From patchwork Tue Jan 14 07:41:03 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ying Xue X-Patchwork-Id: 310488 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 4CF5C2C0092 for ; Tue, 14 Jan 2014 18:45:35 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752659AbaANHmf (ORCPT ); Tue, 14 Jan 2014 02:42:35 -0500 Received: from mail.windriver.com ([147.11.1.11]:47568 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752148AbaANHmE (ORCPT ); Tue, 14 Jan 2014 02:42:04 -0500 Received: from ALA-HCB.corp.ad.wrs.com (ala-hcb.corp.ad.wrs.com [147.11.189.41]) by mail.windriver.com (8.14.5/8.14.5) with ESMTP id s0E7fe1I005413 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL); Mon, 13 Jan 2014 23:41:40 -0800 (PST) Received: from ying.corp.ad.wrs.com (128.224.162.185) by ALA-HCB.corp.ad.wrs.com (147.11.189.41) with Microsoft SMTP Server id 14.2.347.0; Mon, 13 Jan 2014 23:41:40 -0800 From: Ying Xue To: CC: , , , , , , , , Subject: [PATCH net-next 04/10] dcb: use __dev_get_by_name instead of dev_get_by_name to find interface Date: Tue, 14 Jan 2014 15:41:03 +0800 Message-ID: <1389685269-18600-5-git-send-email-ying.xue@windriver.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1389685269-18600-1-git-send-email-ying.xue@windriver.com> References: <1389685269-18600-1-git-send-email-ying.xue@windriver.com> MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The following call chain indicates that dcb_doit() is protected under rtnl_lock. So if we use __dev_get_by_name() instead of dev_get_by_name() to find interface handlers in it, this would help us avoid to change interface reference counter. rtnetlink_rcv() rtnl_lock() netlink_rcv_skb() dcb_doit() rtnl_unlock() Cc: John Fastabend Signed-off-by: Ying Xue --- net/dcb/dcbnl.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) diff --git a/net/dcb/dcbnl.c b/net/dcb/dcbnl.c index 66fbe19..5536444 100644 --- a/net/dcb/dcbnl.c +++ b/net/dcb/dcbnl.c @@ -1688,21 +1688,17 @@ static int dcb_doit(struct sk_buff *skb, struct nlmsghdr *nlh) if (!tb[DCB_ATTR_IFNAME]) return -EINVAL; - netdev = dev_get_by_name(net, nla_data(tb[DCB_ATTR_IFNAME])); + netdev = __dev_get_by_name(net, nla_data(tb[DCB_ATTR_IFNAME])); if (!netdev) return -ENODEV; - if (!netdev->dcbnl_ops) { - ret = -EOPNOTSUPP; - goto out; - } + if (!netdev->dcbnl_ops) + return -EOPNOTSUPP; reply_skb = dcbnl_newmsg(fn->type, dcb->cmd, portid, nlh->nlmsg_seq, nlh->nlmsg_flags, &reply_nlh); - if (!reply_skb) { - ret = -ENOBUFS; - goto out; - } + if (!reply_skb) + return -ENOBUFS; ret = fn->cb(netdev, nlh, nlh->nlmsg_seq, tb, reply_skb); if (ret < 0) { @@ -1714,7 +1710,6 @@ static int dcb_doit(struct sk_buff *skb, struct nlmsghdr *nlh) ret = rtnl_unicast(reply_skb, net, portid); out: - dev_put(netdev); return ret; }