linux-kernel - [PATCH 1/9] ipv4: streamline ipmr_new

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Message-Id: <20200519130319.1464195-2-hch@lst.de>
Date:   Tue, 19 May 2020 15:03:11 +0200
From:   Christoph Hellwig <hch@....de>
To:     "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
Cc:     Alexey Kuznetsov <kuznet@....inr.ac.ru>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
        Steffen Klassert <steffen.klassert@...unet.com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/9] ipv4: streamline ipmr_new_tunnel

Reduce a few level of indentation to simplify the function.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 net/ipv4/ipmr.c | 73 ++++++++++++++++++++++++-------------------------
 1 file changed, 36 insertions(+), 37 deletions(-)

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 5c218db2dede7..a1169b6941134 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -471,50 +471,49 @@ static bool ipmr_init_vif_indev(const struct net_device *dev)
 
 static struct net_device *ipmr_new_tunnel(struct net *net, struct vifctl *v)
 {
-	struct net_device  *dev;
+	struct net_device *tunnel_dev, *new_dev;
+	struct ip_tunnel_parm p = { };
+	mm_segment_t oldfs = get_fs();
+	struct ifreq ifr;
+	int err;
 
-	dev = __dev_get_by_name(net, "tunl0");
+	tunnel_dev = __dev_get_by_name(net, "tunl0");
+	if (!tunnel_dev)
+		goto out;
 
-	if (dev) {
-		const struct net_device_ops *ops = dev->netdev_ops;
-		int err;
-		struct ifreq ifr;
-		struct ip_tunnel_parm p;
+	p.iph.daddr = v->vifc_rmt_addr.s_addr;
+	p.iph.saddr = v->vifc_lcl_addr.s_addr;
+	p.iph.version = 4;
+	p.iph.ihl = 5;
+	p.iph.protocol = IPPROTO_IPIP;
+	sprintf(p.name, "dvmrp%d", v->vifc_vifi);
+	ifr.ifr_ifru.ifru_data = (__force void __user *)&p;
 
-		memset(&p, 0, sizeof(p));
-		p.iph.daddr = v->vifc_rmt_addr.s_addr;
-		p.iph.saddr = v->vifc_lcl_addr.s_addr;
-		p.iph.version = 4;
-		p.iph.ihl = 5;
-		p.iph.protocol = IPPROTO_IPIP;
-		sprintf(p.name, "dvmrp%d", v->vifc_vifi);
-		ifr.ifr_ifru.ifru_data = (__force void __user *)&p;
+	if (!tunnel_dev->netdev_ops->ndo_do_ioctl)
+		goto out;
 
-		if (ops->ndo_do_ioctl) {
-			mm_segment_t oldfs = get_fs();
+	set_fs(KERNEL_DS);
+	err = tunnel_dev->netdev_ops->ndo_do_ioctl(tunnel_dev, &ifr,
+			SIOCADDTUNNEL);
+	set_fs(oldfs);
+	if (err)
+		goto out;
 
-			set_fs(KERNEL_DS);
-			err = ops->ndo_do_ioctl(dev, &ifr, SIOCADDTUNNEL);
-			set_fs(oldfs);
-		} else {
-			err = -EOPNOTSUPP;
-		}
-		dev = NULL;
+	new_dev = __dev_get_by_name(net, p.name);
+	if (!new_dev)
+		goto out;
 
-		if (err == 0 &&
-		    (dev = __dev_get_by_name(net, p.name)) != NULL) {
-			dev->flags |= IFF_MULTICAST;
-			if (!ipmr_init_vif_indev(dev))
-				goto failure;
-			if (dev_open(dev, NULL))
-				goto failure;
-			dev_hold(dev);
-		}
-	}
-	return dev;
+	new_dev->flags |= IFF_MULTICAST;
+	if (!ipmr_init_vif_indev(new_dev))
+		goto out_unregister;
+	if (dev_open(new_dev, NULL))
+		goto out_unregister;
+	dev_hold(new_dev);
+	return new_dev;
 
-failure:
-	unregister_netdevice(dev);
+out_unregister:
+	unregister_netdevice(new_dev);
+out:
 	return NULL;
 }
 
-- 
2.26.2