inetpeer: restore small inet_peer structures

Addition of rcu_head to struct inet_peer added 16bytes on 64bit arches.

Thats a bit unfortunate, since old size was exactly 64 bytes.

This can be solved, using an union between this rcu_head an four fields,
that are normally used only when a refcount is taken on inet_peer.
rcu_head is used only when refcnt=-1, right before structure freeing.

Add a inet_peer_refcheck() function to check this assertion for a while.

We can bring back SLAB_HWCACHE_ALIGN qualifier in kmem cache creation.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 0 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index a291edbbc97f..03430de46166 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2881,6 +2881,7 @@ static int rt_fill_info(struct net *net,
         error = rt->dst.error;
         expires = rt->dst.expires ? rt->dst.expires - jiffies : 0;
         if (rt->peer) {
+                inet_peer_refcheck(rt->peer);
                 id = atomic_read(&rt->peer->ip_id_count) & 0xffff;
                 if (rt->peer->tcp_ts_stamp) {
                         ts = rt->peer->tcp_ts;