From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ying Xue 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> References: <1389685269-18600-1-git-send-email-ying.xue@windriver.com> Mime-Version: 1.0 Content-Type: text/plain Cc: , , , , , , , , To: Return-path: In-Reply-To: <1389685269-18600-1-git-send-email-ying.xue@windriver.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: 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; } -- 1.7.9.5