[PATCH RFC net-next 3/7] net/ipv4: Move call_fib_entry_notifiers up for new routes
From: David Ahern <hidden>
Date: 2018-03-22 22:58:16
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
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 <redacted> --- 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 62243a8abf92..d0f70a16f8de 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:
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2.11.0