Re: [Qemu-devel] [PATCH 5/7] Blockjobs: Internalize user_pause logic

[Jeff Cody <jcody@redhat.com>]

On Thu, Oct 13, 2016 at 06:57:00PM -0400, John Snow wrote:
> BlockJobs will begin hiding their state in preparation for some
> refactorings anyway, so let's internalize the user_pause mechanism
> instead of leaving it to callers to correctly manage.
> 
> Signed-off-by: John Snow <jsnow@redhat.com>
> ---
>  blockdev.c               | 12 +++++-------
>  blockjob.c               | 22 ++++++++++++++++++++--
>  include/block/blockjob.h | 26 ++++++++++++++++++++++++++
>  3 files changed, 51 insertions(+), 9 deletions(-)
> 
> diff --git a/blockdev.c b/blockdev.c
> index 22a1280..1661d08 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -3579,7 +3579,7 @@ void qmp_block_job_cancel(const char *device,
>          force = false;
>      }
>  
> -    if (job->user_paused && !force) {
> +    if (block_job_user_paused(job) && !force) {
>          error_setg(errp, "The block job for device '%s' is currently paused",
>                     device);
>          goto out;
> @@ -3596,13 +3596,12 @@ void qmp_block_job_pause(const char *device, Error **errp)
>      AioContext *aio_context;
>      BlockJob *job = find_block_job(device, &aio_context, errp);
>  
> -    if (!job || job->user_paused) {
> +    if (!job || block_job_user_paused(job)) {
>          return;
>      }
>  
> -    job->user_paused = true;
>      trace_qmp_block_job_pause(job);
> -    block_job_pause(job);
> +    block_job_user_pause(job);
>      aio_context_release(aio_context);
>  }
>  
> @@ -3611,14 +3610,13 @@ void qmp_block_job_resume(const char *device, Error **errp)
>      AioContext *aio_context;
>      BlockJob *job = find_block_job(device, &aio_context, errp);
>  
> -    if (!job || !job->user_paused) {
> +    if (!job || !block_job_user_paused(job)) {
>          return;
>      }
>  
> -    job->user_paused = false;
>      trace_qmp_block_job_resume(job);
>      block_job_iostatus_reset(job);
> -    block_job_resume(job);
> +    block_job_user_resume(job);
>      aio_context_release(aio_context);
>  }
>  
> diff --git a/blockjob.c b/blockjob.c
> index e32cb78..d118a1f 100644
> --- a/blockjob.c
> +++ b/blockjob.c
> @@ -362,11 +362,22 @@ void block_job_pause(BlockJob *job)
>      job->pause_count++;
>  }
>  
> +void block_job_user_pause(BlockJob *job)
> +{
> +    job->user_paused = true;
> +    block_job_pause(job);
> +}
> +
>  static bool block_job_should_pause(BlockJob *job)
>  {
>      return job->pause_count > 0;
>  }
>  
> +bool block_job_user_paused(BlockJob *job)
> +{
> +    return job ? job->user_paused : 0;
> +}
> +
>  void coroutine_fn block_job_pause_point(BlockJob *job)
>  {
>      if (!block_job_should_pause(job)) {
> @@ -403,6 +414,14 @@ void block_job_resume(BlockJob *job)
>      block_job_enter(job);
>  }
>  
> +void block_job_user_resume(BlockJob *job)
> +{
> +    if (job && job->user_paused && job->pause_count > 0) {
> +        job->user_paused = false;
> +        block_job_resume(job);
> +    }
> +}
> +
>  void block_job_enter(BlockJob *job)
>  {
>      if (job->co && !job->busy) {
> @@ -626,8 +645,7 @@ BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
>      }
>      if (action == BLOCK_ERROR_ACTION_STOP) {
>          /* make the pause user visible, which will be resumed from QMP. */
> -        job->user_paused = true;
> -        block_job_pause(job);
> +        block_job_user_pause(job);
>          block_job_iostatus_set_err(job, error);
>      }
>      return action;
> diff --git a/include/block/blockjob.h b/include/block/blockjob.h
> index 928f0b8..5b61140 100644
> --- a/include/block/blockjob.h
> +++ b/include/block/blockjob.h
> @@ -358,6 +358,23 @@ void coroutine_fn block_job_pause_point(BlockJob *job);
>  void block_job_pause(BlockJob *job);
>  
>  /**
> + * block_job_user_pause:
> + * @job: The job to be paused.
> + *
> + * Asynchronously pause the specified job.
> + * Do not allow a resume until a matching call to block_job_user_resume.
> + */
> +void block_job_user_pause(BlockJob *job);
> +
> +/**
> + * block_job_paused:
> + * @job: The job to query.
> + *
> + * Returns true if the job is user-paused.
> + */
> +bool block_job_user_paused(BlockJob *job);
> +
> +/**
>   * block_job_resume:
>   * @job: The job to be resumed.
>   *
> @@ -366,6 +383,15 @@ void block_job_pause(BlockJob *job);
>  void block_job_resume(BlockJob *job);
>  
>  /**
> + * block_job_user_resume:
> + * @job: The job to be resumed.
> + *
> + * Resume the specified job.
> + * Must be paired with a preceding block_job_user_pause.
> + */
> +void block_job_user_resume(BlockJob *job);
> +
> +/**
>   * block_job_enter:
>   * @job: The job to enter.
>   *
> -- 
> 2.7.4
> 

Reviewed-by: Jeff Cody <jcody@redhat.com>