Re: [PATCH 3/5] add sg segment limitation info to device structure

[Greg KH <gregkh@suse.de>]

On Wed, Sep 26, 2007 at 05:58:01PM +0900, FUJITA Tomonori wrote:
> iommu code merges sg segments without considering lld's sg segment
> restrictions. iommu code can't access to the limitations because they
> are in request_queue. This patch adds max_segment_size to device
> structure. seg_boundary_mask will be added too later.
> 
> Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
> ---
>  include/linux/device.h |    7 +++++++
>  1 files changed, 7 insertions(+), 0 deletions(-)
> 
> diff --git a/include/linux/device.h b/include/linux/device.h
> index 3a38d1f..8046b60 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -443,6 +443,13 @@ struct device {
>  
>  	struct dma_coherent_mem	*dma_mem; /* internal for coherent mem
>  					     override */
> +
> +	/*
> +	 * a low level driver may set these to teach IOMMU code about
> +	 * sg limitations.
> +	 */
> +	unsigned int max_segment_size;

Does this really need to be here?  Can't it go into the bus specific
device that needs this?

thanks,

greg k-h