linux-kernel - Re: [patch] remove redundant kioctx->users ref count

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Date:	Fri, 13 Oct 2006 10:33:59 -0400
From:	Benjamin LaHaise <bcrl@...ck.org>
To:	"Chen, Kenneth W" <kenneth.w.chen@...el.com>
Cc:	'Zach Brown' <zach.brown@...cle.com>,
	'Suparna Bhattacharya' <suparna@...ibm.com>,
	"Lahaise, Benjamin C" <benjamin.c.lahaise@...el.com>,
	linux-kernel@...r.kernel.org, 'linux-aio' <linux-aio@...ck.org>
Subject: Re: [patch] remove redundant kioctx->users ref count

On Thu, Oct 12, 2006 at 04:54:46PM -0700, Chen, Kenneth W wrote:
> @@ -1015,9 +1010,6 @@ put_rq:
>  	if (waitqueue_active(&ctx->wait))
>  		wake_up(&ctx->wait);
>  
> -	if (ret)
> -		put_ioctx(ctx);
> -
>  	return ret;
>  }

This part makes me worry -- at this point we no longer have anything 
pinning the ioctx, yet we touch ->wait after dropping the lock.  The 
only way around this is if rcu is introduced in the final free of an 
ioctx to ensure the structure remains around for a sufficient grace 
period.

		-ben
-- 
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