Re: [Qemu-devel] [PATCH 4/7] blockjob: centralize QMP event emissions

[Jeff Cody <jcody@redhat.com>]

On Thu, Oct 13, 2016 at 06:56:59PM -0400, John Snow wrote:
> There's no reason to leave this to blockdev; we can do it in blockjobs
> directly and get rid of an extra callback for most users.
> 
> All non-internal events, even those created outside of QMP, will
> consistently emit events.
> 
> Signed-off-by: John Snow <jsnow@redhat.com>
> ---
>  block/commit.c            |  8 ++++----
>  block/mirror.c            |  6 ++----
>  block/stream.c            |  7 +++----
>  block/trace-events        |  5 ++---
>  blockdev.c                | 42 ++++++++----------------------------------
>  blockjob.c                | 23 +++++++++++++++++++----
>  include/block/block_int.h | 17 ++++-------------
>  include/block/blockjob.h  | 17 -----------------
>  8 files changed, 42 insertions(+), 83 deletions(-)
> 
> diff --git a/block/commit.c b/block/commit.c
> index f29e341..475a375 100644
> --- a/block/commit.c
> +++ b/block/commit.c
> @@ -209,8 +209,8 @@ static const BlockJobDriver commit_job_driver = {
>  
>  void commit_start(const char *job_id, BlockDriverState *bs,
>                    BlockDriverState *base, BlockDriverState *top, int64_t speed,
> -                  BlockdevOnError on_error, BlockCompletionFunc *cb,
> -                  void *opaque, const char *backing_file_str, Error **errp)
> +                  BlockdevOnError on_error, const char *backing_file_str,
> +                  Error **errp)
>  {
>      CommitBlockJob *s;
>      BlockReopenQueue *reopen_queue = NULL;
> @@ -233,7 +233,7 @@ void commit_start(const char *job_id, BlockDriverState *bs,
>      }
>  
>      s = block_job_create(job_id, &commit_job_driver, bs, speed,
> -                         BLOCK_JOB_DEFAULT, cb, opaque, errp);
> +                         BLOCK_JOB_DEFAULT, NULL, NULL, errp);
>      if (!s) {
>          return;
>      }
> @@ -276,7 +276,7 @@ void commit_start(const char *job_id, BlockDriverState *bs,
>      s->on_error = on_error;
>      s->common.co = qemu_coroutine_create(commit_run, s);
>  
> -    trace_commit_start(bs, base, top, s, s->common.co, opaque);
> +    trace_commit_start(bs, base, top, s, s->common.co);
>      qemu_coroutine_enter(s->common.co);
>  }
>  
> diff --git a/block/mirror.c b/block/mirror.c
> index 15d2d10..4374fb4 100644
> --- a/block/mirror.c
> +++ b/block/mirror.c
> @@ -979,9 +979,7 @@ void mirror_start(const char *job_id, BlockDriverState *bs,
>                    MirrorSyncMode mode, BlockMirrorBackingMode backing_mode,
>                    BlockdevOnError on_source_error,
>                    BlockdevOnError on_target_error,
> -                  bool unmap,
> -                  BlockCompletionFunc *cb,
> -                  void *opaque, Error **errp)
> +                  bool unmap, Error **errp)
>  {
>      bool is_none_mode;
>      BlockDriverState *base;
> @@ -994,7 +992,7 @@ void mirror_start(const char *job_id, BlockDriverState *bs,
>      base = mode == MIRROR_SYNC_MODE_TOP ? backing_bs(bs) : NULL;
>      mirror_start_job(job_id, bs, BLOCK_JOB_DEFAULT, target, replaces,
>                       speed, granularity, buf_size, backing_mode,
> -                     on_source_error, on_target_error, unmap, cb, opaque, errp,
> +                     on_source_error, on_target_error, unmap, NULL, NULL, errp,
>                       &mirror_job_driver, is_none_mode, base, false);
>  }
>  
> diff --git a/block/stream.c b/block/stream.c
> index eeb6f52..7d6877d 100644
> --- a/block/stream.c
> +++ b/block/stream.c
> @@ -216,13 +216,12 @@ static const BlockJobDriver stream_job_driver = {
>  
>  void stream_start(const char *job_id, BlockDriverState *bs,
>                    BlockDriverState *base, const char *backing_file_str,
> -                  int64_t speed, BlockdevOnError on_error,
> -                  BlockCompletionFunc *cb, void *opaque, Error **errp)
> +                  int64_t speed, BlockdevOnError on_error, Error **errp)
>  {
>      StreamBlockJob *s;
>  
>      s = block_job_create(job_id, &stream_job_driver, bs, speed,
> -                         BLOCK_JOB_DEFAULT, cb, opaque, errp);
> +                         BLOCK_JOB_DEFAULT, NULL, NULL, errp);
>      if (!s) {
>          return;
>      }
> @@ -232,6 +231,6 @@ void stream_start(const char *job_id, BlockDriverState *bs,
>  
>      s->on_error = on_error;
>      s->common.co = qemu_coroutine_create(stream_run, s);
> -    trace_stream_start(bs, base, s, s->common.co, opaque);
> +    trace_stream_start(bs, base, s, s->common.co);
>      qemu_coroutine_enter(s->common.co);
>  }
> diff --git a/block/trace-events b/block/trace-events
> index 05fa13c..c12f91b 100644
> --- a/block/trace-events
> +++ b/block/trace-events
> @@ -20,11 +20,11 @@ bdrv_co_do_copy_on_readv(void *bs, int64_t offset, unsigned int bytes, int64_t c
>  
>  # block/stream.c
>  stream_one_iteration(void *s, int64_t sector_num, int nb_sectors, int is_allocated) "s %p sector_num %"PRId64" nb_sectors %d is_allocated %d"
> -stream_start(void *bs, void *base, void *s, void *co, void *opaque) "bs %p base %p s %p co %p opaque %p"
> +stream_start(void *bs, void *base, void *s, void *co) "bs %p base %p s %p co %p"
>  
>  # block/commit.c
>  commit_one_iteration(void *s, int64_t sector_num, int nb_sectors, int is_allocated) "s %p sector_num %"PRId64" nb_sectors %d is_allocated %d"
> -commit_start(void *bs, void *base, void *top, void *s, void *co, void *opaque) "bs %p base %p top %p s %p co %p opaque %p"
> +commit_start(void *bs, void *base, void *top, void *s, void *co) "bs %p base %p top %p s %p co %p"
>  
>  # block/mirror.c
>  mirror_start(void *bs, void *s, void *co, void *opaque) "bs %p s %p co %p opaque %p"
> @@ -52,7 +52,6 @@ qmp_block_job_cancel(void *job) "job %p"
>  qmp_block_job_pause(void *job) "job %p"
>  qmp_block_job_resume(void *job) "job %p"
>  qmp_block_job_complete(void *job) "job %p"
> -block_job_cb(void *bs, void *job, int ret) "bs %p job %p ret %d"
>  qmp_block_stream(void *bs, void *job) "bs %p job %p"
>  
>  # block/raw-win32.c
> diff --git a/blockdev.c b/blockdev.c
> index 0ce305c..22a1280 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -2905,31 +2905,6 @@ out:
>      aio_context_release(aio_context);
>  }
>  
> -static void block_job_cb(void *opaque, int ret)
> -{
> -    /* Note that this function may be executed from another AioContext besides
> -     * the QEMU main loop.  If you need to access anything that assumes the
> -     * QEMU global mutex, use a BH or introduce a mutex.
> -     */
> -
> -    BlockDriverState *bs = opaque;
> -    const char *msg = NULL;
> -
> -    trace_block_job_cb(bs, bs->job, ret);
> -
> -    assert(bs->job);
> -
> -    if (ret < 0) {
> -        msg = strerror(-ret);
> -    }
> -
> -    if (block_job_is_cancelled(bs->job)) {
> -        block_job_event_cancelled(bs->job);
> -    } else {
> -        block_job_event_completed(bs->job, msg);
> -    }
> -}
> -
>  void qmp_block_stream(bool has_job_id, const char *job_id, const char *device,
>                        bool has_base, const char *base,
>                        bool has_backing_file, const char *backing_file,
> @@ -2981,7 +2956,7 @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device,
>      base_name = has_backing_file ? backing_file : base_name;
>  
>      stream_start(has_job_id ? job_id : NULL, bs, base_bs, base_name,
> -                 has_speed ? speed : 0, on_error, block_job_cb, bs, &local_err);
> +                 has_speed ? speed : 0, on_error, &local_err);
>      if (local_err) {
>          error_propagate(errp, local_err);
>          goto out;
> @@ -3084,12 +3059,12 @@ void qmp_block_commit(bool has_job_id, const char *job_id, const char *device,
>              goto out;
>          }
>          commit_active_start(has_job_id ? job_id : NULL, bs, base_bs,
> -                            BLOCK_JOB_DEFAULT, speed, on_error, block_job_cb,
> -                            bs, &local_err, false);
> +                            BLOCK_JOB_DEFAULT, speed, on_error, NULL, NULL,
> +                            &local_err, false);
>      } else {
>          commit_start(has_job_id ? job_id : NULL, bs, base_bs, top_bs, speed,
> -                     on_error, block_job_cb, bs,
> -                     has_backing_file ? backing_file : NULL, &local_err);
> +                     on_error, has_backing_file ? backing_file : NULL,
> +                     &local_err);
>      }
>      if (local_err != NULL) {
>          error_propagate(errp, local_err);
> @@ -3210,7 +3185,7 @@ static void do_drive_backup(DriveBackup *backup, BlockJobTxn *txn, Error **errp)
>      backup_start(backup->job_id, bs, target_bs, backup->speed, backup->sync,
>                   bmap, backup->compress, backup->on_source_error,
>                   backup->on_target_error, BLOCK_JOB_DEFAULT,
> -                 block_job_cb, bs, txn, &local_err);
> +                 NULL, NULL, txn, &local_err);
>      bdrv_unref(target_bs);
>      if (local_err != NULL) {
>          error_propagate(errp, local_err);
> @@ -3281,7 +3256,7 @@ void do_blockdev_backup(BlockdevBackup *backup, BlockJobTxn *txn, Error **errp)
>      backup_start(backup->job_id, bs, target_bs, backup->speed, backup->sync,
>                   NULL, backup->compress, backup->on_source_error,
>                   backup->on_target_error, BLOCK_JOB_DEFAULT,
> -                 block_job_cb, bs, txn, &local_err);
> +                 NULL, NULL, txn, &local_err);
>      if (local_err != NULL) {
>          error_propagate(errp, local_err);
>      }
> @@ -3360,8 +3335,7 @@ static void blockdev_mirror_common(const char *job_id, BlockDriverState *bs,
>      mirror_start(job_id, bs, target,
>                   has_replaces ? replaces : NULL,
>                   speed, granularity, buf_size, sync, backing_mode,
> -                 on_source_error, on_target_error, unmap,
> -                 block_job_cb, bs, errp);
> +                 on_source_error, on_target_error, unmap, errp);
>  }
>  
>  void qmp_drive_mirror(DriveMirror *arg, Error **errp)
> diff --git a/blockjob.c b/blockjob.c
> index 017905a..e32cb78 100644
> --- a/blockjob.c
> +++ b/blockjob.c
> @@ -38,6 +38,9 @@
>  #include "qemu/timer.h"
>  #include "qapi-event.h"
>  
> +static void block_job_event_cancelled(BlockJob *job);
> +static void block_job_event_completed(BlockJob *job, const char *msg);
> +
>  /* Transactional group of block jobs */
>  struct BlockJobTxn {
>  
> @@ -124,7 +127,6 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
>      BlockBackend *blk;
>      BlockJob *job;
>  
> -    assert(cb);
>      if (bs->job) {
>          error_setg(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
>          return NULL;
> @@ -230,7 +232,20 @@ static void block_job_completed_single(BlockJob *job)
>              job->driver->abort(job);
>          }
>      }
> -    job->cb(job->opaque, job->ret);
> +
> +    if (job->cb) {
> +        job->cb(job->opaque, job->ret);
> +    }
> +    if (block_job_is_cancelled(job)) {
> +        block_job_event_cancelled(job);
> +    } else {
> +        const char *msg = NULL;
> +        if (job->ret < 0) {
> +            msg = strerror(-job->ret);
> +        }
> +        block_job_event_completed(job, msg);
> +    }
> +
>      if (job->txn) {
>          block_job_txn_unref(job->txn);
>      }
> @@ -535,7 +550,7 @@ static void block_job_iostatus_set_err(BlockJob *job, int error)
>      }
>  }
>  
> -void block_job_event_cancelled(BlockJob *job)
> +static void block_job_event_cancelled(BlockJob *job)
>  {
>      if (block_job_is_internal(job)) {
>          return;
> @@ -549,7 +564,7 @@ void block_job_event_cancelled(BlockJob *job)
>                                          &error_abort);
>  }
>  
> -void block_job_event_completed(BlockJob *job, const char *msg)
> +static void block_job_event_completed(BlockJob *job, const char *msg)
>  {
>      if (block_job_is_internal(job)) {
>          return;
> diff --git a/include/block/block_int.h b/include/block/block_int.h
> index 98f1c7f..dfbc53d 100644
> --- a/include/block/block_int.h
> +++ b/include/block/block_int.h
> @@ -647,8 +647,6 @@ int is_windows_drive(const char *filename);
>   * the new backing file if the job completes. Ignored if @base is %NULL.
>   * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
>   * @on_error: The action to take upon error.
> - * @cb: Completion function for the job.
> - * @opaque: Opaque pointer value passed to @cb.
>   * @errp: Error object.
>   *
>   * Start a streaming operation on @bs.  Clusters that are unallocated
> @@ -660,8 +658,7 @@ int is_windows_drive(const char *filename);
>   */
>  void stream_start(const char *job_id, BlockDriverState *bs,
>                    BlockDriverState *base, const char *backing_file_str,
> -                  int64_t speed, BlockdevOnError on_error,
> -                  BlockCompletionFunc *cb, void *opaque, Error **errp);
> +                  int64_t speed, BlockdevOnError on_error, Error **errp);
>  
>  /**
>   * commit_start:
> @@ -672,16 +669,14 @@ void stream_start(const char *job_id, BlockDriverState *bs,
>   * @base: Block device that will be written into, and become the new top.
>   * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
>   * @on_error: The action to take upon error.
> - * @cb: Completion function for the job.
> - * @opaque: Opaque pointer value passed to @cb.
>   * @backing_file_str: String to use as the backing file in @top's overlay
>   * @errp: Error object.
>   *
>   */
>  void commit_start(const char *job_id, BlockDriverState *bs,
>                    BlockDriverState *base, BlockDriverState *top, int64_t speed,
> -                  BlockdevOnError on_error, BlockCompletionFunc *cb,
> -                  void *opaque, const char *backing_file_str, Error **errp);
> +                  BlockdevOnError on_error, const char *backing_file_str,
> +                  Error **errp);
>  /**
>   * commit_active_start:
>   * @job_id: The id of the newly-created job, or %NULL to use the
> @@ -719,8 +714,6 @@ void commit_active_start(const char *job_id, BlockDriverState *bs,
>   * @on_source_error: The action to take upon error reading from the source.
>   * @on_target_error: The action to take upon error writing to the target.
>   * @unmap: Whether to unmap target where source sectors only contain zeroes.
> - * @cb: Completion function for the job.
> - * @opaque: Opaque pointer value passed to @cb.
>   * @errp: Error object.
>   *
>   * Start a mirroring operation on @bs.  Clusters that are allocated
> @@ -734,9 +727,7 @@ void mirror_start(const char *job_id, BlockDriverState *bs,
>                    MirrorSyncMode mode, BlockMirrorBackingMode backing_mode,
>                    BlockdevOnError on_source_error,
>                    BlockdevOnError on_target_error,
> -                  bool unmap,
> -                  BlockCompletionFunc *cb,
> -                  void *opaque, Error **errp);
> +                  bool unmap, Error **errp);
>  
>  /*
>   * backup_start:
> diff --git a/include/block/blockjob.h b/include/block/blockjob.h
> index fdb31e0..928f0b8 100644
> --- a/include/block/blockjob.h
> +++ b/include/block/blockjob.h
> @@ -374,23 +374,6 @@ void block_job_resume(BlockJob *job);
>  void block_job_enter(BlockJob *job);
>  
>  /**
> - * block_job_event_cancelled:
> - * @job: The job whose information is requested.
> - *
> - * Send a BLOCK_JOB_CANCELLED event for the specified job.
> - */
> -void block_job_event_cancelled(BlockJob *job);
> -
> -/**
> - * block_job_ready:
> - * @job: The job which is now ready to complete.
> - * @msg: Error message. Only present on failure.
> - *
> - * Send a BLOCK_JOB_COMPLETED event for the specified job.
> - */
> -void block_job_event_completed(BlockJob *job, const char *msg);
> -
> -/**
>   * block_job_ready:
>   * @job: The job which is now ready to complete.
>   *
> -- 
> 2.7.4
> 

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