Re: [Qemu-devel] [RFC PATCH 01/12] block: Use bdrv_drain to replace uncessary bdrv_drain_all

[Paolo Bonzini <pbonzini@redhat.com>]

On 29/05/2015 12:53, Fam Zheng wrote:
> There callers work on a single BlockDriverState subtree, where using
> bdrv_drain() is more accurate.
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  block.c           | 6 +++---
>  block/snapshot.c  | 2 +-
>  migration/block.c | 2 +-
>  3 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/block.c b/block.c
> index f42d70e..e9f31b7 100644
> --- a/block.c
> +++ b/block.c
> @@ -1719,9 +1719,9 @@ void bdrv_close(BlockDriverState *bs)
>      if (bs->job) {
>          block_job_cancel_sync(bs->job);
>      }
> -    bdrv_drain_all(); /* complete I/O */
> +    bdrv_drain(bs); /* complete I/O */
>      bdrv_flush(bs);
> -    bdrv_drain_all(); /* in case flush left pending I/O */
> +    bdrv_drain(bs); /* in case flush left pending I/O */
>      notifier_list_notify(&bs->close_notifiers, bs);
>  
>      if (bs->drv) {
> @@ -3726,7 +3726,7 @@ void bdrv_attach_aio_context(BlockDriverState *bs,
>  
>  void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context)
>  {
> -    bdrv_drain_all(); /* ensure there are no in-flight requests */
> +    bdrv_drain(bs); /* ensure there are no in-flight requests */
>  
>      bdrv_detach_aio_context(bs);
>  
> diff --git a/block/snapshot.c b/block/snapshot.c
> index 50ae610..d56ec14 100644
> --- a/block/snapshot.c
> +++ b/block/snapshot.c
> @@ -238,7 +238,7 @@ int bdrv_snapshot_delete(BlockDriverState *bs,
>      }
>  
>      /* drain all pending i/o before deleting snapshot */
> -    bdrv_drain_all();
> +    bdrv_drain(bs);
>  
>      if (drv->bdrv_snapshot_delete) {
>          return drv->bdrv_snapshot_delete(bs, snapshot_id, name, errp);
> diff --git a/migration/block.c b/migration/block.c
> index ddb59cc..ed865ed 100644
> --- a/migration/block.c
> +++ b/migration/block.c
> @@ -457,7 +457,7 @@ static int mig_save_device_dirty(QEMUFile *f, BlkMigDevState *bmds,
>          blk_mig_lock();
>          if (bmds_aio_inflight(bmds, sector)) {
>              blk_mig_unlock();
> -            bdrv_drain_all();
> +            bdrv_drain(bmds->bs);
>          } else {
>              blk_mig_unlock();
>          }
> 

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>