Hello,On Tue, 17 Sep 2019, David Ahern wrote: > From: David Ahern <dsah...@gmail.com> > > Julian noted that rt_uses_gateway has a more subtle use than 'is gateway > set': > > https://lore.kernel.org/netdev/alpine.lfd.2.21.1909151104060.2...@ja.home.ssi.bg/ > > Revert that part of the commit referenced in the Fixes tag. > > Currently, there are no u8 holes in 'struct rtable'. There is a 4-byte hole > in the second cacheline which contains the gateway declaration. So move > rt_gw_family down to the gateway declarations since they are always used > together, and then re-use that u8 for rt_uses_gateway. End result is that > rtable size is unchanged. > > Fixes: 1550c171935d ("ipv4: Prepare rtable for IPv6 gateway") > Reported-by: Julian Anastasov <j...@ssi.bg> > Signed-off-by: David Ahern <dsah...@gmail.com> Looks good to me, thanks! Reviewed-by: Julian Anastasov <j...@ssi.bg> > --- > drivers/infiniband/core/addr.c | 2 +- > include/net/route.h | 3 ++- > net/ipv4/inet_connection_sock.c | 4 ++-- > net/ipv4/ip_forward.c | 2 +- > net/ipv4/ip_output.c | 2 +- > net/ipv4/route.c | 36 +++++++++++++++++++++--------------- > net/ipv4/xfrm4_policy.c | 1 + > 7 files changed, 29 insertions(+), 21 deletions(-) > > diff --git a/drivers/infiniband/core/addr.c b/drivers/infiniband/core/addr.c > index 9b76a8fcdd24..bf539c34ccd3 100644 > --- a/drivers/infiniband/core/addr.c > +++ b/drivers/infiniband/core/addr.c > @@ -352,7 +352,7 @@ static bool has_gateway(const struct dst_entry *dst, > sa_family_t family) > > if (family == AF_INET) { > rt = container_of(dst, struct rtable, dst); > - return rt->rt_gw_family == AF_INET; > + return rt->rt_uses_gateway; > } > > rt6 = container_of(dst, struct rt6_info, dst); > diff --git a/include/net/route.h b/include/net/route.h > index dfce19c9fa96..6c516840380d 100644 > --- a/include/net/route.h > +++ b/include/net/route.h > @@ -53,10 +53,11 @@ struct rtable { > unsigned int rt_flags; > __u16 rt_type; > __u8 rt_is_input; > - u8 rt_gw_family; > + __u8 rt_uses_gateway; > > int rt_iif; > > + u8 rt_gw_family; > /* Info on neighbour */ > union { > __be32 rt_gw4; > diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c > index f5c163d4771b..a9183543ca30 100644 > --- a/net/ipv4/inet_connection_sock.c > +++ b/net/ipv4/inet_connection_sock.c > @@ -560,7 +560,7 @@ struct dst_entry *inet_csk_route_req(const struct sock > *sk, > rt = ip_route_output_flow(net, fl4, sk); > if (IS_ERR(rt)) > goto no_route; > - if (opt && opt->opt.is_strictroute && rt->rt_gw_family) > + if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway) > goto route_err; > rcu_read_unlock(); > return &rt->dst; > @@ -598,7 +598,7 @@ struct dst_entry *inet_csk_route_child_sock(const struct > sock *sk, > rt = ip_route_output_flow(net, fl4, sk); > if (IS_ERR(rt)) > goto no_route; > - if (opt && opt->opt.is_strictroute && rt->rt_gw_family) > + if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway) > goto route_err; > return &rt->dst; > > diff --git a/net/ipv4/ip_forward.c b/net/ipv4/ip_forward.c > index 06f6f280b9ff..00ec819f949b 100644 > --- a/net/ipv4/ip_forward.c > +++ b/net/ipv4/ip_forward.c > @@ -123,7 +123,7 @@ int ip_forward(struct sk_buff *skb) > > rt = skb_rtable(skb); > > - if (opt->is_strictroute && rt->rt_gw_family) > + if (opt->is_strictroute && rt->rt_uses_gateway) > goto sr_failed; > > IPCB(skb)->flags |= IPSKB_FORWARDED; > diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c > index cc7ef0d05bbd..da521790cd63 100644 > --- a/net/ipv4/ip_output.c > +++ b/net/ipv4/ip_output.c > @@ -499,7 +499,7 @@ int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, > struct flowi *fl, > skb_dst_set_noref(skb, &rt->dst); > > packet_routed: > - if (inet_opt && inet_opt->opt.is_strictroute && rt->rt_gw_family) > + if (inet_opt && inet_opt->opt.is_strictroute && rt->rt_uses_gateway) > goto no_route; > > /* OK, we know where to send it, allocate and build IP header. */ > diff --git a/net/ipv4/route.c b/net/ipv4/route.c > index b6a6f18c3dd1..7dcce724c78b 100644 > --- a/net/ipv4/route.c > +++ b/net/ipv4/route.c > @@ -635,6 +635,7 @@ static void fill_route_from_fnhe(struct rtable *rt, > struct fib_nh_exception *fnh > > if (fnhe->fnhe_gw) { > rt->rt_flags |= RTCF_REDIRECTED; > + rt->rt_uses_gateway = 1; > rt->rt_gw_family = AF_INET; > rt->rt_gw4 = fnhe->fnhe_gw; > } > @@ -1313,7 +1314,7 @@ static unsigned int ipv4_mtu(const struct dst_entry > *dst) > mtu = READ_ONCE(dst->dev->mtu); > > if (unlikely(ip_mtu_locked(dst))) { > - if (rt->rt_gw_family && mtu > 576) > + if (rt->rt_uses_gateway && mtu > 576) > mtu = 576; > } > > @@ -1569,6 +1570,7 @@ static void rt_set_nexthop(struct rtable *rt, __be32 > daddr, > struct fib_nh_common *nhc = FIB_RES_NHC(*res); > > if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) { > + rt->rt_uses_gateway = 1; > rt->rt_gw_family = nhc->nhc_gw_family; > /* only INET and INET6 are supported */ > if (likely(nhc->nhc_gw_family == AF_INET)) > @@ -1634,6 +1636,7 @@ struct rtable *rt_dst_alloc(struct net_device *dev, > rt->rt_iif = 0; > rt->rt_pmtu = 0; > rt->rt_mtu_locked = 0; > + rt->rt_uses_gateway = 0; > rt->rt_gw_family = 0; > rt->rt_gw4 = 0; > INIT_LIST_HEAD(&rt->rt_uncached); > @@ -2694,6 +2697,7 @@ struct dst_entry *ipv4_blackhole_route(struct net *net, > struct dst_entry *dst_or > rt->rt_genid = rt_genid_ipv4(net); > rt->rt_flags = ort->rt_flags; > rt->rt_type = ort->rt_type; > + rt->rt_uses_gateway = ort->rt_uses_gateway; > rt->rt_gw_family = ort->rt_gw_family; > if (rt->rt_gw_family == AF_INET) > rt->rt_gw4 = ort->rt_gw4; > @@ -2778,21 +2782,23 @@ static int rt_fill_info(struct net *net, __be32 dst, > __be32 src, > if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr)) > goto nla_put_failure; > } > - if (rt->rt_gw_family == AF_INET && > - nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) { > - goto nla_put_failure; > - } else if (rt->rt_gw_family == AF_INET6) { > - int alen = sizeof(struct in6_addr); > - struct nlattr *nla; > - struct rtvia *via; > - > - nla = nla_reserve(skb, RTA_VIA, alen + 2); > - if (!nla) > + if (rt->rt_uses_gateway) { > + if (rt->rt_gw_family == AF_INET && > + nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) { > goto nla_put_failure; > - > - via = nla_data(nla); > - via->rtvia_family = AF_INET6; > - memcpy(via->rtvia_addr, &rt->rt_gw6, alen); > + } else if (rt->rt_gw_family == AF_INET6) { > + int alen = sizeof(struct in6_addr); > + struct nlattr *nla; > + struct rtvia *via; > + > + nla = nla_reserve(skb, RTA_VIA, alen + 2); > + if (!nla) > + goto nla_put_failure; > + > + via = nla_data(nla); > + via->rtvia_family = AF_INET6; > + memcpy(via->rtvia_addr, &rt->rt_gw6, alen); > + } > } > > expires = rt->dst.expires; > diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c > index cdef8f9a3b01..35b84b52b702 100644 > --- a/net/ipv4/xfrm4_policy.c > +++ b/net/ipv4/xfrm4_policy.c > @@ -85,6 +85,7 @@ static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct > net_device *dev, > xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST | > RTCF_LOCAL); > xdst->u.rt.rt_type = rt->rt_type; > + xdst->u.rt.rt_uses_gateway = rt->rt_uses_gateway; > xdst->u.rt.rt_gw_family = rt->rt_gw_family; > if (rt->rt_gw_family == AF_INET) > xdst->u.rt.rt_gw4 = rt->rt_gw4; > -- > 2.11.0 Regards -- Julian Anastasov <j...@ssi.bg>
