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Date: Tue, 18 Sep 2012 16:33:10 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [RFC PATCH 14/16] qcow2: Execute
 run_dependent_requests() without lock
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To: Kevin Wolf <kwolf@redhat.com>
Cc: qemu-devel@nongnu.org

Il 18/09/2012 13:40, Kevin Wolf ha scritto:
>  static void run_dependent_requests(BDRVQcowState *s, QCowL2Meta *m)
>  {
> -    /* Take the request off the list of running requests */
> -    if (m->nb_clusters != 0) {
> -        QLIST_REMOVE(m, next_in_flight);
> -    }
> -
>      /* Restart all dependent requests */
>      if (!qemu_co_queue_empty(&m->dependent_requests)) {
> -        qemu_co_mutex_unlock(&s->lock);
>          qemu_co_queue_restart_all(&m->dependent_requests);
> -        qemu_co_mutex_lock(&s->lock);
>      }

The comment and if can go away.

Perhaps this patch could be moved earlier in the series?  (Just asking,
in case the rebase is not too painful).

Paolo

>  }
>  
> @@ -800,10 +793,18 @@ again:
>          goto again;
>      }
>  
> +    qemu_co_mutex_unlock(&s->lock);
> +
> +    /* Take the request off the list of running requests */
> +    if (m->nb_clusters != 0) {
> +        QLIST_REMOVE(m, next_in_flight);
> +    }
> +
> +    /* Meanwhile some new dependencies could have accumulated */