openvswitch: Compact sw_flow_key.

Minimize padding in sw_flow_key and move 'tp' top the main struct.
These changes simplify code when accessing the transport port numbers
and the tcp flags, and makes the sw_flow_key 8 bytes smaller on 64-bit
systems (128->120 bytes).  These changes also make the keys for IPv4
packets to fit in one cache line.

There is a valid concern for safety of packing the struct
ovs_key_ipv4_tunnel, as it would be possible to take the address of
the tun_id member as a __be64 * which could result in unaligned access
in some systems. However:

- sw_flow_key itself is 64-bit aligned, so the tun_id within is
  always
  64-bit aligned.
- We never make arrays of ovs_key_ipv4_tunnel (which would force
  every
  second tun_key to be misaligned).
- We never take the address of the tun_id in to a __be64 *.
- Whereever we use struct ovs_key_ipv4_tunnel outside the
  sw_flow_key,
  it is in stack (on tunnel input functions), where compiler has full
  control of the alignment.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>

1 files changed, 19 insertions, 25 deletions

diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c
index e0fc12bbeeb1..6d8d2da0a8ec 100644
--- a/net/openvswitch/flow.c
+++ b/net/openvswitch/flow.c
@@ -64,17 +64,11 @@ u64 ovs_flow_used_time(unsigned long flow_jiffies)
 void ovs_flow_stats_update(struct sw_flow *flow, struct sk_buff *skb)
 {
         struct flow_stats *stats;
-        __be16 tcp_flags = 0;
+        __be16 tcp_flags = flow->key.tp.flags;
         int node = numa_node_id();
 
         stats = rcu_dereference(flow->stats[node]);
 
-        if (likely(flow->key.ip.proto == IPPROTO_TCP)) {
-                if (likely(flow->key.eth.type == htons(ETH_P_IP)))
-                        tcp_flags = flow->key.ipv4.tp.flags;
-                else if (likely(flow->key.eth.type == htons(ETH_P_IPV6)))
-                        tcp_flags = flow->key.ipv6.tp.flags;
-        }
         /* Check if already have node-specific stats. */
         if (likely(stats)) {
                 spin_lock(&stats->lock);
@@ -357,8 +351,8 @@ static int parse_icmpv6(struct sk_buff *skb, struct sw_flow_key *key,
         /* The ICMPv6 type and code fields use the 16-bit transport port
          * fields, so we need to store them in 16-bit network byte order.
          */
-        key->ipv6.tp.src = htons(icmp->icmp6_type);
-        key->ipv6.tp.dst = htons(icmp->icmp6_code);
+        key->tp.src = htons(icmp->icmp6_type);
+        key->tp.dst = htons(icmp->icmp6_code);
 
         if (icmp->icmp6_code == 0 &&
             (icmp->icmp6_type == NDISC_NEIGHBOUR_SOLICITATION ||
@@ -520,21 +514,21 @@ int ovs_flow_extract(struct sk_buff *skb, u16 in_port, struct sw_flow_key *key)
                 if (key->ip.proto == IPPROTO_TCP) {
                         if (tcphdr_ok(skb)) {
                                 struct tcphdr *tcp = tcp_hdr(skb);
-                                key->ipv4.tp.src = tcp->source;
-                                key->ipv4.tp.dst = tcp->dest;
-                                key->ipv4.tp.flags = TCP_FLAGS_BE16(tcp);
+                                key->tp.src = tcp->source;
+                                key->tp.dst = tcp->dest;
+                                key->tp.flags = TCP_FLAGS_BE16(tcp);
                         }
                 } else if (key->ip.proto == IPPROTO_UDP) {
                         if (udphdr_ok(skb)) {
                                 struct udphdr *udp = udp_hdr(skb);
-                                key->ipv4.tp.src = udp->source;
-                                key->ipv4.tp.dst = udp->dest;
+                                key->tp.src = udp->source;
+                                key->tp.dst = udp->dest;
                         }
                 } else if (key->ip.proto == IPPROTO_SCTP) {
                         if (sctphdr_ok(skb)) {
                                 struct sctphdr *sctp = sctp_hdr(skb);
-                                key->ipv4.tp.src = sctp->source;
-                                key->ipv4.tp.dst = sctp->dest;
+                                key->tp.src = sctp->source;
+                                key->tp.dst = sctp->dest;
                         }
                 } else if (key->ip.proto == IPPROTO_ICMP) {
                         if (icmphdr_ok(skb)) {
@@ -542,8 +536,8 @@ int ovs_flow_extract(struct sk_buff *skb, u16 in_port, struct sw_flow_key *key)
                                 /* The ICMP type and code fields use the 16-bit
                                  * transport port fields, so we need to store
                                  * them in 16-bit network byte order. */
-                                key->ipv4.tp.src = htons(icmp->type);
-                                key->ipv4.tp.dst = htons(icmp->code);
+                                key->tp.src = htons(icmp->type);
+                                key->tp.dst = htons(icmp->code);
                         }
                 }
 
@@ -589,21 +583,21 @@ int ovs_flow_extract(struct sk_buff *skb, u16 in_port, struct sw_flow_key *key)
                 if (key->ip.proto == NEXTHDR_TCP) {
                         if (tcphdr_ok(skb)) {
                                 struct tcphdr *tcp = tcp_hdr(skb);
-                                key->ipv6.tp.src = tcp->source;
-                                key->ipv6.tp.dst = tcp->dest;
-                                key->ipv6.tp.flags = TCP_FLAGS_BE16(tcp);
+                                key->tp.src = tcp->source;
+                                key->tp.dst = tcp->dest;
+                                key->tp.flags = TCP_FLAGS_BE16(tcp);
                         }
                 } else if (key->ip.proto == NEXTHDR_UDP) {
                         if (udphdr_ok(skb)) {
                                 struct udphdr *udp = udp_hdr(skb);
-                                key->ipv6.tp.src = udp->source;
-                                key->ipv6.tp.dst = udp->dest;
+                                key->tp.src = udp->source;
+                                key->tp.dst = udp->dest;
                         }
                 } else if (key->ip.proto == NEXTHDR_SCTP) {
                         if (sctphdr_ok(skb)) {
                                 struct sctphdr *sctp = sctp_hdr(skb);
-                                key->ipv6.tp.src = sctp->source;
-                                key->ipv6.tp.dst = sctp->dest;
+                                key->tp.src = sctp->source;
+                                key->tp.dst = sctp->dest;
                         }
                 } else if (key->ip.proto == NEXTHDR_ICMP) {
                         if (icmp6hdr_ok(skb)) {