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authorWANG Cong <xiyou.wangcong@gmail.com>2017-04-28 20:04:29 +0300
committerDavid S. Miller <davem@davemloft.net>2017-05-01 05:44:04 +0300
commitba3f571d5dde27fc4ae83aabe2c06ff08087af49 (patch)
tree27f69a0cce85e6e464684e0660809cf7fc4964be /net/ipv4
parent5010e948420ea1cff85f6c2f64ec7a011aea3d07 (diff)
downloadlinux-ba3f571d5dde27fc4ae83aabe2c06ff08087af49.tar.xz
ipv4: get rid of ip_ra_lock
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. As Eric points out, BH does not need to disable either, RCU readers don't care. Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/ip_sockglue.c12
1 files changed, 2 insertions, 10 deletions
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 1d46d05efb0f..ec4fe3d4b5c9 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 +351,17 @@ 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);
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);
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);
if (ra->destructor)
ra->destructor(sk);
@@ -380,17 +375,14 @@ int ip_ra_control(struct sock *sk, unsigned char on,
return 0;
}
}
- if (!new_ra) {
- spin_unlock_bh(&ip_ra_lock);
+ if (!new_ra)
return -ENOBUFS;
- }
new_ra->sk = sk;
new_ra->destructor = destructor;
RCU_INIT_POINTER(new_ra->next, ra);
rcu_assign_pointer(*rap, new_ra);
sock_hold(sk);
- spin_unlock_bh(&ip_ra_lock);
return 0;
}