ipv6: avoid high order memory allocations for /proc/net/ipv6_route

Dumping routes on a system with lots rt6_infos in the fibs causes up to
11-order allocations in seq_file (which fail). While we could switch
there to vmalloc we could just implement the streaming interface for
/proc/net/ipv6_route. This patch switches /proc/net/ipv6_route from
single_open_net to seq_open_net.

loff_t *pos tracks dst entries.

Also kill never used struct rt6_proc_arg and now unused function
fib6_clean_all_ro.

Cc: Ben Greear <greearb@candelatech.com>
Cc: Patrick McHardy <kaber@trash.net>
Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 45 deletions

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index c979dd96d82a..aa901bb60cf2 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2800,56 +2800,12 @@ static int ip6_route_dev_notify(struct notifier_block *this,
 
 #ifdef CONFIG_PROC_FS
 
-struct rt6_proc_arg
-{
-	char *buffer;
-	int offset;
-	int length;
-	int skip;
-	int len;
-};
-
-static int rt6_info_route(struct rt6_info *rt, void *p_arg)
-{
-	struct seq_file *m = p_arg;
-
-	seq_printf(m, "%pi6 %02x ", &rt->rt6i_dst.addr, rt->rt6i_dst.plen);
-
-#ifdef CONFIG_IPV6_SUBTREES
-	seq_printf(m, "%pi6 %02x ", &rt->rt6i_src.addr, rt->rt6i_src.plen);
-#else
-	seq_puts(m, "00000000000000000000000000000000 00 ");
-#endif
-	if (rt->rt6i_flags & RTF_GATEWAY) {
-		seq_printf(m, "%pi6", &rt->rt6i_gateway);
-	} else {
-		seq_puts(m, "00000000000000000000000000000000");
-	}
-	seq_printf(m, " %08x %08x %08x %08x %8s\n",
-		   rt->rt6i_metric, atomic_read(&rt->dst.__refcnt),
-		   rt->dst.__use, rt->rt6i_flags,
-		   rt->dst.dev ? rt->dst.dev->name : "");
-	return 0;
-}
-
-static int ipv6_route_show(struct seq_file *m, void *v)
-{
-	struct net *net = (struct net *)m->private;
-	fib6_clean_all_ro(net, rt6_info_route, 0, m);
-	return 0;
-}
-
-static int ipv6_route_open(struct inode *inode, struct file *file)
-{
-	return single_open_net(inode, file, ipv6_route_show);
-}
-
 static const struct file_operations ipv6_route_proc_fops = {
 	.owner		= THIS_MODULE,
 	.open		= ipv6_route_open,
 	.read		= seq_read,
 	.llseek		= seq_lseek,
-	.release	= single_release_net,
+	.release	= seq_release_net,
 };
 
 static int rt6_stats_seq_show(struct seq_file *seq, void *v)