* [PATCH net] ipv4: Revert removal of rt_uses_gateway
@ 2019-09-17 17:39 David Ahern
2019-09-17 18:50 ` Julian Anastasov
2019-09-21 1:30 ` Jakub Kicinski
0 siblings, 2 replies; 6+ messages in thread
From: David Ahern @ 2019-09-17 17:39 UTC (permalink / raw)
To: davem; +Cc: netdev, ja, David Ahern
From: David Ahern <dsahern@gmail.com>
Julian noted that rt_uses_gateway has a more subtle use than 'is gateway
set':
https://lore.kernel.org/netdev/alpine.LFD.2.21.1909151104060.2546@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 <ja@ssi.bg>
Signed-off-by: David Ahern <dsahern@gmail.com>
---
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
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH net] ipv4: Revert removal of rt_uses_gateway
2019-09-17 17:39 [PATCH net] ipv4: Revert removal of rt_uses_gateway David Ahern
@ 2019-09-17 18:50 ` Julian Anastasov
2019-09-17 18:55 ` David Ahern
2019-09-21 1:30 ` Jakub Kicinski
1 sibling, 1 reply; 6+ messages in thread
From: Julian Anastasov @ 2019-09-17 18:50 UTC (permalink / raw)
To: David Ahern; +Cc: davem, netdev, David Ahern
Hello,
On Tue, 17 Sep 2019, David Ahern wrote:
> From: David Ahern <dsahern@gmail.com>
>
> Julian noted that rt_uses_gateway has a more subtle use than 'is gateway
> set':
> https://lore.kernel.org/netdev/alpine.LFD.2.21.1909151104060.2546@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 <ja@ssi.bg>
> Signed-off-by: David Ahern <dsahern@gmail.com>
Looks good to me, thanks!
Reviewed-by: Julian Anastasov <ja@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 <ja@ssi.bg>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net] ipv4: Revert removal of rt_uses_gateway
2019-09-17 18:50 ` Julian Anastasov
@ 2019-09-17 18:55 ` David Ahern
2019-09-17 22:02 ` Julian Anastasov
0 siblings, 1 reply; 6+ messages in thread
From: David Ahern @ 2019-09-17 18:55 UTC (permalink / raw)
To: Julian Anastasov, David Ahern; +Cc: davem, netdev
On 9/17/19 12:50 PM, Julian Anastasov wrote:
>
> Looks good to me, thanks!
>
> Reviewed-by: Julian Anastasov <ja@ssi.bg>
>
BTW, do you have any tests for the rt_uses_gateway paths - showing why
it is needed?
All of the pmtu, redirect, fib tests, etc worked fine without the
special flag. Sure, the 'ip ro get' had extra data; it seems like that
could be handled.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net] ipv4: Revert removal of rt_uses_gateway
2019-09-17 18:55 ` David Ahern
@ 2019-09-17 22:02 ` Julian Anastasov
0 siblings, 0 replies; 6+ messages in thread
From: Julian Anastasov @ 2019-09-17 22:02 UTC (permalink / raw)
To: David Ahern; +Cc: David Ahern, davem, netdev
Hello,
On Tue, 17 Sep 2019, David Ahern wrote:
> On 9/17/19 12:50 PM, Julian Anastasov wrote:
> >
> > Looks good to me, thanks!
> >
> > Reviewed-by: Julian Anastasov <ja@ssi.bg>
> >
>
> BTW, do you have any tests for the rt_uses_gateway paths - showing why
> it is needed?
No special tests.
> All of the pmtu, redirect, fib tests, etc worked fine without the
> special flag. Sure, the 'ip ro get' had extra data; it seems like that
> could be handled.
I'll explain. In the period before the route cache
was removed in 3.6, there were two fields: rt_dst and rt_gateway.
For targets on LAN both contained the target. For targets via
gateway (nh_gw), rt_dst still stores the target but rt_gateway
stored the nh_gw. In short, rt_gateway always contained the
next hop IP for neigh resolving.
In 3.6, rt_dst was removed and only rt_gateway remained
to store nh_gw. As fnhe_rth/nh_pcpu_rth_output were used to
cache the output route, rt_gateway can not contain any IP
because the route can be used for any target on the LAN.
This is true even now, rt_gateway is 0 for cached routes
that are not DST_HOST, i.e. not for single target IP.
Why this matters? There are users such as IPVS,
TEE, raw.c (IP_HDRINCL) that use FLOWI_FLAG_KNOWN_NH to
request route with rt_gateway != 0 to be returned, i.e.
they want rt_gateway to store a next hop IP for neigh
resolving but to put different IP in iph->daddr. This is
honoured by rt_nexthop(), it prefers rt_gateway before the
iph->daddr. With this FLOWI flag the routing will avoid
returning routes with rt_gateway = 0 (cached in NH), instead
it will allocate DST_HOST route which can safely hold IP
in rt_gateway.
So, in 3.7 commit 155e8336c373 ("ipv4: introduce
rt_uses_gateway") was created to restore the knowledge
that rt_dst != rt_gateway means route via GW and also
commit c92b96553a80 ("ipv4: Add FLOWI_FLAG_KNOWN_NH")
to make sure packets are routed by requested next hop and
not by iph->daddr.
You see the places that need to know if rt_gateway
contains nh_gw (via GW) or just a requested next hop (when
nh_gw is 0). It matters for cases where strict source routes
should be on connected network.
In simple tests things are working without rt_uses_gateway
flag because it is a corner case to see above cases combined
with strict source routing or MTU locking. Not sure if we can
use some trick to support it differently without such flag.
Regards
--
Julian Anastasov <ja@ssi.bg>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net] ipv4: Revert removal of rt_uses_gateway
2019-09-17 17:39 [PATCH net] ipv4: Revert removal of rt_uses_gateway David Ahern
2019-09-17 18:50 ` Julian Anastasov
@ 2019-09-21 1:30 ` Jakub Kicinski
2019-09-21 1:32 ` David Ahern
1 sibling, 1 reply; 6+ messages in thread
From: Jakub Kicinski @ 2019-09-21 1:30 UTC (permalink / raw)
To: David Ahern; +Cc: davem, netdev, ja, David Ahern
On Tue, 17 Sep 2019 10:39:49 -0700, David Ahern wrote:
> From: David Ahern <dsahern@gmail.com>
>
> Julian noted that rt_uses_gateway has a more subtle use than 'is gateway
> set':
> https://lore.kernel.org/netdev/alpine.LFD.2.21.1909151104060.2546@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 <ja@ssi.bg>
> Signed-off-by: David Ahern <dsahern@gmail.com>
I'm assuming the mix of u8 and __u8 is intentional, since this is a partial revert :)
Applied, queued, thanks!
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net] ipv4: Revert removal of rt_uses_gateway
2019-09-21 1:30 ` Jakub Kicinski
@ 2019-09-21 1:32 ` David Ahern
0 siblings, 0 replies; 6+ messages in thread
From: David Ahern @ 2019-09-21 1:32 UTC (permalink / raw)
To: Jakub Kicinski, David Ahern; +Cc: davem, netdev, ja
On 9/20/19 7:30 PM, Jakub Kicinski wrote:
> I'm assuming the mix of u8 and __u8 is intentional, since this is a partial revert :)
original patch for rt_uses_gateway used __u8 so yes put that back.
not sure why I used u8 for the new field, but left it on the move.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2019-09-21 1:32 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-09-17 17:39 [PATCH net] ipv4: Revert removal of rt_uses_gateway David Ahern
2019-09-17 18:50 ` Julian Anastasov
2019-09-17 18:55 ` David Ahern
2019-09-17 22:02 ` Julian Anastasov
2019-09-21 1:30 ` Jakub Kicinski
2019-09-21 1:32 ` David Ahern
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.