The following commit has been merged in the batman-adv/next branch: commit 418a99ac6ad487dc9c42e6b0e85f941af56330f2 Author: Priyanka Jain Priyanka.Jain@freescale.com Date: Sun Aug 12 21:22:29 2012 +0000
Replace rwlock on xfrm_policy_afinfo with rcu
xfrm_policy_afinfo is read mosly data structure. Write on xfrm_policy_afinfo is done only at the time of configuration. So rwlocks can be safely replaced with RCU.
RCUs usage optimizes the performance.
Signed-off-by: Priyanka Jain Priyanka.Jain@freescale.com Signed-off-by: David S. Miller davem@davemloft.net
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index c5a5165..5ad4d2c 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -42,13 +42,14 @@ static DEFINE_SPINLOCK(xfrm_policy_sk_bundle_lock); static struct dst_entry *xfrm_policy_sk_bundles; static DEFINE_RWLOCK(xfrm_policy_lock);
-static DEFINE_RWLOCK(xfrm_policy_afinfo_lock); -static struct xfrm_policy_afinfo *xfrm_policy_afinfo[NPROTO]; +static DEFINE_SPINLOCK(xfrm_policy_afinfo_lock); +static struct xfrm_policy_afinfo __rcu *xfrm_policy_afinfo[NPROTO] + __read_mostly;
static struct kmem_cache *xfrm_dst_cache __read_mostly;
static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family); -static void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo); +static inline void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo); static void xfrm_init_pmtu(struct dst_entry *dst); static int stale_bundle(struct dst_entry *dst); static int xfrm_bundle_ok(struct xfrm_dst *xdst); @@ -2418,7 +2419,7 @@ int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo) return -EINVAL; if (unlikely(afinfo->family >= NPROTO)) return -EAFNOSUPPORT; - write_lock_bh(&xfrm_policy_afinfo_lock); + spin_lock_bh(&xfrm_policy_afinfo_lock); if (unlikely(xfrm_policy_afinfo[afinfo->family] != NULL)) err = -ENOBUFS; else { @@ -2439,9 +2440,9 @@ int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo) dst_ops->neigh_lookup = xfrm_neigh_lookup; if (likely(afinfo->garbage_collect == NULL)) afinfo->garbage_collect = xfrm_garbage_collect_deferred; - xfrm_policy_afinfo[afinfo->family] = afinfo; + rcu_assign_pointer(xfrm_policy_afinfo[afinfo->family], afinfo); } - write_unlock_bh(&xfrm_policy_afinfo_lock); + spin_unlock_bh(&xfrm_policy_afinfo_lock);
rtnl_lock(); for_each_net(net) { @@ -2474,13 +2475,14 @@ int xfrm_policy_unregister_afinfo(struct xfrm_policy_afinfo *afinfo) return -EINVAL; if (unlikely(afinfo->family >= NPROTO)) return -EAFNOSUPPORT; - write_lock_bh(&xfrm_policy_afinfo_lock); + spin_lock_bh(&xfrm_policy_afinfo_lock); if (likely(xfrm_policy_afinfo[afinfo->family] != NULL)) { if (unlikely(xfrm_policy_afinfo[afinfo->family] != afinfo)) err = -EINVAL; else { struct dst_ops *dst_ops = afinfo->dst_ops; - xfrm_policy_afinfo[afinfo->family] = NULL; + rcu_assign_pointer(xfrm_policy_afinfo[afinfo->family], + NULL); dst_ops->kmem_cachep = NULL; dst_ops->check = NULL; dst_ops->negative_advice = NULL; @@ -2488,7 +2490,8 @@ int xfrm_policy_unregister_afinfo(struct xfrm_policy_afinfo *afinfo) afinfo->garbage_collect = NULL; } } - write_unlock_bh(&xfrm_policy_afinfo_lock); + spin_unlock_bh(&xfrm_policy_afinfo_lock); + synchronize_rcu(); return err; } EXPORT_SYMBOL(xfrm_policy_unregister_afinfo); @@ -2497,16 +2500,16 @@ static void __net_init xfrm_dst_ops_init(struct net *net) { struct xfrm_policy_afinfo *afinfo;
- read_lock_bh(&xfrm_policy_afinfo_lock); - afinfo = xfrm_policy_afinfo[AF_INET]; + rcu_read_lock_bh(); + afinfo = rcu_dereference(xfrm_policy_afinfo[AF_INET]); if (afinfo) net->xfrm.xfrm4_dst_ops = *afinfo->dst_ops; #if IS_ENABLED(CONFIG_IPV6) - afinfo = xfrm_policy_afinfo[AF_INET6]; + afinfo = rcu_dereference(xfrm_policy_afinfo[AF_INET6]); if (afinfo) net->xfrm.xfrm6_dst_ops = *afinfo->dst_ops; #endif - read_unlock_bh(&xfrm_policy_afinfo_lock); + rcu_read_unlock_bh(); }
static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family) @@ -2514,16 +2517,16 @@ static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family) struct xfrm_policy_afinfo *afinfo; if (unlikely(family >= NPROTO)) return NULL; - read_lock(&xfrm_policy_afinfo_lock); - afinfo = xfrm_policy_afinfo[family]; + rcu_read_lock(); + afinfo = rcu_dereference(xfrm_policy_afinfo[family]); if (unlikely(!afinfo)) - read_unlock(&xfrm_policy_afinfo_lock); + rcu_read_unlock(); return afinfo; }
-static void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo) +static inline void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo) { - read_unlock(&xfrm_policy_afinfo_lock); + rcu_read_unlock(); }
static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)