From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [PATCH 1/4] [RFC] net: Explicitly initialize u64_stats_sync
 structures for lockdep
Date: Thu, 26 Sep 2013 12:26:25 -0700
Message-ID: <1380223585.3165.205.camel@edumazet-glaptop>
References: <1380220464-28840-1-git-send-email-john.stultz@linaro.org>
	 <1380220464-28840-2-git-send-email-john.stultz@linaro.org>
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Cc: LKML <linux-kernel@vger.kernel.org>,
	Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
	Mirko Lindner <mlindner@marvell.com>,
	Stephen Hemminger <stephen@networkplumber.org>,
	Roger Luethi <rl@hellgate.ch>,
	Patrick McHardy <kaber@trash.net>,
	Rusty Russell <rusty@rustcorp.com.au>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
	James Morris <jmorris@namei.org>,
	Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
	Wensong Zhang <wensong@linux-vs.org>,
	Simon Horman <horms@verge.net.au>,
	Julian Anastasov <ja@ssi.bg>, Jesse Gross <jesse@nicira.com>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"David S. Miller" <davem@davemloft.net>, netdev@vger.kernel.org,
	netfilter-devel@vger.kernel.org
To: John Stultz <john.stultz@linaro.org>
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On Thu, 2013-09-26 at 11:34 -0700, John Stultz wrote:
> In order to enable lockdep on seqcount/seqlock structures, we
> must explicitly initialize any locks.
> 

> diff --git a/include/linux/u64_stats_sync.h b/include/linux/u64_stats_sync.h
> index 8da8c4e..c450e11 100644
> --- a/include/linux/u64_stats_sync.h
> +++ b/include/linux/u64_stats_sync.h
> @@ -67,6 +67,13 @@ struct u64_stats_sync {
>  #endif
>  };
>  
> +
> +#if BITS_PER_LONG == 32 && defined(CONFIG_SMP)
> +#define u64_stats_init(syncp)	seqcount_init(syncp.seq)
> +#else
> +#define u64_stats_init(syncp)
> +#endif
> +

I would prefer a function.

static inline void u64_stats_init(struct u64_stats_sync *syncp)
{
#if BITS_PER_LONG == 32 && defined(CONFIG_SMP)
	seqcount_init(&syncp->seq);
#endif
}