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

Greg KH
2007-09-26T16:13:03Z

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