[IPV4]: Replace __in_dev_get with __in_dev_get_rcu/rtnl
The following patch renames __in_dev_get() to __in_dev_get_rtnl() and
introduces __in_dev_get_rcu() to cover the second case.
1) RCU with refcnt should use in_dev_get().
2) RCU without refcnt should use __in_dev_get_rcu().
3) All others must hold RTNL and use __in_dev_get_rtnl().
There is one exception in net/ipv4/route.c which is in fact a pre-existing
race condition. I've marked it as such so that we remember to fix it.
This patch is based on suggestions and prior work by Suzanne Wood and
Paul McKenney.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 8549f26..381dd6a 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2128,7 +2128,7 @@
struct in_device *in_dev;
rcu_read_lock();
- if ((in_dev = __in_dev_get(dev)) != NULL) {
+ if ((in_dev = __in_dev_get_rcu(dev)) != NULL) {
int our = ip_check_mc(in_dev, daddr, saddr,
skb->nh.iph->protocol);
if (our
@@ -2443,7 +2443,9 @@
err = -ENODEV;
if (dev_out == NULL)
goto out;
- if (__in_dev_get(dev_out) == NULL) {
+
+ /* RACE: Check return value of inet_select_addr instead. */
+ if (__in_dev_get_rtnl(dev_out) == NULL) {
dev_put(dev_out);
goto out; /* Wrong error code */
}