Re: [PATCH] virtio_blk: add block topology support

[Rusty Russell <rusty@rustcorp.com.au>]

On Sat, 30 Jan 2010 05:31:58 am Christoph Hellwig wrote:
> Allow reading various alignment values from the config page.  This
> allows the guest to much better align I/O requests depending on the
> storage topology.
> 
> Note that the formats for the config values appear a bit messed up,
> but we follow the formats used by ATA and SCSI so they are expected in
> the storage world.

I bow to your expertise on that.  My only query is the __u16 for min_io_size; is that likely to restrict us?

Also, patch seems to be based on a prior one?

>  	/* Use topology information if available */
> -	err = virtio_config_val(vdev, VIRTIO_BLK_F_BLK_TOPOLOGY,
> +	err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
> +			offsetof(struct virtio_blk_config, physical_block_exp),
> +			&physical_block_exp);

Thanks,
Rusty.