same value. The above changed slightly the behavior of existing pktgen users, and made the procfs interface somewhat inconsistent. Fix it by restoring the previous pkt_overhead value and using LL_RESERVED_SPACE as extralen in skb allocation. Also, change pktgen_alloc_skb() to only partially reserve the headroom to allow the caller to prefetch from ll header start. v1 -> v2: - fixed some typos in the comments Fixes: 879c7220e828 ("net: pktgen: Observe needed_headroom of the device") Suggested-by: Ben Greear Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/pktgen.c | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) --- a/net/core/pktgen.c +++ b/net/core/pktgen.c @@ -2278,7 +2278,7 @@ static void spin(struct pktgen_dev *pkt_ static inline void set_pkt_overhead(struct pktgen_dev *pkt_dev) { - pkt_dev->pkt_overhead = LL_RESERVED_SPACE(pkt_dev->odev); + pkt_dev->pkt_overhead = 0; pkt_dev->pkt_overhead += pkt_dev->nr_labels*sizeof(u32); pkt_dev->pkt_overhead += VLAN_TAG_SIZE(pkt_dev); pkt_dev->pkt_overhead += SVLAN_TAG_SIZE(pkt_dev); @@ -2769,13 +2769,13 @@ static void pktgen_finalize_skb(struct p } static struct sk_buff *pktgen_alloc_skb(struct net_device *dev, - struct pktgen_dev *pkt_dev, - unsigned int extralen) + struct pktgen_dev *pkt_dev) { + unsigned int extralen = LL_RESERVED_SPACE(dev); struct sk_buff *skb = NULL; - unsigned int size = pkt_dev->cur_pkt_size + 64 + extralen + - pkt_dev->pkt_overhead; + unsigned int size; + size = pkt_dev->cur_pkt_size + 64 + extralen + pkt_dev->pkt_overhead; if (pkt_dev->flags & F_NODE) { int node = pkt_dev->node >= 0 ? pkt_dev->node : numa_node_id(); @@ -2788,8 +2788,9 @@ static struct sk_buff *pktgen_alloc_skb( skb = __netdev_alloc_skb(dev, size, GFP_NOWAIT); } + /* the caller pre-fetches from skb->data and reserves for the mac hdr */ if (likely(skb)) - skb_reserve(skb, LL_RESERVED_SPACE(dev)); + skb_reserve(skb, extralen - 16); return skb; } @@ -2822,16 +2823,14 @@ static struct sk_buff *fill_packet_ipv4( mod_cur_headers(pkt_dev); queue_map = pkt_dev->cur_queue_map; - datalen = (odev->hard_header_len + 16) & ~0xf; - - skb = pktgen_alloc_skb(odev, pkt_dev, datalen); + skb = pktgen_alloc_skb(odev, pkt_dev); if (!skb) { sprintf(pkt_dev->result, "No memory"); return NULL; } prefetchw(skb->data); - skb_reserve(skb, datalen); + skb_reserve(skb, 16); /* Reserve for ethernet and IP header */ eth = (__u8 *) skb_push(skb, 14); @@ -2951,7 +2950,7 @@ static struct sk_buff *fill_packet_ipv6( mod_cur_headers(pkt_dev); queue_map = pkt_dev->cur_queue_map; - skb = pktgen_alloc_skb(odev, pkt_dev, 16); + skb = pktgen_alloc_skb(odev, pkt_dev); if (!skb) { sprintf(pkt_dev->result, "No memory"); return NULL;