From patchwork Mon Aug 20 06:18:45 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Patrick McHardy X-Patchwork-Id: 178666 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 0069C2C009A for ; Mon, 20 Aug 2012 16:19:09 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752911Ab2HTGS7 (ORCPT ); Mon, 20 Aug 2012 02:18:59 -0400 Received: from stinky.trash.net ([213.144.137.162]:36020 "EHLO stinky.trash.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752234Ab2HTGS5 (ORCPT ); Mon, 20 Aug 2012 02:18:57 -0400 Received: from zenbook.localnet (localhost [127.0.0.1]) by stinky.trash.net (Postfix) with ESMTP id 32289B2C4B; Mon, 20 Aug 2012 08:18:56 +0200 (MEST) From: Patrick McHardy To: Florian.Westphal@Sophos.com Cc: netdev@vger.kernel.org, netfilter-devel@vger.kernel.org Subject: [PATCH 04/11] netlink: add netlink_skb_set_owner_r() Date: Mon, 20 Aug 2012 08:18:45 +0200 Message-Id: <1345443532-3707-5-git-send-email-kaber@trash.net> X-Mailer: git-send-email 1.7.7.6 In-Reply-To: <1345443532-3707-1-git-send-email-kaber@trash.net> References: <1345443532-3707-1-git-send-email-kaber@trash.net> Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org For mmap'ed I/O a netlink specific skb destructor needs to be invoked after the final kfree_skb() to clean up state. This doesn't work currently since the skb's ownership is transfered to the receiving socket using skb_set_owner_r(), which orphans the skb, thereby invoking the destructor prematurely. Since netlink doesn't account skbs to the originating socket, there's no need to orphan the skb. Add a netlink specific skb_set_owner_r() variant that does not orphan the skb and use a netlink specific destructor to call sock_rfree(). Signed-off-by: Patrick McHardy --- net/netlink/af_netlink.c | 18 ++++++++++++++++-- 1 files changed, 16 insertions(+), 2 deletions(-) diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 3233601..e2d0177 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -166,6 +166,20 @@ static void netlink_consume_callback(struct netlink_callback *cb) kfree(cb); } +static void netlink_skb_destructor(struct sk_buff *skb) +{ + sock_rfree(skb); +} + +static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk) +{ + WARN_ON(skb->sk != NULL); + skb->sk = sk; + skb->destructor = netlink_skb_destructor; + atomic_add(skb->truesize, &sk->sk_rmem_alloc); + sk_mem_charge(sk, skb->truesize); +} + static void netlink_sock_destruct(struct sock *sk) { struct netlink_sock *nlk = nlk_sk(sk); @@ -855,7 +869,7 @@ int netlink_attachskb(struct sock *sk, struct sk_buff *skb, } return 1; } - skb_set_owner_r(skb, sk); + netlink_skb_set_owner_r(skb, sk); return 0; } @@ -924,7 +938,7 @@ static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb) ret = -ECONNREFUSED; if (nlk->netlink_rcv != NULL) { ret = skb->len; - skb_set_owner_r(skb, sk); + netlink_skb_set_owner_r(skb, sk); nlk->netlink_rcv(skb); consume_skb(skb); } else {