proc: consolidate per-net single_open callers

There are already 7 of them - time to kill some duplicate code.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

fs/proc/proc_net.c

@@ -51,6 +51,30 @@ int seq_open_net(struct inode *ino, struct file *f,
 }
 EXPORT_SYMBOL_GPL(seq_open_net);
 
+int single_open_net(struct inode *inode, struct file *file,
+		int (*show)(struct seq_file *, void *))
+{
+	int err;
+	struct net *net;
+
+	err = -ENXIO;
+	net = get_proc_net(inode);
+	if (net == NULL)
+		goto err_net;
+
+	err = single_open(file, show, net);
+	if (err < 0)
+		goto err_open;
+
+	return 0;
+
+err_open:
+	put_net(net);
+err_net:
+	return err;
+}
+EXPORT_SYMBOL_GPL(single_open_net);
+
 int seq_release_net(struct inode *ino, struct file *f)
 {
 	struct seq_file *seq;

include/linux/seq_file_net.h

@@ -14,6 +14,8 @@ struct seq_net_private {
 
 int seq_open_net(struct inode *, struct file *,
 		 const struct seq_operations *, int);
+int single_open_net(struct inode *, struct file *file,
+		int (*show)(struct seq_file *, void *));
 int seq_release_net(struct inode *, struct file *);
 static inline struct net *seq_file_net(struct seq_file *seq)
 {

net/ipv4/fib_trie.c

@@ -2251,18 +2251,7 @@ static int fib_triestat_seq_show(struct seq_file *seq, void *v)
 
 static int fib_triestat_seq_open(struct inode *inode, struct file *file)
 {
-	int err;
-	struct net *net;
-
-	net = get_proc_net(inode);
-	if (net == NULL)
-		return -ENXIO;
-	err = single_open(file, fib_triestat_seq_show, net);
-	if (err < 0) {
-		put_net(net);
-		return err;
-	}
-	return 0;
+	return single_open_net(inode, file, fib_triestat_seq_show);
 }
 
 static int fib_triestat_seq_release(struct inode *ino, struct file *f)

net/ipv4/proc.c

@@ -71,24 +71,7 @@ static int sockstat_seq_show(struct seq_file *seq, void *v)
 
 static int sockstat_seq_open(struct inode *inode, struct file *file)
 {
-	int err;
-	struct net *net;
-
-	err = -ENXIO;
-	net = get_proc_net(inode);
-	if (net == NULL)
-		goto err_net;
-
-	err = single_open(file, sockstat_seq_show, net);
-	if (err < 0)
-		goto err_open;
-
-	return 0;
-
-err_open:
-	put_net(net);
-err_net:
-	return err;
+	return single_open_net(inode, file, sockstat_seq_show);
 }
 
 static int sockstat_seq_release(struct inode *inode, struct file *file)
@@ -397,24 +380,7 @@ static int snmp_seq_show(struct seq_file *seq, void *v)
 
 static int snmp_seq_open(struct inode *inode, struct file *file)
 {
-	int err;
-	struct net *net;
-
-	err = -ENXIO;
-	net = get_proc_net(inode);
-	if (net == NULL)
-		goto err_net;
-
-	err = single_open(file, snmp_seq_show, net);
-	if (err < 0)
-		goto err_open;
-
-	return 0;
-
-err_open:
-	put_net(net);
-err_net:
-	return err;
+	return single_open_net(inode, file, snmp_seq_show);
 }
 
 static int snmp_seq_release(struct inode *inode, struct file *file)
@@ -469,24 +435,7 @@ static int netstat_seq_show(struct seq_file *seq, void *v)
 
 static int netstat_seq_open(struct inode *inode, struct file *file)
 {
-	int err;
-	struct net *net;
-
-	err = -ENXIO;
-	net = get_proc_net(inode);
-	if (net == NULL)
-		goto err_net;
-
-	err = single_open(file, netstat_seq_show, net);
-	if (err < 0)
-		goto err_open;
-
-	return 0;
-
-err_open:
-	put_net(net);
-err_net:
-	return err;
+	return single_open_net(inode, file, netstat_seq_show);
 }
 
 static int netstat_seq_release(struct inode *inode, struct file *file)

net/ipv6/proc.c

@@ -183,24 +183,7 @@ static int snmp6_seq_show(struct seq_file *seq, void *v)
 
 static int sockstat6_seq_open(struct inode *inode, struct file *file)
 {
-	int err;
-	struct net *net;
-
-	err = -ENXIO;
-	net = get_proc_net(inode);
-	if (net == NULL)
-		goto err_net;
-
-	err = single_open(file, sockstat6_seq_show, net);
-	if (err < 0)
-		goto err_open;
-
-	return 0;
-
-err_open:
-	put_net(net);
-err_net:
-	return err;
+	return single_open_net(inode, file, sockstat6_seq_show);
 }
 
 static int sockstat6_seq_release(struct inode *inode, struct file *file)

net/ipv6/route.c

@@ -2416,18 +2416,7 @@ static int ipv6_route_show(struct seq_file *m, void *v)
 
 static int ipv6_route_open(struct inode *inode, struct file *file)
 {
-	int err;
-	struct net *net = get_proc_net(inode);
-	if (!net)
-		return -ENXIO;
-
-	err = single_open(file, ipv6_route_show, net);
-	if (err < 0) {
-		put_net(net);
-		return err;
-	}
-
-	return 0;
+	return single_open_net(inode, file, ipv6_route_show);
 }
 
 static int ipv6_route_release(struct inode *inode, struct file *file)
@@ -2463,18 +2452,7 @@ static int rt6_stats_seq_show(struct seq_file *seq, void *v)
 
 static int rt6_stats_seq_open(struct inode *inode, struct file *file)
 {
-	int err;
-	struct net *net = get_proc_net(inode);
-	if (!net)
-		return -ENXIO;
-
-	err = single_open(file, rt6_stats_seq_show, net);
-	if (err < 0) {
-		put_net(net);
-		return err;
-	}
-
-	return 0;
+	return single_open_net(inode, file, rt6_stats_seq_show);
 }
 
 static int rt6_stats_seq_release(struct inode *inode, struct file *file)