ipv4: Consolidate ipv4 dst allocation logic.

This also allows us to combine all the dst->flags settings and avoid
read/modify/write sequences to this struct member.

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

1 files changed, 21 insertions, 31 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index b2b3c9e0a61..79a28718102 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1816,6 +1816,21 @@ static void rt_set_nexthop(struct rtable *rt, struct fib_result *res, u32 itag)
         rt->rt_type = res->type;
 }
 
+static struct rtable *rt_dst_alloc(bool nopolicy, bool noxfrm)
+{
+        struct rtable *rt = dst_alloc(&ipv4_dst_ops);
+        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);
+        }
+        return rt;
+}
+
 /* called in rcu_read_lock() section */
 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
                                 u8 tos, struct net_device *dev, int our)
@@ -1846,17 +1861,12 @@ static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
                 if (err < 0)
                         goto e_err;
         }
-        rth = dst_alloc(&ipv4_dst_ops);
+        rth = rt_dst_alloc(IN_DEV_CONF_GET(in_dev, NOPOLICY), false);
         if (!rth)
                 goto e_nobufs;
 
         rth->dst.output = ip_rt_bug;
-        rth->dst.obsolete = -1;
 
-        atomic_set(&rth->dst.__refcnt, 1);
-        rth->dst.flags= DST_HOST;
-        if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
-                rth->dst.flags |= DST_NOPOLICY;
         rth->fl.fl4_dst = daddr;
         rth->rt_dst     = daddr;
         rth->fl.fl4_tos = tos;
@@ -1985,19 +1995,13 @@ static int __mkroute_input(struct sk_buff *skb,
                 }
         }
 
-
-        rth = dst_alloc(&ipv4_dst_ops);
+        rth = rt_dst_alloc(IN_DEV_CONF_GET(in_dev, NOPOLICY),
+                           IN_DEV_CONF_GET(out_dev, NOXFRM));
         if (!rth) {
                 err = -ENOBUFS;
                 goto cleanup;
         }
 
-        atomic_set(&rth->dst.__refcnt, 1);
-        rth->dst.flags= DST_HOST;
-        if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
-                rth->dst.flags |= DST_NOPOLICY;
-        if (IN_DEV_CONF_GET(out_dev, NOXFRM))
-                rth->dst.flags |= DST_NOXFRM;
         rth->fl.fl4_dst = daddr;
         rth->rt_dst     = daddr;
         rth->fl.fl4_tos = tos;
@@ -2012,7 +2016,6 @@ static int __mkroute_input(struct sk_buff *skb,
         rth->fl.oif     = 0;
         rth->rt_spec_dst= spec_dst;
 
-        rth->dst.obsolete = -1;
         rth->dst.input = ip_forward;
         rth->dst.output = ip_output;
         rth->rt_genid = rt_genid(dev_net(rth->dst.dev));
@@ -2162,18 +2165,13 @@ brd_input:
         RT_CACHE_STAT_INC(in_brd);
 
 local_input:
-        rth = dst_alloc(&ipv4_dst_ops);
+        rth = rt_dst_alloc(IN_DEV_CONF_GET(in_dev, NOPOLICY), false);
         if (!rth)
                 goto e_nobufs;
 
         rth->dst.output= ip_rt_bug;
-        rth->dst.obsolete = -1;
         rth->rt_genid = rt_genid(net);
 
-        atomic_set(&rth->dst.__refcnt, 1);
-        rth->dst.flags= DST_HOST;
-        if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
-                rth->dst.flags |= DST_NOPOLICY;
         rth->fl.fl4_dst = daddr;
         rth->rt_dst     = daddr;
         rth->fl.fl4_tos = tos;
@@ -2366,18 +2364,11 @@ static struct rtable *__mkroute_output(struct fib_result *res,
                         res->fi = NULL;
         }
 
-
-        rth = dst_alloc(&ipv4_dst_ops);
+        rth = rt_dst_alloc(IN_DEV_CONF_GET(in_dev, NOPOLICY),
+                           IN_DEV_CONF_GET(in_dev, NOXFRM));
         if (!rth)
                 return ERR_PTR(-ENOBUFS);
 
-        atomic_set(&rth->dst.__refcnt, 1);
-        rth->dst.flags= DST_HOST;
-        if (IN_DEV_CONF_GET(in_dev, NOXFRM))
-                rth->dst.flags |= DST_NOXFRM;
-        if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
-                rth->dst.flags |= DST_NOPOLICY;
-
         rth->fl.fl4_dst = oldflp->fl4_dst;
         rth->fl.fl4_tos = tos;
         rth->fl.fl4_src = oldflp->fl4_src;
@@ -2394,7 +2385,6 @@ static struct rtable *__mkroute_output(struct fib_result *res,
         rth->rt_spec_dst= fl->fl4_src;
 
         rth->dst.output=ip_output;
-        rth->dst.obsolete = -1;
         rth->rt_genid = rt_genid(dev_net(dev_out));
 
         RT_CACHE_STAT_INC(out_slow_tot);