On 04/27/2016 03:52 AM, Kevin Wolf wrote:
> This is a function that simply calls into the block driver for doing a
> read, providing the byte granularity interface we want to eventually
> have everywhere, and using whatever interface that driver supports.
>
> For now, this is just a wrapper for calling bs->drv->bdrv_co_readv().
>
> Signed-off-by: Kevin Wolf <kw...@redhat.com>
> ---
> block/io.c | 30 +++++++++++++++++++++++-------
> 1 file changed, 23 insertions(+), 7 deletions(-)
>
> diff --git a/block/io.c b/block/io.c
> index a7dbf85..586a46a 100644
> --- a/block/io.c
> +++ b/block/io.c
> @@ -800,6 +800,21 @@ int bdrv_pwrite_sync(BlockDriverState *bs, int64_t
> offset,
> return 0;
> }
>
> +static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs,
> + uint64_t offset, uint64_t bytes,
> + QEMUIOVector *qiov, int flags)
> +{
> + BlockDriver *drv = bs->drv;
> + int64_t sector_num = offset >> BDRV_SECTOR_BITS;
> + unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS;
> +
> + assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
> + assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
> + assert((bytes >> BDRV_SECTOR_BITS) <= BDRV_REQUEST_MAX_SECTORS);So for now it is still enforcing 512-byte alignment, but gives us the opportunity to relax things later. Reviewed-by: Eric Blake <ebl...@redhat.com> -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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