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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>
This commit is contained in:
Priyanka Jain 2012-08-12 21:22:29 +00:00 committed by David S. Miller
parent c12b395a46
commit 418a99ac6a
1 changed files with 21 additions and 18 deletions
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39
net/xfrm/xfrm_policy.c
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@ -42,13 +42,14 @@ static DEFINE_SPINLOCK(xfrm_policy_sk_bundle_lock);
static struct dst_entry *xfrm_policy_sk_bundles; static struct dst_entry *xfrm_policy_sk_bundles;
static DEFINE_RWLOCK(xfrm_policy_lock); static DEFINE_RWLOCK(xfrm_policy_lock);
static DEFINE_RWLOCK(xfrm_policy_afinfo_lock); static DEFINE_SPINLOCK(xfrm_policy_afinfo_lock);
static struct xfrm_policy_afinfo *xfrm_policy_afinfo[NPROTO]; static struct xfrm_policy_afinfo __rcu *xfrm_policy_afinfo[NPROTO]
__read_mostly;
static struct kmem_cache *xfrm_dst_cache __read_mostly; static struct kmem_cache *xfrm_dst_cache __read_mostly;
static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family); 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 void xfrm_init_pmtu(struct dst_entry *dst);
static int stale_bundle(struct dst_entry *dst); static int stale_bundle(struct dst_entry *dst);
static int xfrm_bundle_ok(struct xfrm_dst *xdst); 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; return -EINVAL;
if (unlikely(afinfo->family >= NPROTO)) if (unlikely(afinfo->family >= NPROTO))
return -EAFNOSUPPORT; return -EAFNOSUPPORT;
write_lock_bh(&xfrm_policy_afinfo_lock); spin_lock_bh(&xfrm_policy_afinfo_lock);
if (unlikely(xfrm_policy_afinfo[afinfo->family] != NULL)) if (unlikely(xfrm_policy_afinfo[afinfo->family] != NULL))
err = -ENOBUFS; err = -ENOBUFS;
else { else {
@ -2439,9 +2440,9 @@ int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo)
dst_ops->neigh_lookup = xfrm_neigh_lookup; dst_ops->neigh_lookup = xfrm_neigh_lookup;
if (likely(afinfo->garbage_collect == NULL)) if (likely(afinfo->garbage_collect == NULL))
afinfo->garbage_collect = xfrm_garbage_collect_deferred; 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(); rtnl_lock();
for_each_net(net) { for_each_net(net) {
@ -2474,13 +2475,14 @@ int xfrm_policy_unregister_afinfo(struct xfrm_policy_afinfo *afinfo)
return -EINVAL; return -EINVAL;
if (unlikely(afinfo->family >= NPROTO)) if (unlikely(afinfo->family >= NPROTO))
return -EAFNOSUPPORT; 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 (likely(xfrm_policy_afinfo[afinfo->family] != NULL)) {
if (unlikely(xfrm_policy_afinfo[afinfo->family] != afinfo)) if (unlikely(xfrm_policy_afinfo[afinfo->family] != afinfo))
err = -EINVAL; err = -EINVAL;
else { else {
struct dst_ops *dst_ops = afinfo->dst_ops; 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->kmem_cachep = NULL;
dst_ops->check = NULL; dst_ops->check = NULL;
dst_ops->negative_advice = NULL; dst_ops->negative_advice = NULL;
@ -2488,7 +2490,8 @@ int xfrm_policy_unregister_afinfo(struct xfrm_policy_afinfo *afinfo)
afinfo->garbage_collect = NULL; afinfo->garbage_collect = NULL;
} }
} }
write_unlock_bh(&xfrm_policy_afinfo_lock); spin_unlock_bh(&xfrm_policy_afinfo_lock);
synchronize_rcu();
return err; return err;
} }
EXPORT_SYMBOL(xfrm_policy_unregister_afinfo); 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; struct xfrm_policy_afinfo *afinfo;
read_lock_bh(&xfrm_policy_afinfo_lock); rcu_read_lock_bh();
afinfo = xfrm_policy_afinfo[AF_INET]; afinfo = rcu_dereference(xfrm_policy_afinfo[AF_INET]);
if (afinfo) if (afinfo)
net->xfrm.xfrm4_dst_ops = *afinfo->dst_ops; net->xfrm.xfrm4_dst_ops = *afinfo->dst_ops;
#if IS_ENABLED(CONFIG_IPV6) #if IS_ENABLED(CONFIG_IPV6)
afinfo = xfrm_policy_afinfo[AF_INET6]; afinfo = rcu_dereference(xfrm_policy_afinfo[AF_INET6]);
if (afinfo) if (afinfo)
net->xfrm.xfrm6_dst_ops = *afinfo->dst_ops; net->xfrm.xfrm6_dst_ops = *afinfo->dst_ops;
#endif #endif
read_unlock_bh(&xfrm_policy_afinfo_lock); rcu_read_unlock_bh();
} }
static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family) 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; struct xfrm_policy_afinfo *afinfo;
if (unlikely(family >= NPROTO)) if (unlikely(family >= NPROTO))
return NULL; return NULL;
read_lock(&xfrm_policy_afinfo_lock); rcu_read_lock();
afinfo = xfrm_policy_afinfo[family]; afinfo = rcu_dereference(xfrm_policy_afinfo[family]);
if (unlikely(!afinfo)) if (unlikely(!afinfo))
read_unlock(&xfrm_policy_afinfo_lock); rcu_read_unlock();
return afinfo; 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) static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)