net: Add initial_ref arg to dst_alloc().

This allows avoiding multiple writes to the initial __refcnt.

The most simplest cases of wanting an initial reference of "1"
in ipv4 and ipv6 have been converted, the rest have been left
along and kept at the existing "0".

Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 9 insertions, 13 deletions

diff --git a/net/core/dst.c b/net/core/dst.c
index c1674fde827..91104d35de7 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -166,7 +166,7 @@ EXPORT_SYMBOL(dst_discard);
 
 const u32 dst_default_metrics[RTAX_MAX];
 
-void *dst_alloc(struct dst_ops *ops)
+void *dst_alloc(struct dst_ops *ops, int initial_ref)
 {
 	struct dst_entry *dst;
 
@@ -177,7 +177,7 @@ void *dst_alloc(struct dst_ops *ops)
 	dst = kmem_cache_zalloc(ops->kmem_cachep, GFP_ATOMIC);
 	if (!dst)
 		return NULL;
-	atomic_set(&dst->__refcnt, 0);
+	atomic_set(&dst->__refcnt, initial_ref);
 	dst->ops = ops;
 	dst->lastuse = jiffies;
 	dst->path = dst;
diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c
index 42c9c62d341..06c054d5ccb 100644
--- a/net/decnet/dn_route.c
+++ b/net/decnet/dn_route.c
@@ -1122,7 +1122,7 @@ make_route:
 	if (dev_out->flags & IFF_LOOPBACK)
 		flags |= RTCF_LOCAL;
 
-	rt = dst_alloc(&dn_dst_ops);
+	rt = dst_alloc(&dn_dst_ops, 0);
 	if (rt == NULL)
 		goto e_nobufs;
 
@@ -1383,7 +1383,7 @@ static int dn_route_input_slow(struct sk_buff *skb)
 	}
 
 make_route:
-	rt = dst_alloc(&dn_dst_ops);
+	rt = dst_alloc(&dn_dst_ops, 0);
 	if (rt == NULL)
 		goto e_nobufs;
 
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 79a28718102..9841543c468 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1818,12 +1818,10 @@ static void rt_set_nexthop(struct rtable *rt, struct fib_result *res, u32 itag)
 
 static struct rtable *rt_dst_alloc(bool nopolicy, bool noxfrm)
 {
-	struct rtable *rt = dst_alloc(&ipv4_dst_ops);
+	struct rtable *rt = dst_alloc(&ipv4_dst_ops, 1);
 	if (rt) {
 		rt->dst.obsolete = -1;
 
-		atomic_set(&rt->dst.__refcnt, 1);
-
 		rt->dst.flags = DST_HOST |
 			(nopolicy ? DST_NOPOLICY : 0) |
 			(noxfrm ? DST_NOXFRM : 0);
@@ -2679,12 +2677,11 @@ static int ipv4_dst_blackhole(struct net *net, struct rtable **rp, struct flowi
 {
 	struct rtable *ort = *rp;
 	struct rtable *rt = (struct rtable *)
-		dst_alloc(&ipv4_dst_blackhole_ops);
+		dst_alloc(&ipv4_dst_blackhole_ops, 1);
 
 	if (rt) {
 		struct dst_entry *new = &rt->dst;
 
-		atomic_set(&new->__refcnt, 1);
 		new->__use = 1;
 		new->input = dst_discard;
 		new->output = dst_discard;
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index ad8556e6fd4..7946b53692d 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -221,7 +221,7 @@ static struct rt6_info ip6_blk_hole_entry_template = {
 /* allocate dst with ip6_dst_ops */
 static inline struct rt6_info *ip6_dst_alloc(struct dst_ops *ops)
 {
-	return (struct rt6_info *)dst_alloc(ops);
+	return (struct rt6_info *)dst_alloc(ops, 0);
 }
 
 static void ip6_dst_destroy(struct dst_entry *dst)
@@ -873,13 +873,12 @@ int ip6_dst_blackhole(struct sock *sk, struct dst_entry **dstp, struct flowi *fl
 {
 	struct rt6_info *ort = (struct rt6_info *) *dstp;
 	struct rt6_info *rt = (struct rt6_info *)
-		dst_alloc(&ip6_dst_blackhole_ops);
+		dst_alloc(&ip6_dst_blackhole_ops, 1);
 	struct dst_entry *new = NULL;
 
 	if (rt) {
 		new = &rt->dst;
 
-		atomic_set(&new->__refcnt, 1);
 		new->__use = 1;
 		new->input = dst_discard;
 		new->output = dst_discard;
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 8b3ef404c79..3f1257add4f 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1340,7 +1340,7 @@ static inline struct xfrm_dst *xfrm_alloc_dst(struct net *net, int family)
 	default:
 		BUG();
 	}
-	xdst = dst_alloc(dst_ops) ?: ERR_PTR(-ENOBUFS);
+	xdst = dst_alloc(dst_ops, 0) ?: ERR_PTR(-ENOBUFS);
 	xfrm_policy_put_afinfo(afinfo);
 
 	xdst->flo.ops = &xfrm_bundle_fc_ops;