From patchwork Wed Apr 17 16:47:00 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Patrick McHardy X-Patchwork-Id: 237315 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id C95032C0161 for ; Thu, 18 Apr 2013 02:48:17 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965085Ab3DQQsM (ORCPT ); Wed, 17 Apr 2013 12:48:12 -0400 Received: from stinky.trash.net ([213.144.137.162]:60952 "EHLO stinky.trash.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936093Ab3DQQr0 (ORCPT ); Wed, 17 Apr 2013 12:47:26 -0400 Received: from stinky.trash.net (unknown [127.0.0.1]) by stinky.trash.net (Postfix) with ESMTP id 3FE799D2E1; Wed, 17 Apr 2013 18:47:25 +0200 (MEST) From: Patrick McHardy To: davem@davemloft.net Cc: netfilter-devel@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH 05/14] netlink: add netlink_skb_set_owner_r() Date: Wed, 17 Apr 2013 18:47:00 +0200 Message-Id: <1366217229-22705-6-git-send-email-kaber@trash.net> X-Mailer: git-send-email 1.8.1.4 In-Reply-To: <1366217229-22705-1-git-send-email-kaber@trash.net> References: <1366217229-22705-1-git-send-email-kaber@trash.net> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@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 | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 26779c2..58b9025 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -119,6 +119,20 @@ 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); @@ -820,7 +834,7 @@ 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; } @@ -890,7 +904,7 @@ 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); NETLINK_CB(skb).sk = ssk; nlk->netlink_rcv(skb); consume_skb(skb); @@ -962,7 +976,7 @@ static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb) if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf && !test_bit(NETLINK_CONGESTED, &nlk->state)) { - skb_set_owner_r(skb, sk); + netlink_skb_set_owner_r(skb, sk); __netlink_sendskb(sk, skb); return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1); }