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authorTom Herbert <tom@herbertland.com>2018-06-28 00:38:59 +0300
committerDavid S. Miller <davem@davemloft.net>2018-06-29 05:32:55 +0300
commitf7a2ba5ab9c5e7cf9036ec68d3528ccdf9e81b0a (patch)
tree33735ccf0afcebbaf8038e5d5e403ad1f8443ebb /net/ipv6/ila
parent6d268910a4e222184172e3b991d64c94edfa5388 (diff)
downloadlinux-f7a2ba5ab9c5e7cf9036ec68d3528ccdf9e81b0a.tar.xz
ila: Fix use of rhashtable walk in ila_xlat.c
Perform better EAGAIN handling, handle case where ila_dump_info fails and we missed objects in the dump, and add a skip index to skip over ila entires in a list on a rhashtable node that have already been visited (by a previous call to ila_nl_dump). Signed-off-by: Tom Herbert <tom@quantonium.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/ila')
-rw-r--r--net/ipv6/ila/ila_xlat.c70
1 files changed, 54 insertions, 16 deletions
diff --git a/net/ipv6/ila/ila_xlat.c b/net/ipv6/ila/ila_xlat.c
index 10ae13560b40..40f3f640e856 100644
--- a/net/ipv6/ila/ila_xlat.c
+++ b/net/ipv6/ila/ila_xlat.c
@@ -475,24 +475,31 @@ out_free:
struct ila_dump_iter {
struct rhashtable_iter rhiter;
+ int skip;
};
static int ila_nl_dump_start(struct netlink_callback *cb)
{
struct net *net = sock_net(cb->skb->sk);
struct ila_net *ilan = net_generic(net, ila_net_id);
- struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args[0];
+ struct ila_dump_iter *iter;
+ int ret;
- if (!iter) {
- iter = kmalloc(sizeof(*iter), GFP_KERNEL);
- if (!iter)
- return -ENOMEM;
+ iter = kmalloc(sizeof(*iter), GFP_KERNEL);
+ if (!iter)
+ return -ENOMEM;
- cb->args[0] = (long)iter;
+ ret = rhashtable_walk_init(&ilan->rhash_table, &iter->rhiter,
+ GFP_KERNEL);
+ if (ret) {
+ kfree(iter);
+ return ret;
}
- return rhashtable_walk_init(&ilan->rhash_table, &iter->rhiter,
- GFP_KERNEL);
+ iter->skip = 0;
+ cb->args[0] = (long)iter;
+
+ return ret;
}
static int ila_nl_dump_done(struct netlink_callback *cb)
@@ -510,20 +517,45 @@ static int ila_nl_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args[0];
struct rhashtable_iter *rhiter = &iter->rhiter;
+ int skip = iter->skip;
struct ila_map *ila;
int ret;
rhashtable_walk_start(rhiter);
- for (;;) {
- ila = rhashtable_walk_next(rhiter);
+ /* Get first entry */
+ ila = rhashtable_walk_peek(rhiter);
+
+ if (ila && !IS_ERR(ila) && skip) {
+ /* Skip over visited entries */
+
+ while (ila && skip) {
+ /* Skip over any ila entries in this list that we
+ * have already dumped.
+ */
+ ila = rcu_access_pointer(ila->next);
+ skip--;
+ }
+ }
+ skip = 0;
+
+ for (;;) {
if (IS_ERR(ila)) {
- if (PTR_ERR(ila) == -EAGAIN)
- continue;
ret = PTR_ERR(ila);
- goto done;
+ if (ret == -EAGAIN) {
+ /* Table has changed and iter has reset. Return
+ * -EAGAIN to the application even if we have
+ * written data to the skb. The application
+ * needs to deal with this.
+ */
+
+ goto out_ret;
+ } else {
+ break;
+ }
} else if (!ila) {
+ ret = 0;
break;
}
@@ -532,15 +564,21 @@ static int ila_nl_dump(struct sk_buff *skb, struct netlink_callback *cb)
cb->nlh->nlmsg_seq, NLM_F_MULTI,
skb, ILA_CMD_GET);
if (ret)
- goto done;
+ goto out;
+ skip++;
ila = rcu_access_pointer(ila->next);
}
+
+ skip = 0;
+ ila = rhashtable_walk_next(rhiter);
}
- ret = skb->len;
+out:
+ iter->skip = skip;
+ ret = (skb->len ? : ret);
-done:
+out_ret:
rhashtable_walk_stop(rhiter);
return ret;
}