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Date: Wed, 5 Jan 2011 19:53:44 +0000
From: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Message-ID: <20110105195343.GA9821@stefanha-thinkpad.localdomain>
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	<20110104052708.15887.7563.stgit@localhost6.localdomain6>
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Subject: [Qemu-devel] Re: [PATCH 01/13] Add aiocb_mutex and aiocb_completion.
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To: Arun R Bharadwaj <arun@linux.vnet.ibm.com>
Cc: aliguori@us.ibm.com, qemu-devel@nongnu.org, aneesh.kumar@linux.vnet.ibm.com

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);

Stefan