Date: Wed, 12 Sep 2007 14:42:22 -0400
To: Neil Brown <neilb@suse.de>
Cc: Wolfgang Walter <wolfgang.walter@studentenwerk.mhn.de>,
       trond.myklebust@fys.uio.no, netdev@vger.kernel.org,
       nfs@lists.sourceforge.net, linux-kernel@vger.kernel.org
Subject: Re: [patch] sunrpc: make closing of old temporary sockets work
	(was: problems with lockd in 2.6.22.6)
Message-ID: <20070912184222.GG4274@fieldses.org>
References: <200709121407.11151.wolfgang.walter@studentenwerk.mhn.de> <18151.62510.891210.485277@notabene.brown>
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From: "J. Bruce Fields" <bfields@fieldses.org>
Sender: linux-kernel-owner@vger.kernel.org
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On Wed, Sep 12, 2007 at 04:14:06PM +0200, Neil Brown wrote:
> So it is in 2.6.21 and later and should probably go to .stable for .21
> and .22.
> 
> Bruce:  for you :-)

OK, thanks!  But, (as is alas often the case) I'm still confused:

>  		if (!test_and_set_bit(SK_OLD, &svsk->sk_flags))
>  			continue;
> -		if (atomic_read(&svsk->sk_inuse) || test_bit(SK_BUSY, &svsk->sk_flags))
> +		if (atomic_read(&svsk->sk_inuse) > 1
> +		    || test_bit(SK_BUSY, &svsk->sk_flags))
>  			continue;
>  		atomic_inc(&svsk->sk_inuse);
>  		list_move(le, &to_be_aged);

What is it that ensures svsk->sk_inuse isn't incremented or SK_BUSY set
after that test?  Not all the code that does either of those is under
the same serv->sv_lock lock that this code is.

--b.
-
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