commit 1bbdceef1e535add893bf71d7b7ab102e4eb69eb
author Hannes Frederic Sowa <hannes@stressinduktion.org> Sat Oct 19 21:48:57 2013 +0200
committer David S. Miller <davem@davemloft.net> Sat Oct 19 19:45:35 2013 -0400
tree e2eed21c778d0a6458f8350ce5f6fbfc6c58810e
parent b23a002fc6f0c19846ee0382f019429af54a27e9

inet: convert inet_ehash_secret and ipv6_hash_secret to net_get_random_once

Initialize the ehash and ipv6_hash_secrets with net_get_random_once.

Each compilation unit gets its own secret now:
  ipv4/inet_hashtables.o
  ipv4/udp.o
  ipv6/inet6_hashtables.o
  ipv6/udp.o
  rds/connection.o

The functions still get inlined into the hashing functions. In the fast
path we have at most two (needed in ipv6) if (unlikely(...)).

Cc: Eric Dumazet <edumazet@google.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/rds/connection.c

diff --git a/net/rds/connection.c b/net/rds/connection.c
index 45e2366..378c3a6 100644
--- a/net/rds/connection.c
+++ b/net/rds/connection.c
@@ -51,10 +51,16 @@
 
 static struct hlist_head *rds_conn_bucket(__be32 laddr, __be32 faddr)
 {
+	static u32 rds_hash_secret __read_mostly;
+
+	unsigned long hash;
+
+	net_get_random_once(&rds_hash_secret, sizeof(rds_hash_secret));
+
 	/* Pass NULL, don't need struct net for hash */
-	unsigned long hash = __inet_ehashfn(be32_to_cpu(laddr), 0,
-					    be32_to_cpu(faddr), 0,
-					    inet_ehash_secret);
+	hash = __inet_ehashfn(be32_to_cpu(laddr), 0,
+			      be32_to_cpu(faddr), 0,
+			      rds_hash_secret);
 	return &rds_conn_hash[hash & RDS_CONNECTION_HASH_MASK];
 }