Re: [Qemu-devel] [PATCH 2/8] block: add driver operation callbacks

[Liu Yuan <namei.unix@gmail.com>]

On Mon, Sep 01, 2014 at 10:28:54AM +0200, Benoît Canet wrote:
> The Monday 01 Sep 2014 à 15:43:08 (+0800), Liu Yuan wrote :
> > Driver operations are defined as callbacks passed from block upper drivers to
> > lower drivers and are supposed to be called by lower drivers.
> > 
> > Requests handling(queuing, submitting, etc.) are done in protocol tier in the
> > block layer and connection states are also maintained down there. Driver
> > operations are supposed to notify the upper tier (such as quorum) of the states
> > changes.
> > 
> > For now only two operation are added:
> > 
> > driver_disconnect: called when connection is off
> > driver_reconnect: called when connection is on after disconnection
> > 
> > Which are used to notify upper tier of the connection state.
> > 
> > Cc: Eric Blake <eblake@redhat.com>
> > Cc: Benoit Canet <benoit@irqsave.net>
> > Cc: Kevin Wolf <kwolf@redhat.com>
> > Cc: Stefan Hajnoczi <stefanha@redhat.com>
> > Signed-off-by: Liu Yuan <namei.unix@gmail.com>
> > ---
> >  block.c                   | 7 +++++++
> >  include/block/block.h     | 7 +++++++
> >  include/block/block_int.h | 3 +++
> >  3 files changed, 17 insertions(+)
> > 
> > diff --git a/block.c b/block.c
> > index c12b8de..22eb3e4 100644
> > --- a/block.c
> > +++ b/block.c
> > @@ -2152,6 +2152,13 @@ void bdrv_set_dev_ops(BlockDriverState *bs, const BlockDevOps *ops,
> >      bs->dev_opaque = opaque;
> >  }
> >  
> > +void bdrv_set_drv_ops(BlockDriverState *bs, const BlockDrvOps *ops,
> > +                      void *opaque)
> > +{
> > +    bs->drv_ops = ops;
> > +    bs->drv_opaque = opaque;
> 
> We need to be very carefull of the mix between these fields and the infamous
> bdrv_swap function.
> 
> Also I don't know if "driver operations" is the right name since the BlockDriver structure's
> callback could also be named "driver operations".
> 

BlockDrvierState has a "device operation" for callbacks from devices. So I
choose "driver operation". So any sugguestion for better name?

Thanks
Yuan