Re: [PATCH 10/29] drivers: add DRIVER_HAS_OWN_IOMMU_MANAGER flag

[Marek Szyprowski <m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>]

Hi Greg,

On 2014-08-05 12:47, Marek Szyprowski wrote:
> This patch adds a new flags for device drivers. This flag instructs
> kernel that the device driver does it own management of IOMMU assisted
> IO address space translations, so no default dma-mapping structures
> should be initialized.
>
> Signed-off-by: Marek Szyprowski <m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> ---
>   include/linux/device.h | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/include/linux/device.h b/include/linux/device.h
> index 5f4ff02..2e62371 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -253,6 +253,8 @@ struct device_driver {
>   
>   /* disables bind/unbind via sysfs */
>   #define DRIVER_SUPPRESS_BIND_ATTRS	(1 << 0)
> +/* driver uses own methods to manage IO address space */
> +#define DRIVER_HAS_OWN_IOMMU_MANAGER	(1 << 1)
>   
>   extern int __must_check driver_register(struct device_driver *drv);
>   extern void driver_unregister(struct device_driver *drv);

Could you comment if the approach of using flags in the struct driver
could be accepted? I've converted suppress_bind_attrs entry to flags to
avoid extending the structure, please see patch "[PATCH 05/29] drivers:
convert suppress_bind_attrs parameter into flags".

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland