xfrm: replace rwlock on xfrm_km_list with rcu

Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

1 files changed, 30 insertions, 28 deletions

diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 64780a6f7b86..1522f19f273a 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -1644,27 +1644,26 @@ static void xfrm_replay_timer_handler(unsigned long data)
 }
 
 static LIST_HEAD(xfrm_km_list);
-static DEFINE_RWLOCK(xfrm_km_lock);
 
 void km_policy_notify(struct xfrm_policy *xp, int dir, const struct km_event *c)
 {
         struct xfrm_mgr *km;
 
-        read_lock(&xfrm_km_lock);
-        list_for_each_entry(km, &xfrm_km_list, list)
+        rcu_read_lock();
+        list_for_each_entry_rcu(km, &xfrm_km_list, list)
                 if (km->notify_policy)
                         km->notify_policy(xp, dir, c);
-        read_unlock(&xfrm_km_lock);
+        rcu_read_unlock();
 }
 
 void km_state_notify(struct xfrm_state *x, const struct km_event *c)
 {
         struct xfrm_mgr *km;
-        read_lock(&xfrm_km_lock);
-        list_for_each_entry(km, &xfrm_km_list, list)
+        rcu_read_lock();
+        list_for_each_entry_rcu(km, &xfrm_km_list, list)
                 if (km->notify)
                         km->notify(x, c);
-        read_unlock(&xfrm_km_lock);
+        rcu_read_unlock();
 }
 
 EXPORT_SYMBOL(km_policy_notify);
@@ -1694,13 +1693,13 @@ int km_query(struct xfrm_state *x, struct xfrm_tmpl *t, struct xfrm_policy *pol)
         int err = -EINVAL, acqret;
         struct xfrm_mgr *km;
 
-        read_lock(&xfrm_km_lock);
-        list_for_each_entry(km, &xfrm_km_list, list) {
+        rcu_read_lock();
+        list_for_each_entry_rcu(km, &xfrm_km_list, list) {
                 acqret = km->acquire(x, t, pol);
                 if (!acqret)
                         err = acqret;
         }
-        read_unlock(&xfrm_km_lock);
+        rcu_read_unlock();
         return err;
 }
 EXPORT_SYMBOL(km_query);
@@ -1710,14 +1709,14 @@ int km_new_mapping(struct xfrm_state *x, xfrm_address_t *ipaddr, __be16 sport)
         int err = -EINVAL;
         struct xfrm_mgr *km;
 
-        read_lock(&xfrm_km_lock);
-        list_for_each_entry(km, &xfrm_km_list, list) {
+        rcu_read_lock();
+        list_for_each_entry_rcu(km, &xfrm_km_list, list) {
                 if (km->new_mapping)
                         err = km->new_mapping(x, ipaddr, sport);
                 if (!err)
                         break;
         }
-        read_unlock(&xfrm_km_lock);
+        rcu_read_unlock();
         return err;
 }
 EXPORT_SYMBOL(km_new_mapping);
@@ -1746,15 +1745,15 @@ int km_migrate(const struct xfrm_selector *sel, u8 dir, u8 type,
         int ret;
         struct xfrm_mgr *km;
 
-        read_lock(&xfrm_km_lock);
-        list_for_each_entry(km, &xfrm_km_list, list) {
+        rcu_read_lock();
+        list_for_each_entry_rcu(km, &xfrm_km_list, list) {
                 if (km->migrate) {
                         ret = km->migrate(sel, dir, type, m, num_migrate, k);
                         if (!ret)
                                 err = ret;
                 }
         }
-        read_unlock(&xfrm_km_lock);
+        rcu_read_unlock();
         return err;
 }
 EXPORT_SYMBOL(km_migrate);
@@ -1766,15 +1765,15 @@ int km_report(struct net *net, u8 proto, struct xfrm_selector *sel, xfrm_address
         int ret;
         struct xfrm_mgr *km;
 
-        read_lock(&xfrm_km_lock);
-        list_for_each_entry(km, &xfrm_km_list, list) {
+        rcu_read_lock();
+        list_for_each_entry_rcu(km, &xfrm_km_list, list) {
                 if (km->report) {
                         ret = km->report(net, proto, sel, addr);
                         if (!ret)
                                 err = ret;
                 }
         }
-        read_unlock(&xfrm_km_lock);
+        rcu_read_unlock();
         return err;
 }
 EXPORT_SYMBOL(km_report);
@@ -1798,14 +1797,14 @@ int xfrm_user_policy(struct sock *sk, int optname, u8 __user *optval, int optlen
                 goto out;
 
         err = -EINVAL;
-        read_lock(&xfrm_km_lock);
-        list_for_each_entry(km, &xfrm_km_list, list) {
+        rcu_read_lock();
+        list_for_each_entry_rcu(km, &xfrm_km_list, list) {
                 pol = km->compile_policy(sk, optname, data,
                                          optlen, &err);
                 if (err >= 0)
                         break;
         }
-        read_unlock(&xfrm_km_lock);
+        rcu_read_unlock();
 
         if (err >= 0) {
                 xfrm_sk_policy_insert(sk, err, pol);
@@ -1819,20 +1818,23 @@ out:
 }
 EXPORT_SYMBOL(xfrm_user_policy);
 
+static DEFINE_SPINLOCK(xfrm_km_lock);
+
 int xfrm_register_km(struct xfrm_mgr *km)
 {
-        write_lock_bh(&xfrm_km_lock);
-        list_add_tail(&km->list, &xfrm_km_list);
-        write_unlock_bh(&xfrm_km_lock);
+        spin_lock_bh(&xfrm_km_lock);
+        list_add_tail_rcu(&km->list, &xfrm_km_list);
+        spin_unlock_bh(&xfrm_km_lock);
         return 0;
 }
 EXPORT_SYMBOL(xfrm_register_km);
 
 int xfrm_unregister_km(struct xfrm_mgr *km)
 {
-        write_lock_bh(&xfrm_km_lock);
-        list_del(&km->list);
-        write_unlock_bh(&xfrm_km_lock);
+        spin_lock_bh(&xfrm_km_lock);
+        list_del_rcu(&km->list);
+        spin_unlock_bh(&xfrm_km_lock);
+        synchronize_rcu();
         return 0;
 }
 EXPORT_SYMBOL(xfrm_unregister_km);