Re: [Qemu-devel] [PATCHv5] block/get_block_status: avoid redundant callouts on raw devices

[Peter Lieven]

On 07.10.2013 10:25, Paolo Bonzini wrote:
> Il 07/10/2013 07:59, Peter Lieven ha scritto:
> > if a raw device like an iscsi target or host device is used
> > the current implementation makes a second call out to get
> > the block status of bs->file.
> >
> > Signed-off-by: Peter Lieven <address@hidden>
> > ---
> > v5: add a generic get_lba_status function in the raw driver which
> >      adds the BDRV_BLOCK_RAW flag. bdrv_co_get_block_status will
> >      handle the callout to bs->file then.
> >
> > v4: use a flag to detect the raw driver instead of the strncmp
> >      hack
> >
> >   block.c               |    4 ++++
> >   block/raw_bsd.c       |    3 ++-
> >   include/block/block.h |    4 ++++
> >   3 files changed, 10 insertions(+), 1 deletion(-)
> >
> > diff --git a/block.c b/block.c
> > index 93e113a..38a589e 100644
> > --- a/block.c
> > +++ b/block.c
> > @@ -3147,6 +3147,10 @@ static int64_t coroutine_fn 
> > bdrv_co_get_block_status(BlockDriverState *bs,
> >           return ret;
> >       }
> >   
> > +    if (ret & BDRV_BLOCK_RAW) {
> > +        return bdrv_get_block_status(bs->file, sector_num, nb_sectors, pnum);
> Strictly speaking, this should probably do something like this:
>
>    assert(ret & BDRV_BLOCK_OFFSET_VALID);
>    return bdrv_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS,
>                                 nb_sectors, pnum);
shouldn't the last line be:

  return bdrv_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS,
                               *pnum, pnum);


This would of course require *pnum = nb_sectors in raw_co_get_block_status
?