Re: [PATCH 1/3] dmaengine: add new dma API for max_segment_number

From: Koul, Vinod
Date: Wed Jun 01 2011 - 05:06:19 EST


On Thu, 2011-05-26 at 14:31 +0800, Shawn Guo wrote:
> Like dma_set(get)_max_seg_size for max_segment_size, the patch adds
> max_segment_number into device_dma_parameters and creates the
> corresponding dmaengine API dma_set(get)_max_seg_number for it.
>
> Signed-off-by: Shawn Guo <shawn.guo@xxxxxxxxxx>
> ---
> include/linux/device.h | 1 +
> include/linux/dma-mapping.h | 15 +++++++++++++++
> 2 files changed, 16 insertions(+), 0 deletions(-)
Can you explain me why this change is required, the patch description
isn't helping for this.

If you satisfy me with above then I am okay with it, but I need ACK from
Dan before applying...

~Vinod

>
> diff --git a/include/linux/device.h b/include/linux/device.h
> index c66111a..44cb2528 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -487,6 +487,7 @@ struct device_dma_parameters {
> * sg limitations.
> */
> unsigned int max_segment_size;
> + unsigned int max_segment_number;
> unsigned long segment_boundary_mask;
> };
>
> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index ba8319a..fd314f4 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -131,6 +131,21 @@ static inline unsigned int dma_set_max_seg_size(struct device *dev,
> return -EIO;
> }
>
> +static inline unsigned int dma_get_max_seg_number(struct device *dev)
> +{
> + return dev->dma_parms ? dev->dma_parms->max_segment_number : 1;
> +}
> +
> +static inline unsigned int dma_set_max_seg_number(struct device *dev,
> + unsigned int number)
> +{
> + if (dev->dma_parms) {
> + dev->dma_parms->max_segment_number = number;
> + return 0;
> + } else
> + return -EIO;
> +}
> +
> static inline unsigned long dma_get_seg_boundary(struct device *dev)
> {
> return dev->dma_parms ?



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