1 files changed, 8 insertions, 23 deletions

diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c
index 5bd759963451..9c5ffe3b5f77 100644
--- a/net/ipv4/inetpeer.c
+++ b/net/ipv4/inetpeer.c
@@ -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) {
@@ -155,9 +157,6 @@ 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))
@@ -173,31 +172,23 @@ 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.
 	 */
@@ -206,12 +197,12 @@ 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;
@@ -236,15 +227,9 @@ EXPORT_SYMBOL_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))
 		call_rcu(&p->rcu, inetpeer_free_rcu);
 }
-EXPORT_SYMBOL_GPL(inet_putpeer);
 
 /*
  *	Check transmit rate limitation for given message.