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net: build_ehash_secret() and rt_bind_peer() cleanups
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Now cmpxchg() is available on all arches, we can use it in
build_ehash_secret() and rt_bind_peer() instead of using spinlocks.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Eric Dumazet authored and David S. Miller committed Aug 20, 2010
1 parent 4da7950 commit 49e8ab0
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Showing 2 changed files with 4 additions and 13 deletions.
8 changes: 3 additions & 5 deletions net/ipv4/af_inet.c
Original file line number Diff line number Diff line change
Expand Up @@ -227,18 +227,16 @@ EXPORT_SYMBOL(inet_ehash_secret);

/*
* inet_ehash_secret must be set exactly once
* Instead of using a dedicated spinlock, we (ab)use inetsw_lock
*/
void build_ehash_secret(void)
{
u32 rnd;

do {
get_random_bytes(&rnd, sizeof(rnd));
} while (rnd == 0);
spin_lock_bh(&inetsw_lock);
if (!inet_ehash_secret)
inet_ehash_secret = rnd;
spin_unlock_bh(&inetsw_lock);

cmpxchg(&inet_ehash_secret, 0, rnd);
}
EXPORT_SYMBOL(build_ehash_secret);

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9 changes: 1 addition & 8 deletions net/ipv4/route.c
Original file line number Diff line number Diff line change
Expand Up @@ -1268,18 +1268,11 @@ static int rt_intern_hash(unsigned hash, struct rtable *rt,

void rt_bind_peer(struct rtable *rt, int create)
{
static DEFINE_SPINLOCK(rt_peer_lock);
struct inet_peer *peer;

peer = inet_getpeer(rt->rt_dst, create);

spin_lock_bh(&rt_peer_lock);
if (rt->peer == NULL) {
rt->peer = peer;
peer = NULL;
}
spin_unlock_bh(&rt_peer_lock);
if (peer)
if (peer && cmpxchg(&rt->peer, NULL, peer) != NULL)
inet_putpeer(peer);
}

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