netlink: Use rhashtable walk iterator
This patch gets rid of the manual rhashtable walk in netlink
which touches rhashtable internals that should not be exposed.
It does so by using the rhashtable iterator primitives.
In fact the existing code was very buggy. Some sockets weren't
shown at all while others were shown more than once.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index a36777b..1558548 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2886,99 +2886,97 @@
#ifdef CONFIG_PROC_FS
struct nl_seq_iter {
struct seq_net_private p;
+ struct rhashtable_iter hti;
int link;
- int hash_idx;
};
-static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
+static int netlink_walk_start(struct nl_seq_iter *iter)
{
- struct nl_seq_iter *iter = seq->private;
- int i, j;
- struct netlink_sock *nlk;
- struct sock *s;
- loff_t off = 0;
+ int err;
- for (i = 0; i < MAX_LINKS; i++) {
- struct rhashtable *ht = &nl_table[i].hash;
- const struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
-
- for (j = 0; j < tbl->size; j++) {
- struct rhash_head *node;
-
- rht_for_each_entry_rcu(nlk, node, tbl, j, node) {
- s = (struct sock *)nlk;
-
- if (sock_net(s) != seq_file_net(seq))
- continue;
- if (off == pos) {
- iter->link = i;
- iter->hash_idx = j;
- return s;
- }
- ++off;
- }
- }
+ err = rhashtable_walk_init(&nl_table[iter->link].hash, &iter->hti);
+ if (err) {
+ iter->link = MAX_LINKS;
+ return err;
}
- return NULL;
+
+ err = rhashtable_walk_start(&iter->hti);
+ return err == -EAGAIN ? 0 : err;
}
-static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
- __acquires(RCU)
+static void netlink_walk_stop(struct nl_seq_iter *iter)
{
- rcu_read_lock();
- return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
+ rhashtable_walk_stop(&iter->hti);
+ rhashtable_walk_exit(&iter->hti);
+}
+
+static void *__netlink_seq_next(struct seq_file *seq)
+{
+ struct nl_seq_iter *iter = seq->private;
+ struct netlink_sock *nlk;
+
+ do {
+ for (;;) {
+ int err;
+
+ nlk = rhashtable_walk_next(&iter->hti);
+
+ if (IS_ERR(nlk)) {
+ if (PTR_ERR(nlk) == -EAGAIN)
+ continue;
+
+ return nlk;
+ }
+
+ if (nlk)
+ break;
+
+ netlink_walk_stop(iter);
+ if (++iter->link >= MAX_LINKS)
+ return NULL;
+
+ err = netlink_walk_start(iter);
+ if (err)
+ return ERR_PTR(err);
+ }
+ } while (sock_net(&nlk->sk) != seq_file_net(seq));
+
+ return nlk;
+}
+
+static void *netlink_seq_start(struct seq_file *seq, loff_t *posp)
+{
+ struct nl_seq_iter *iter = seq->private;
+ void *obj = SEQ_START_TOKEN;
+ loff_t pos;
+ int err;
+
+ iter->link = 0;
+
+ err = netlink_walk_start(iter);
+ if (err)
+ return ERR_PTR(err);
+
+ for (pos = *posp; pos && obj && !IS_ERR(obj); pos--)
+ obj = __netlink_seq_next(seq);
+
+ return obj;
}
static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
- struct rhashtable *ht;
- const struct bucket_table *tbl;
- struct rhash_head *node;
- struct netlink_sock *nlk;
- struct nl_seq_iter *iter;
- struct net *net;
- int i, j;
-
++*pos;
-
- if (v == SEQ_START_TOKEN)
- return netlink_seq_socket_idx(seq, 0);
-
- net = seq_file_net(seq);
- iter = seq->private;
- nlk = v;
-
- i = iter->link;
- ht = &nl_table[i].hash;
- tbl = rht_dereference_rcu(ht->tbl, ht);
- rht_for_each_entry_rcu_continue(nlk, node, nlk->node.next, tbl, iter->hash_idx, node)
- if (net_eq(sock_net((struct sock *)nlk), net))
- return nlk;
-
- j = iter->hash_idx + 1;
-
- do {
-
- for (; j < tbl->size; j++) {
- rht_for_each_entry_rcu(nlk, node, tbl, j, node) {
- if (net_eq(sock_net((struct sock *)nlk), net)) {
- iter->link = i;
- iter->hash_idx = j;
- return nlk;
- }
- }
- }
-
- j = 0;
- } while (++i < MAX_LINKS);
-
- return NULL;
+ return __netlink_seq_next(seq);
}
static void netlink_seq_stop(struct seq_file *seq, void *v)
- __releases(RCU)
{
- rcu_read_unlock();
+ struct nl_seq_iter *iter = seq->private;
+
+ if (iter->link >= MAX_LINKS)
+ return;
+
+ netlink_walk_stop(iter);
}