ipv4: Make output route lookup return rtable directly.

Instead of on the stack.

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

1 files changed, 49 insertions, 51 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 63d37004ee66..5090e956f6b8 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1014,8 +1014,8 @@ static int slow_chain_length(const struct rtable *head)
         return length >> FRACT_BITS;
 }
 
-static int rt_intern_hash(unsigned hash, struct rtable *rt,
-                          struct rtable **rp, struct sk_buff *skb, int ifindex)
+static struct rtable *rt_intern_hash(unsigned hash, struct rtable *rt,
+                                     struct sk_buff *skb, int ifindex)
 {
         struct rtable   *rth, *cand;
         struct rtable __rcu **rthp, **candp;
@@ -1056,7 +1056,7 @@ restart:
                                         printk(KERN_WARNING
                                             "Neighbour table failure & not caching routes.\n");
                                 ip_rt_put(rt);
-                                return err;
+                                return ERR_PTR(err);
                         }
                 }
 
@@ -1093,11 +1093,9 @@ restart:
                         spin_unlock_bh(rt_hash_lock_addr(hash));
 
                         rt_drop(rt);
-                        if (rp)
-                                *rp = rth;
-                        else
+                        if (skb)
                                 skb_dst_set(skb, &rth->dst);
-                        return 0;
+                        return rth;
                 }
 
                 if (!atomic_read(&rth->dst.__refcnt)) {
@@ -1154,7 +1152,7 @@ restart:
 
                         if (err != -ENOBUFS) {
                                 rt_drop(rt);
-                                return err;
+                                return ERR_PTR(err);
                         }
 
                         /* Neighbour tables are full and nothing
@@ -1175,7 +1173,7 @@ restart:
                         if (net_ratelimit())
                                 printk(KERN_WARNING "ipv4: Neighbour table overflow.\n");
                         rt_drop(rt);
-                        return -ENOBUFS;
+                        return ERR_PTR(-ENOBUFS);
                 }
         }
 
@@ -1201,11 +1199,9 @@ restart:
         spin_unlock_bh(rt_hash_lock_addr(hash));
 
 skip_hashing:
-        if (rp)
-                *rp = rt;
-        else
+        if (skb)
                 skb_dst_set(skb, &rt->dst);
-        return 0;
+        return rt;
 }
 
 static atomic_t __rt_peer_genid = ATOMIC_INIT(0);
@@ -1896,7 +1892,10 @@ static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
         RT_CACHE_STAT_INC(in_slow_mc);
 
         hash = rt_hash(daddr, saddr, dev->ifindex, rt_genid(dev_net(dev)));
-        return rt_intern_hash(hash, rth, NULL, skb, dev->ifindex);
+        rth = rt_intern_hash(hash, rth, skb, dev->ifindex);
+        err = 0;
+        if (IS_ERR(rth))
+                err = PTR_ERR(rth);
 
 e_nobufs:
         return -ENOBUFS;
@@ -2051,7 +2050,10 @@ static int ip_mkroute_input(struct sk_buff *skb,
         /* put it into the cache */
         hash = rt_hash(daddr, saddr, fl->iif,
                        rt_genid(dev_net(rth->dst.dev)));
-        return rt_intern_hash(hash, rth, NULL, skb, fl->iif);
+        rth = rt_intern_hash(hash, rth, skb, fl->iif);
+        if (IS_ERR(rth))
+                return PTR_ERR(rth);
+        return 0;
 }
 
 /*
@@ -2194,7 +2196,10 @@ local_input:
         }
         rth->rt_type    = res.type;
         hash = rt_hash(daddr, saddr, fl.iif, rt_genid(net));
-        err = rt_intern_hash(hash, rth, NULL, skb, fl.iif);
+        rth = rt_intern_hash(hash, rth, skb, fl.iif);
+        err = 0;
+        if (IS_ERR(rth))
+                err = PTR_ERR(rth);
         goto out;
 
 no_route:
@@ -2422,8 +2427,8 @@ static struct rtable *__mkroute_output(const struct fib_result *res,
  * called with rcu_read_lock();
  */
 
-static int ip_route_output_slow(struct net *net, struct rtable **rp,
-                                const struct flowi *oldflp)
+static struct rtable *ip_route_output_slow(struct net *net,
+                                           const struct flowi *oldflp)
 {
         u32 tos = RT_FL_TOS(oldflp);
         struct flowi fl = { .fl4_dst = oldflp->fl4_dst,
@@ -2438,8 +2443,6 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp,
         unsigned int flags = 0;
         struct net_device *dev_out = NULL;
         struct rtable *rth;
-        int err;
-
 
         res.fi          = NULL;
 #ifdef CONFIG_IP_MULTIPLE_TABLES
@@ -2448,7 +2451,7 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp,
 
         rcu_read_lock();
         if (oldflp->fl4_src) {
-                err = -EINVAL;
+                rth = ERR_PTR(-EINVAL);
                 if (ipv4_is_multicast(oldflp->fl4_src) ||
                     ipv4_is_lbcast(oldflp->fl4_src) ||
                     ipv4_is_zeronet(oldflp->fl4_src))
@@ -2499,13 +2502,13 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp,
 
         if (oldflp->oif) {
                 dev_out = dev_get_by_index_rcu(net, oldflp->oif);
-                err = -ENODEV;
+                rth = ERR_PTR(-ENODEV);
                 if (dev_out == NULL)
                         goto out;
 
                 /* RACE: Check return value of inet_select_addr instead. */
                 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
-                        err = -ENETUNREACH;
+                        rth = ERR_PTR(-ENETUNREACH);
                         goto out;
                 }
                 if (ipv4_is_local_multicast(oldflp->fl4_dst) ||
@@ -2563,7 +2566,7 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp,
                         res.type = RTN_UNICAST;
                         goto make_route;
                 }
-                err = -ENETUNREACH;
+                rth = ERR_PTR(-ENETUNREACH);
                 goto out;
         }
 
@@ -2598,23 +2601,20 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp,
 
 make_route:
         rth = __mkroute_output(&res, &fl, oldflp, dev_out, flags);
-        if (IS_ERR(rth))
-                err = PTR_ERR(rth);
-        else {
+        if (!IS_ERR(rth)) {
                 unsigned int hash;
 
                 hash = rt_hash(oldflp->fl4_dst, oldflp->fl4_src, oldflp->oif,
                                rt_genid(dev_net(dev_out)));
-                err = rt_intern_hash(hash, rth, rp, NULL, oldflp->oif);
+                rth = rt_intern_hash(hash, rth, NULL, oldflp->oif);
         }
 
 out:
         rcu_read_unlock();
-        return err;
+        return rth;
 }
 
-int __ip_route_output_key(struct net *net, struct rtable **rp,
-                          const struct flowi *flp)
+struct rtable *__ip_route_output_key(struct net *net, const struct flowi *flp)
 {
         struct rtable *rth;
         unsigned int hash;
@@ -2639,15 +2639,14 @@ int __ip_route_output_key(struct net *net, struct rtable **rp,
                         dst_use(&rth->dst, jiffies);
                         RT_CACHE_STAT_INC(out_hit);
                         rcu_read_unlock_bh();
-                        *rp = rth;
-                        return 0;
+                        return rth;
                 }
                 RT_CACHE_STAT_INC(out_hlist_search);
         }
         rcu_read_unlock_bh();
 
 slow_output:
-        return ip_route_output_slow(net, rp, flp);
+        return ip_route_output_slow(net, flp);
 }
 EXPORT_SYMBOL_GPL(__ip_route_output_key);
 
@@ -2717,34 +2716,29 @@ struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_or
         return rt ? &rt->dst : ERR_PTR(-ENOMEM);
 }
 
-int ip_route_output_flow(struct net *net, struct rtable **rp, struct flowi *flp,
-                         struct sock *sk)
+struct rtable *ip_route_output_flow(struct net *net, struct flowi *flp,
+                                    struct sock *sk)
 {
-        int err;
+        struct rtable *rt = __ip_route_output_key(net, flp);
 
-        if ((err = __ip_route_output_key(net, rp, flp)) != 0)
-                return err;
+        if (IS_ERR(rt))
+                return rt;
 
         if (flp->proto) {
                 if (!flp->fl4_src)
-                        flp->fl4_src = (*rp)->rt_src;
+                        flp->fl4_src = rt->rt_src;
                 if (!flp->fl4_dst)
-                        flp->fl4_dst = (*rp)->rt_dst;
-                *rp = (struct rtable *) xfrm_lookup(net, &(*rp)->dst, flp, sk, 0);
-                if (IS_ERR(*rp)) {
-                        err = PTR_ERR(*rp);
-                        *rp = NULL;
-                        return err;
-                }
+                        flp->fl4_dst = rt->rt_dst;
+                rt = (struct rtable *) xfrm_lookup(net, &rt->dst, flp, sk, 0);
         }
 
-        return 0;
+        return rt;
 }
 EXPORT_SYMBOL_GPL(ip_route_output_flow);
 
-int ip_route_output_key(struct net *net, struct rtable **rp, struct flowi *flp)
+struct rtable *ip_route_output_key(struct net *net, struct flowi *flp)
 {
-        return ip_route_output_flow(net, rp, flp, NULL);
+        return ip_route_output_flow(net, flp, NULL);
 }
 EXPORT_SYMBOL(ip_route_output_key);
 
@@ -2915,7 +2909,11 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh, void
                         .oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0,
                         .mark = mark,
                 };
-                err = ip_route_output_key(net, &rt, &fl);
+                rt = ip_route_output_key(net, &fl);
+
+                err = 0;
+                if (IS_ERR(rt))
+                        err = PTR_ERR(rt);
         }
 
         if (err)