Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965215AbcCIXVU (ORCPT ); Wed, 9 Mar 2016 18:21:20 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:41234 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965042AbcCIXTS (ORCPT ); Wed, 9 Mar 2016 18:19:18 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Hans Westgaard Ry , "David S . Miller" , Luis Henriques , Kamal Mostafa Subject: [PATCH 3.13.y-ckt 125/138] net:Add sysctl_max_skb_frags Date: Wed, 9 Mar 2016 15:14:12 -0800 Message-Id: <1457565265-15195-126-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.0 In-Reply-To: <1457565265-15195-1-git-send-email-kamal@canonical.com> References: <1457565265-15195-1-git-send-email-kamal@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Extended-Stable: 3.13 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3492 Lines: 108 3.13.11-ckt36 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Hans Westgaard Ry commit 5f74f82ea34c0da80ea0b49192bb5ea06e063593 upstream. Devices may have limits on the number of fragments in an skb they support. Current codebase uses a constant as maximum for number of fragments one skb can hold and use. When enabling scatter/gather and running traffic with many small messages the codebase uses the maximum number of fragments and may thereby violate the max for certain devices. The patch introduces a global variable as max number of fragments. Signed-off-by: Hans Westgaard Ry Reviewed-by: Håkon Bugge Acked-by: Eric Dumazet Signed-off-by: David S. Miller [ luis: backported to 3.16: adjusted context ] Signed-off-by: Luis Henriques Signed-off-by: Kamal Mostafa --- include/linux/skbuff.h | 1 + net/core/skbuff.c | 2 ++ net/core/sysctl_net_core.c | 10 ++++++++++ net/ipv4/tcp.c | 4 ++-- 4 files changed, 15 insertions(+), 2 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 090a81d..ab38ef2 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -148,6 +148,7 @@ struct sk_buff; #else #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 1) #endif +extern int sysctl_max_skb_frags; typedef struct skb_frag_struct skb_frag_t; diff --git a/net/core/skbuff.c b/net/core/skbuff.c index a6c16df..eb118c7 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -75,6 +75,8 @@ struct kmem_cache *skbuff_head_cache __read_mostly; static struct kmem_cache *skbuff_fclone_cache __read_mostly; +int sysctl_max_skb_frags __read_mostly = MAX_SKB_FRAGS; +EXPORT_SYMBOL(sysctl_max_skb_frags); /** * skb_panic - private function for out-of-line support diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index f3413ae..d796239 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -27,6 +27,7 @@ static int one = 1; static int ushort_max = USHRT_MAX; static int min_sndbuf = SOCK_MIN_SNDBUF; static int min_rcvbuf = SOCK_MIN_RCVBUF; +static int max_skb_frags = MAX_SKB_FRAGS; #ifdef CONFIG_RPS static int rps_sock_flow_sysctl(struct ctl_table *table, int write, @@ -362,6 +363,15 @@ static struct ctl_table net_core_table[] = { .mode = 0644, .proc_handler = proc_dointvec }, + { + .procname = "max_skb_frags", + .data = &sysctl_max_skb_frags, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &one, + .extra2 = &max_skb_frags, + }, { } }; diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index fda904e..43f384d 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -887,7 +887,7 @@ new_segment: i = skb_shinfo(skb)->nr_frags; can_coalesce = skb_can_coalesce(skb, i, page, offset); - if (!can_coalesce && i >= MAX_SKB_FRAGS) { + if (!can_coalesce && i >= sysctl_max_skb_frags) { tcp_mark_push(tp, skb); goto new_segment; } @@ -1170,7 +1170,7 @@ new_segment: if (!skb_can_coalesce(skb, i, pfrag->page, pfrag->offset)) { - if (i == MAX_SKB_FRAGS || !sg) { + if (i == sysctl_max_skb_frags || !sg) { tcp_mark_push(tp, skb); goto new_segment; } -- 2.7.0