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>
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 5bec666..05ffa54 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -1529,25 +1529,6 @@
fib6_walk(&c.w);
}
-void fib6_clean_all_ro(struct net *net, int (*func)(struct rt6_info *, void *arg),
- int prune, void *arg)
-{
- struct fib6_table *table;
- struct hlist_head *head;
- unsigned int h;
-
- rcu_read_lock();
- for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
- head = &net->ipv6.fib_table_hash[h];
- hlist_for_each_entry_rcu(table, head, tb6_hlist) {
- read_lock_bh(&table->tb6_lock);
- fib6_clean_tree(net, &table->tb6_root,
- func, prune, arg);
- read_unlock_bh(&table->tb6_lock);
- }
- }
- rcu_read_unlock();
-}
void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
int prune, void *arg)
{
@@ -1782,3 +1763,175 @@
unregister_pernet_subsys(&fib6_net_ops);
kmem_cache_destroy(fib6_node_kmem);
}
+
+#ifdef CONFIG_PROC_FS
+
+struct ipv6_route_iter {
+ struct seq_net_private p;
+ struct fib6_walker_t w;
+ loff_t skip;
+ struct fib6_table *tbl;
+};
+
+static int ipv6_route_seq_show(struct seq_file *seq, void *v)
+{
+ struct rt6_info *rt = v;
+ struct ipv6_route_iter *iter = seq->private;
+
+ seq_printf(seq, "%pi6 %02x ", &rt->rt6i_dst.addr, rt->rt6i_dst.plen);
+
+#ifdef CONFIG_IPV6_SUBTREES
+ seq_printf(seq, "%pi6 %02x ", &rt->rt6i_src.addr, rt->rt6i_src.plen);
+#else
+ seq_puts(seq, "00000000000000000000000000000000 00 ");
+#endif
+ if (rt->rt6i_flags & RTF_GATEWAY)
+ seq_printf(seq, "%pi6", &rt->rt6i_gateway);
+ else
+ seq_puts(seq, "00000000000000000000000000000000");
+
+ seq_printf(seq, " %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 : "");
+ iter->w.leaf = NULL;
+ return 0;
+}
+
+static int ipv6_route_yield(struct fib6_walker_t *w)
+{
+ struct ipv6_route_iter *iter = w->args;
+
+ if (!iter->skip)
+ return 1;
+
+ do {
+ iter->w.leaf = iter->w.leaf->dst.rt6_next;
+ iter->skip--;
+ if (!iter->skip && iter->w.leaf)
+ return 1;
+ } while (iter->w.leaf);
+
+ return 0;
+}
+
+static void ipv6_route_seq_setup_walk(struct ipv6_route_iter *iter)
+{
+ memset(&iter->w, 0, sizeof(iter->w));
+ iter->w.func = ipv6_route_yield;
+ iter->w.root = &iter->tbl->tb6_root;
+ iter->w.state = FWS_INIT;
+ iter->w.node = iter->w.root;
+ iter->w.args = iter;
+ INIT_LIST_HEAD(&iter->w.lh);
+ fib6_walker_link(&iter->w);
+}
+
+static struct fib6_table *ipv6_route_seq_next_table(struct fib6_table *tbl,
+ struct net *net)
+{
+ unsigned int h;
+ struct hlist_node *node;
+
+ if (tbl) {
+ h = (tbl->tb6_id & (FIB6_TABLE_HASHSZ - 1)) + 1;
+ node = rcu_dereference_bh(hlist_next_rcu(&tbl->tb6_hlist));
+ } else {
+ h = 0;
+ node = NULL;
+ }
+
+ while (!node && h < FIB6_TABLE_HASHSZ) {
+ node = rcu_dereference_bh(
+ hlist_first_rcu(&net->ipv6.fib_table_hash[h++]));
+ }
+ return hlist_entry_safe(node, struct fib6_table, tb6_hlist);
+}
+
+static void *ipv6_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ int r;
+ struct rt6_info *n;
+ struct net *net = seq_file_net(seq);
+ struct ipv6_route_iter *iter = seq->private;
+
+ if (!v)
+ goto iter_table;
+
+ n = ((struct rt6_info *)v)->dst.rt6_next;
+ if (n) {
+ ++*pos;
+ return n;
+ }
+
+iter_table:
+ read_lock(&iter->tbl->tb6_lock);
+ r = fib6_walk_continue(&iter->w);
+ read_unlock(&iter->tbl->tb6_lock);
+ if (r > 0) {
+ if (v)
+ ++*pos;
+ return iter->w.leaf;
+ } else if (r < 0) {
+ fib6_walker_unlink(&iter->w);
+ return NULL;
+ }
+ fib6_walker_unlink(&iter->w);
+
+ iter->tbl = ipv6_route_seq_next_table(iter->tbl, net);
+ if (!iter->tbl)
+ return NULL;
+
+ ipv6_route_seq_setup_walk(iter);
+ goto iter_table;
+}
+
+static void *ipv6_route_seq_start(struct seq_file *seq, loff_t *pos)
+ __acquires(RCU_BH)
+{
+ struct net *net = seq_file_net(seq);
+ struct ipv6_route_iter *iter = seq->private;
+
+ rcu_read_lock_bh();
+ iter->tbl = ipv6_route_seq_next_table(NULL, net);
+ iter->skip = *pos;
+
+ if (iter->tbl) {
+ ipv6_route_seq_setup_walk(iter);
+ return ipv6_route_seq_next(seq, NULL, pos);
+ } else {
+ return NULL;
+ }
+}
+
+static bool ipv6_route_iter_active(struct ipv6_route_iter *iter)
+{
+ struct fib6_walker_t *w = &iter->w;
+ return w->node && !(w->state == FWS_U && w->node == w->root);
+}
+
+static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
+ __releases(RCU_BH)
+{
+ struct ipv6_route_iter *iter = seq->private;
+
+ if (ipv6_route_iter_active(iter))
+ fib6_walker_unlink(&iter->w);
+
+ rcu_read_unlock_bh();
+}
+
+static const struct seq_operations ipv6_route_seq_ops = {
+ .start = ipv6_route_seq_start,
+ .next = ipv6_route_seq_next,
+ .stop = ipv6_route_seq_stop,
+ .show = ipv6_route_seq_show
+};
+
+int ipv6_route_open(struct inode *inode, struct file *file)
+{
+ return seq_open_net(inode, file, &ipv6_route_seq_ops,
+ sizeof(struct ipv6_route_iter));
+}
+
+#endif /* CONFIG_PROC_FS */