[PATCH 3.16 352/410] net: Refactor rtable initialization

From: Ben Hutchings
Date: Thu Jun 07 2018 - 10:13:40 EST


3.16.57-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: David Ahern <dsa@xxxxxxxxxxxxxxxxxxx>

commit d08c4f355403840fad98d9918db51a7113f38ee8 upstream.

All callers to rt_dst_alloc have nearly the same initialization following
a successful allocation. Consolidate it into rt_dst_alloc.

Signed-off-by: David Ahern <dsa@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1435,12 +1435,33 @@ static void rt_set_nexthop(struct rtable
}

static struct rtable *rt_dst_alloc(struct net_device *dev,
+ unsigned int flags, u16 type,
bool nopolicy, bool noxfrm, bool will_cache)
{
- return dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
- (will_cache ? 0 : (DST_HOST | DST_NOCACHE)) |
- (nopolicy ? DST_NOPOLICY : 0) |
- (noxfrm ? DST_NOXFRM : 0));
+ struct rtable *rt;
+
+ rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
+ (will_cache ? 0 : (DST_HOST | DST_NOCACHE)) |
+ (nopolicy ? DST_NOPOLICY : 0) |
+ (noxfrm ? DST_NOXFRM : 0));
+
+ if (rt) {
+ rt->rt_genid = rt_genid_ipv4(dev_net(dev));
+ rt->rt_flags = flags;
+ rt->rt_type = type;
+ rt->rt_is_input = 0;
+ rt->rt_iif = 0;
+ rt->rt_pmtu = 0;
+ rt->rt_gateway = 0;
+ rt->rt_uses_gateway = 0;
+ INIT_LIST_HEAD(&rt->rt_uncached);
+
+ rt->dst.output = ip_output;
+ if (flags & RTCF_LOCAL)
+ rt->dst.input = ip_local_deliver;
+ }
+
+ return rt;
}

/* called in rcu_read_lock() section */
@@ -1480,6 +1501,7 @@ static int ip_route_input_mc(struct sk_b
{
struct in_device *in_dev = __in_dev_get_rcu(dev);
struct rtable *rth;
+ unsigned int flags = RTCF_MULTICAST;
u32 itag = 0;
int err;

@@ -1487,7 +1509,10 @@ static int ip_route_input_mc(struct sk_b
if (err)
return err;

- rth = rt_dst_alloc(dev_net(dev)->loopback_dev,
+ if (our)
+ flags |= RTCF_LOCAL;
+
+ rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
if (!rth)
return -ENOBUFS;
@@ -1496,20 +1521,7 @@ static int ip_route_input_mc(struct sk_b
rth->dst.tclassid = itag;
#endif
rth->dst.output = ip_rt_bug;
-
- rth->rt_genid = rt_genid_ipv4(dev_net(dev));
- rth->rt_flags = RTCF_MULTICAST;
- rth->rt_type = RTN_MULTICAST;
rth->rt_is_input= 1;
- rth->rt_iif = 0;
- rth->rt_pmtu = 0;
- rth->rt_gateway = 0;
- rth->rt_uses_gateway = 0;
- INIT_LIST_HEAD(&rth->rt_uncached);
- if (our) {
- rth->dst.input= ip_local_deliver;
- rth->rt_flags |= RTCF_LOCAL;
- }

#ifdef CONFIG_IP_MROUTE
if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
@@ -1650,7 +1662,7 @@ rt_cache:
}
}

- rth = rt_dst_alloc(out_dev->dev,
+ rth = rt_dst_alloc(out_dev->dev, 0, res->type,
IN_DEV_CONF_GET(in_dev, NOPOLICY),
IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
if (!rth) {
@@ -1658,19 +1670,10 @@ rt_cache:
goto cleanup;
}

- rth->rt_genid = rt_genid_ipv4(dev_net(rth->dst.dev));
- rth->rt_flags = 0;
- rth->rt_type = res->type;
rth->rt_is_input = 1;
- rth->rt_iif = 0;
- rth->rt_pmtu = 0;
- rth->rt_gateway = 0;
- rth->rt_uses_gateway = 0;
- INIT_LIST_HEAD(&rth->rt_uncached);
RT_CACHE_STAT_INC(in_slow_tot);

rth->dst.input = ip_forward;
- rth->dst.output = ip_output;

rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag);
skb_dst_set(skb, &rth->dst);
@@ -1821,26 +1824,17 @@ local_input:
}
}

- rth = rt_dst_alloc(net->loopback_dev,
+ rth = rt_dst_alloc(net->loopback_dev, flags | RTCF_LOCAL, res.type,
IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
if (!rth)
goto e_nobufs;

- rth->dst.input= ip_local_deliver;
rth->dst.output= ip_rt_bug;
#ifdef CONFIG_IP_ROUTE_CLASSID
rth->dst.tclassid = itag;
#endif
-
- rth->rt_genid = rt_genid_ipv4(net);
- rth->rt_flags = flags|RTCF_LOCAL;
- rth->rt_type = res.type;
rth->rt_is_input = 1;
- rth->rt_iif = 0;
- rth->rt_pmtu = 0;
- rth->rt_gateway = 0;
- rth->rt_uses_gateway = 0;
- INIT_LIST_HEAD(&rth->rt_uncached);
+
RT_CACHE_STAT_INC(in_slow_tot);
if (res.type == RTN_UNREACHABLE) {
rth->dst.input= ip_error;
@@ -2037,29 +2031,16 @@ rt_cache:
}

add:
- rth = rt_dst_alloc(dev_out,
+ rth = rt_dst_alloc(dev_out, flags, type,
IN_DEV_CONF_GET(in_dev, NOPOLICY),
IN_DEV_CONF_GET(in_dev, NOXFRM),
do_cache);
if (!rth)
return ERR_PTR(-ENOBUFS);

- rth->dst.output = ip_output;
-
- rth->rt_genid = rt_genid_ipv4(dev_net(dev_out));
- rth->rt_flags = flags;
- rth->rt_type = type;
- rth->rt_is_input = 0;
rth->rt_iif = orig_oif ? : 0;
- rth->rt_pmtu = 0;
- rth->rt_gateway = 0;
- rth->rt_uses_gateway = 0;
- INIT_LIST_HEAD(&rth->rt_uncached);
-
RT_CACHE_STAT_INC(out_slow_tot);

- if (flags & RTCF_LOCAL)
- rth->dst.input = ip_local_deliver;
if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
if (flags & RTCF_LOCAL &&
!(dev_out->flags & IFF_LOOPBACK)) {