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net/ipv4: Move call_fib_entry_notifiers up for new routes 

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 <dsa@cumulusnetworks.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Ahern 2018-03-27 18:21:57 -07:00 committed by David S. Miller
parent 9776d32537
commit 6635f311ea
1 changed files with 16 additions and 2 deletions
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18
net/ipv4/fib_trie.c
View File

@ -1065,6 +1065,9 @@ noleaf:
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: