netdev - [PATCH net-next 3/3] inet: remove old fragmentation hash initializing

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Date:	Wed, 23 Oct 2013 11:06:57 +0200
From:	Hannes Frederic Sowa <hannes@...essinduktion.org>
To:	netdev@...r.kernel.org
Cc:	netfilter-devel@...r.kernel.org,
	Hannes Frederic Sowa <hannes@...essinduktion.org>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH net-next 3/3] inet: remove old fragmentation hash initializing

All fragmentation hash secrets now get initialized by their
corresponding hash function with net_get_random_once. Thus we can
eliminate the initial seeding.

Also provide a comment that hash secret seeding happens at the first
call to the corresponding hashing function.

Cc: David S. Miller <davem@...emloft.net>
Cc: Eric Dumazet <edumazet@...gle.com>
Signed-off-by: Hannes Frederic Sowa <hannes@...essinduktion.org>
---
 include/net/inet_frag.h  | 4 ++++
 net/ipv4/inet_fragment.c | 3 ---
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h
index bfcbc00..6f59de9 100644
--- a/include/net/inet_frag.h
+++ b/include/net/inet_frag.h
@@ -64,6 +64,10 @@ struct inet_frags {
 	rwlock_t		lock ____cacheline_aligned_in_smp;
 	int			secret_interval;
 	struct timer_list	secret_timer;
+
+	/* The first call to hashfn is responsible to initialize
+	 * rnd. This is best done with net_get_random_once.
+	 */
 	u32			rnd;
 	int			qsize;
 
diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c
index c5313a9..bb075fc 100644
--- a/net/ipv4/inet_fragment.c
+++ b/net/ipv4/inet_fragment.c
@@ -93,9 +93,6 @@ void inet_frags_init(struct inet_frags *f)
 	}
 	rwlock_init(&f->lock);
 
-	f->rnd = (u32) ((totalram_pages ^ (totalram_pages >> 7)) ^
-				   (jiffies ^ (jiffies >> 6)));
-
 	setup_timer(&f->secret_timer, inet_frag_secret_rebuild,
 			(unsigned long)f);
 	f->secret_timer.expires = jiffies + f->secret_interval;
-- 
1.8.3.1

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