diff options
Diffstat (limited to 'net/ipv4/inetpeer.c')
| -rw-r--r-- | net/ipv4/inetpeer.c | 57 |
1 files changed, 23 insertions, 34 deletions
diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c index 5ab56f4cb529..7b1e0a2d6906 100644 --- a/net/ipv4/inetpeer.c +++ b/net/ipv4/inetpeer.c @@ -60,7 +60,7 @@ void inet_peer_base_init(struct inet_peer_base *bp) seqlock_init(&bp->lock); bp->total = 0; } -EXPORT_SYMBOL_GPL(inet_peer_base_init); +EXPORT_IPV6_MOD_GPL(inet_peer_base_init); #define PEER_MAX_GC 32 @@ -95,6 +95,7 @@ static struct inet_peer *lookup(const struct inetpeer_addr *daddr, { struct rb_node **pp, *parent, *next; struct inet_peer *p; + u32 now; pp = &base->rb_root.rb_node; parent = NULL; @@ -108,8 +109,9 @@ static struct inet_peer *lookup(const struct inetpeer_addr *daddr, p = rb_entry(parent, struct inet_peer, rb_node); cmp = inetpeer_addr_cmp(daddr, &p->daddr); if (cmp == 0) { - if (!refcount_inc_not_zero(&p->refcnt)) - break; + now = jiffies; + if (READ_ONCE(p->dtime) != now) + WRITE_ONCE(p->dtime, now); return p; } if (gc_stack) { @@ -150,9 +152,6 @@ static void inet_peer_gc(struct inet_peer_base *base, for (i = 0; i < gc_cnt; i++) { p = gc_stack[i]; - /* The READ_ONCE() pairs with the WRITE_ONCE() - * in inet_putpeer() - */ delta = (__u32)jiffies - READ_ONCE(p->dtime); if (delta < ttl || !refcount_dec_if_one(&p->refcnt)) @@ -168,31 +167,23 @@ static void inet_peer_gc(struct inet_peer_base *base, } } +/* Must be called under RCU : No refcount change is done here. */ struct inet_peer *inet_getpeer(struct inet_peer_base *base, - const struct inetpeer_addr *daddr, - int create) + const struct inetpeer_addr *daddr) { struct inet_peer *p, *gc_stack[PEER_MAX_GC]; struct rb_node **pp, *parent; unsigned int gc_cnt, seq; - int invalidated; /* Attempt a lockless lookup first. * Because of a concurrent writer, we might not find an existing entry. */ - rcu_read_lock(); seq = read_seqbegin(&base->lock); p = lookup(daddr, base, seq, NULL, &gc_cnt, &parent, &pp); - invalidated = read_seqretry(&base->lock, seq); - rcu_read_unlock(); if (p) return p; - /* If no writer did a change during our lookup, we can return early. */ - if (!create && !invalidated) - return NULL; - /* retry an exact lookup, taking the lock before. * At least, nodes should be hot in our cache. */ @@ -201,12 +192,12 @@ struct inet_peer *inet_getpeer(struct inet_peer_base *base, gc_cnt = 0; p = lookup(daddr, base, seq, gc_stack, &gc_cnt, &parent, &pp); - if (!p && create) { + if (!p) { p = kmem_cache_alloc(peer_cachep, GFP_ATOMIC); if (p) { p->daddr = *daddr; p->dtime = (__u32)jiffies; - refcount_set(&p->refcnt, 2); + refcount_set(&p->refcnt, 1); atomic_set(&p->rid, 0); p->metrics[RTAX_LOCK-1] = INETPEER_METRICS_NEW; p->rate_tokens = 0; @@ -227,19 +218,13 @@ struct inet_peer *inet_getpeer(struct inet_peer_base *base, return p; } -EXPORT_SYMBOL_GPL(inet_getpeer); +EXPORT_IPV6_MOD_GPL(inet_getpeer); void inet_putpeer(struct inet_peer *p) { - /* The WRITE_ONCE() pairs with itself (we run lockless) - * and the READ_ONCE() in inet_peer_gc() - */ - WRITE_ONCE(p->dtime, (__u32)jiffies); - if (refcount_dec_and_test(&p->refcnt)) kfree_rcu(p, rcu); } -EXPORT_SYMBOL_GPL(inet_putpeer); /* * Check transmit rate limitation for given message. @@ -261,26 +246,30 @@ EXPORT_SYMBOL_GPL(inet_putpeer); #define XRLIM_BURST_FACTOR 6 bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout) { - unsigned long now, token; + unsigned long now, token, otoken, delta; bool rc = false; if (!peer) return true; - token = peer->rate_tokens; + token = otoken = READ_ONCE(peer->rate_tokens); now = jiffies; - token += now - peer->rate_last; - peer->rate_last = now; - if (token > XRLIM_BURST_FACTOR * timeout) - token = XRLIM_BURST_FACTOR * timeout; + delta = now - READ_ONCE(peer->rate_last); + if (delta) { + WRITE_ONCE(peer->rate_last, now); + token += delta; + if (token > XRLIM_BURST_FACTOR * timeout) + token = XRLIM_BURST_FACTOR * timeout; + } if (token >= timeout) { token -= timeout; rc = true; } - peer->rate_tokens = token; + if (token != otoken) + WRITE_ONCE(peer->rate_tokens, token); return rc; } -EXPORT_SYMBOL(inet_peer_xrlim_allow); +EXPORT_IPV6_MOD(inet_peer_xrlim_allow); void inetpeer_invalidate_tree(struct inet_peer_base *base) { @@ -297,4 +286,4 @@ void inetpeer_invalidate_tree(struct inet_peer_base *base) base->total = 0; } -EXPORT_SYMBOL(inetpeer_invalidate_tree); +EXPORT_IPV6_MOD(inetpeer_invalidate_tree); |