From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from [140.186.70.92] (port=51919 helo=eggs.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1Pan3s-0005mU-Nc
	for qemu-devel@nongnu.org; Thu, 06 Jan 2011 05:27:17 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <arun@linux.vnet.ibm.com>) id 1Pan3r-0000jN-1R
	for qemu-devel@nongnu.org; Thu, 06 Jan 2011 05:27:16 -0500
Received: from e23smtp09.au.ibm.com ([202.81.31.142]:40564)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <arun@linux.vnet.ibm.com>) id 1Pan3q-0000jE-GF
	for qemu-devel@nongnu.org; Thu, 06 Jan 2011 05:27:14 -0500
Received: from d23relay03.au.ibm.com (d23relay03.au.ibm.com [202.81.31.245])
	by e23smtp09.au.ibm.com (8.14.4/8.13.1) with ESMTP id p06ARCL8011788
	for <qemu-devel@nongnu.org>; Thu, 6 Jan 2011 21:27:12 +1100
Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138])
	by d23relay03.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id
	p06ARCqF1409252
	for <qemu-devel@nongnu.org>; Thu, 6 Jan 2011 21:27:12 +1100
Received: from d23av02.au.ibm.com (loopback [127.0.0.1])
	by d23av02.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id
	p06ARC83009204
	for <qemu-devel@nongnu.org>; Thu, 6 Jan 2011 21:27:12 +1100
Date: Thu, 6 Jan 2011 15:57:08 +0530
From: Arun R Bharadwaj <arun@linux.vnet.ibm.com>
Message-ID: <20110106102708.GB17489@linux.vnet.ibm.com>
References: <20110104052627.15887.43436.stgit@localhost6.localdomain6>
	<20110104052708.15887.7563.stgit@localhost6.localdomain6>
	<20110105195343.GA9821@stefanha-thinkpad.localdomain>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
In-Reply-To: <20110105195343.GA9821@stefanha-thinkpad.localdomain>
Subject: [Qemu-devel] Re: [PATCH 01/13] Add aiocb_mutex and aiocb_completion.
Reply-To: arun@linux.vnet.ibm.com
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Cc: aliguori@us.ibm.com, qemu-devel@nongnu.org, aneesh.kumar@linux.vnet.ibm.com

* Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> [2011-01-05 19:53:44]:

> On Tue, Jan 04, 2011 at 10:57:08AM +0530, Arun R Bharadwaj wrote:
> > @@ -545,13 +555,19 @@ static void paio_cancel(BlockDriverAIOCB *blockacb)
> >      }
> >      mutex_unlock(&lock);
> >  
> > -    if (active) {
> > -        /* fail safe: if the aio could not be canceled, we wait for
> > -           it */
> > -        while (qemu_paio_error(acb) == EINPROGRESS)
> > -            ;
> > +    qemu_mutex_lock(&aiocb_mutex);
> > +    if (!active) {
> > +        acb->ret = -ECANCELED;
> > +    } else {
> > +        while (acb->ret == -EINPROGRESS) {
> > +            /*
> > +             * fail safe: if the aio could not be canceled,
> > +             * we wait for it
> > +             */
> > +            qemu_cond_wait(&aiocb_completion, &aiocb_mutex);
> > +        }
> >      }
> > -
> > +    qemu_mutex_unlock(&aiocb_mutex);
> >      paio_remove(acb);
> >  }
> 
> acb->ret and acb->active have been moved under aiocb_mutex.  They are still
> accessed under lock here and this needs to be fixed:
> 
> mutex_lock(&lock);
> if (!acb->active) {
>     QTAILQ_REMOVE(&request_list, acb, node);
>     acb->ret = -ECANCELED;
> } else if (acb->ret == -EINPROGRESS) {
>     active = 1;
> }
> mutex_unlock(&lock);
> 

You are right. This needs to go under aiocb_mutex too.

-arun

> Stefan