From: Eric Dumazet <eric.dumazet@gmail.com>
To: stefani@seibold.net
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
davem@davemloft.net, netdev@vger.kernel.org
Subject: Re: [PATCH] UDPCP Communication Protocol
Date: Fri, 31 Dec 2010 12:25:58 +0100 [thread overview]
Message-ID: <1293794758.2973.49.camel@edumazet-laptop> (raw)
In-Reply-To: <1293787785-3834-1-git-send-email-stefani@seibold.net>
Le vendredi 31 décembre 2010 à 10:29 +0100, stefani@seibold.net a
écrit :
> + if (!list_empty(&usk->destlist)) {
> + state->sk = (struct sock *)usk;
> + state->dest = list_first_entry(&usk->destlist,
> + struct udpcp_dest, list);
> + sock_hold(state->sk);
> +
> + if (atomic_read(&state->sk->sk_refcnt) != 1) {
> + spin_unlock_irqrestore(&spinlock, flags);
> + return state;
> + }
> + atomic_dec(&state->sk->sk_refcnt);
> + }
> +
I am trying to understand what you are doing here.
It seems racy to me.
Apparently, what you want is to take a reference only if actual
sk_refcnt is not zero.
I suggest using atomic_inc_notzero(&state->sk->sk_refcnt) to avoid the
race in atomic_dec().
next prev parent reply other threads:[~2010-12-31 11:25 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-31 9:29 [PATCH] UDPCP Communication Protocol stefani
2010-12-31 10:00 ` Eric Dumazet
2010-12-31 10:22 ` Stefani Seibold
2010-12-31 10:41 ` Eric Dumazet
2010-12-31 11:23 ` Stefani Seibold
2010-12-31 11:54 ` Eric Dumazet
2011-01-01 21:40 ` Stefani Seibold
2011-01-10 22:28 ` Hagen Paul Pfeifer
2010-12-31 10:15 ` Eric Dumazet
2010-12-31 10:29 ` Stefani Seibold
2010-12-31 10:35 ` Eric Dumazet
2010-12-31 11:25 ` Eric Dumazet [this message]
2010-12-31 12:00 ` Eric Dumazet
2011-01-01 21:28 ` Stefani Seibold
2010-12-31 17:46 ` Stephen Hemminger
2010-12-31 17:46 ` Stephen Hemminger
2011-01-06 20:11 ` Pavel Machek
2011-01-06 20:17 ` David Miller
2011-01-10 22:53 ` Jesper Juhl
2011-01-11 0:49 ` Hagen Paul Pfeifer
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