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Date: Fri, 10 Jul 2015 17:32:28 +0200
From: Frederic Konrad <fred.konrad@greensocs.com>
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Subject: Re: [Qemu-devel] [RFC PATCH 1/3] cpus: protect queued_work_* with
	work_mutex.
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To: Paolo Bonzini <pbonzini@redhat.com>, qemu-devel@nongnu.org, mttcg@greensocs.com
Cc: mark.burton@greensocs.com, alex.bennee@linaro.org, a.rigo@virtualopensystems.com, guillaume.delbergue@greensocs.com

On 10/07/2015 17:22, Paolo Bonzini wrote:
>
> On 10/07/2015 17:19, fred.konrad@greensocs.com wrote:
>> +    qemu_mutex_lock(&cpu->work_mutex);
>>       while ((wi = cpu->queued_work_first)) {
>>           cpu->queued_work_first = wi->next;
>>           wi->func(wi->data);
> Please unlock the mutex while calling the callback.
>
> Paolo
>
>> @@ -905,6 +912,8 @@ static void flush_queued_work(CPUState *cpu)
>>           }
>>       }
>>       cpu->queued_work_last = NULL;
>> +    qemu_mutex_unlock(&cpu->work_mutex);
>> +
>>       qemu_cond_broadcast(&qemu_work_cond);

I think something like that can work because we don't have two
flush_queued_work at the same time on the same CPU?

static void flush_queued_work(CPUState *cpu)
{
     struct qemu_work_item *wi;

     if (cpu->queued_work_first == NULL) {
         return;
     }

     qemu_mutex_lock(&cpu->work_mutex);
     while ((wi = cpu->queued_work_first)) {
         cpu->queued_work_first = wi->next;
         qemu_mutex_unlock(&cpu->work_mutex);
         wi->func(wi->data);
         qemu_mutex_lock(&cpu->work_mutex);
         wi->done = true;
         if (wi->free) {
             g_free(wi);
         }
     }
     cpu->queued_work_last = NULL;
     qemu_mutex_unlock(&cpu->work_mutex);

     qemu_cond_broadcast(&qemu_work_cond);
}

Fred