Move call to call_fib_entry_notifiers for new IPv4 routes to right
before the call to fib_insert_alias. At this point the only remaining
failure path is memory allocations in fib_insert_node. Handle that
very unlikely failure with a call to call_fib_entry_notifiers to
tell drivers about it.
At this point notifier handlers can decide the fate of the new route
with a clean path to delete the potential new entry if the notifier
returns non-0.
Signed-off-by: David Ahern <d...@cumulusnetworks.com>
---
net/ipv4/fib_trie.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index fac0b73e24d1..67116233e2bc 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1065,6 +1065,9 @@ static int fib_insert_node(struct trie *t, struct
key_vector *tp,
return -ENOMEM;
}
+/* fib notifier for ADD is sent before calling fib_insert_alias with
+ * the expectation that the only possible failure ENOMEM
+ */
static int fib_insert_alias(struct trie *t, struct key_vector *tp,
struct key_vector *l, struct fib_alias *new,
struct fib_alias *fa, t_key key)
@@ -1263,21 +1266,32 @@ int fib_table_insert(struct net *net, struct fib_table
*tb,
new_fa->tb_id = tb->tb_id;
new_fa->fa_default = -1;
+ err = call_fib_entry_notifiers(net, event, key, plen, new_fa, extack);
+ if (err)
+ goto out_free_new_fa;
+
/* Insert new entry to the list. */
err = fib_insert_alias(t, tp, l, new_fa, fa, key);
if (err)
- goto out_free_new_fa;
+ goto out_fib_notif;
if (!plen)
tb->tb_num_default++;
rt_cache_flush(cfg->fc_nlinfo.nl_net);
- call_fib_entry_notifiers(net, event, key, plen, new_fa, extack);
rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen, new_fa->tb_id,
&cfg->fc_nlinfo, nlflags);
succeeded:
return 0;
+out_fib_notif:
+ /* notifier was sent that entry would be added to trie, but
+ * the add failed and need to recover. Only failure for
+ * fib_insert_alias is ENOMEM.
+ */
+ NL_SET_ERR_MSG(extack, "Failed to insert route into trie");
+ call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, key,
+ plen, new_fa, NULL);
out_free_new_fa:
kmem_cache_free(fn_alias_kmem, new_fa);
out:
--
2.11.0
