After commit 1215e51edad1 ("ipv4: fix a deadlock in ip_ra_control")
we always take RTNL lock for ip_ra_control() which is the only place
we update the list ip_ra_chain, so the ip_ra_lock is no longer needed,
we just need to disable BH there.
Signed-off-by: Cong Wang <xiyou.wangc...@gmail.com>
---
net/ipv4/ip_sockglue.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 1d46d05..2923ea1 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -330,7 +330,6 @@ int ip_cmsg_send(struct sock *sk, struct msghdr *msg,
struct ipcm_cookie *ipc,
sent to multicast group to reach destination designated router.
*/
struct ip_ra_chain __rcu *ip_ra_chain;
-static DEFINE_SPINLOCK(ip_ra_lock);
static void ip_ra_destroy_rcu(struct rcu_head *head)
@@ -352,21 +351,21 @@ int ip_ra_control(struct sock *sk, unsigned char on,
new_ra = on ? kmalloc(sizeof(*new_ra), GFP_KERNEL) : NULL;
- spin_lock_bh(&ip_ra_lock);
+ ASSERT_RTNL();
+ local_bh_disable();
for (rap = &ip_ra_chain;
- (ra = rcu_dereference_protected(*rap,
- lockdep_is_held(&ip_ra_lock))) != NULL;
+ (ra = rtnl_dereference(*rap)) != NULL;
rap = &ra->next) {
if (ra->sk == sk) {
if (on) {
- spin_unlock_bh(&ip_ra_lock);
+ local_bh_enable();
kfree(new_ra);
return -EADDRINUSE;
}
/* dont let ip_call_ra_chain() use sk again */
ra->sk = NULL;
RCU_INIT_POINTER(*rap, ra->next);
- spin_unlock_bh(&ip_ra_lock);
+ local_bh_enable();
if (ra->destructor)
ra->destructor(sk);
@@ -381,7 +380,7 @@ int ip_ra_control(struct sock *sk, unsigned char on,
}
}
if (!new_ra) {
- spin_unlock_bh(&ip_ra_lock);
+ local_bh_enable();
return -ENOBUFS;
}
new_ra->sk = sk;
@@ -390,7 +389,7 @@ int ip_ra_control(struct sock *sk, unsigned char on,
RCU_INIT_POINTER(new_ra->next, ra);
rcu_assign_pointer(*rap, new_ra);
sock_hold(sk);
- spin_unlock_bh(&ip_ra_lock);
+ local_bh_enable();
return 0;
}
--
2.5.5
