fib_trie: Push rcu_read_lock/unlock to callers
This change is to start cleaning up some of the rcu_read_lock/unlock
handling. I realized while reviewing the code there are several spots that
I don't believe are being handled correctly or are masking warnings by
locally calling rcu_read_lock/unlock instead of calling them at the correct
level.
A common example is a call to fib_get_table followed by fib_table_lookup.
The rcu_read_lock/unlock ought to wrap both but there are several spots where
they were not wrapped.
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 6689020..57be71d 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -109,6 +109,7 @@
return tb;
}
+/* caller must hold either rtnl or rcu read lock */
struct fib_table *fib_get_table(struct net *net, u32 id)
{
struct fib_table *tb;
@@ -119,15 +120,11 @@
id = RT_TABLE_MAIN;
h = id & (FIB_TABLE_HASHSZ - 1);
- rcu_read_lock();
head = &net->ipv4.fib_table_hash[h];
hlist_for_each_entry_rcu(tb, head, tb_hlist) {
- if (tb->tb_id == id) {
- rcu_read_unlock();
+ if (tb->tb_id == id)
return tb;
- }
}
- rcu_read_unlock();
return NULL;
}
#endif /* CONFIG_IP_MULTIPLE_TABLES */
@@ -167,16 +164,18 @@
if (ipv4_is_multicast(addr))
return RTN_MULTICAST;
+ rcu_read_lock();
+
local_table = fib_get_table(net, RT_TABLE_LOCAL);
if (local_table) {
ret = RTN_UNICAST;
- rcu_read_lock();
if (!fib_table_lookup(local_table, &fl4, &res, FIB_LOOKUP_NOREF)) {
if (!dev || dev == res.fi->fib_dev)
ret = res.type;
}
- rcu_read_unlock();
}
+
+ rcu_read_unlock();
return ret;
}
@@ -919,7 +918,7 @@
#undef BRD1_OK
}
-static void nl_fib_lookup(struct fib_result_nl *frn, struct fib_table *tb)
+static void nl_fib_lookup(struct net *net, struct fib_result_nl *frn)
{
struct fib_result res;
@@ -929,6 +928,11 @@
.flowi4_tos = frn->fl_tos,
.flowi4_scope = frn->fl_scope,
};
+ struct fib_table *tb;
+
+ rcu_read_lock();
+
+ tb = fib_get_table(net, frn->tb_id_in);
frn->err = -ENOENT;
if (tb) {
@@ -945,6 +949,8 @@
}
local_bh_enable();
}
+
+ rcu_read_unlock();
}
static void nl_fib_input(struct sk_buff *skb)
@@ -952,7 +958,6 @@
struct net *net;
struct fib_result_nl *frn;
struct nlmsghdr *nlh;
- struct fib_table *tb;
u32 portid;
net = sock_net(skb->sk);
@@ -967,9 +972,7 @@
nlh = nlmsg_hdr(skb);
frn = (struct fib_result_nl *) nlmsg_data(nlh);
- tb = fib_get_table(net, frn->tb_id_in);
-
- nl_fib_lookup(frn, tb);
+ nl_fib_lookup(net, frn);
portid = NETLINK_CB(skb).portid; /* netlink portid */
NETLINK_CB(skb).portid = 0; /* from kernel */