Re: [PATCH v2] media: uvcvideo: Do not alloc dev->status

[Sergey Senozhatsky <senozhatsky@chromium.org>]

On (22/12/14 14:37), Ricardo Ribalda wrote:
[..]
> +struct uvc_status_streaming {
> +	u8	button;
> +} __packed;
> +
> +struct uvc_status_control {
> +	u8	bSelector;
> +	u8	bAttribute;
> +	u8	bValue[11];
> +} __packed;
> +
> +struct uvc_status {
> +	u8	bStatusType;
> +	u8	bOriginator;
> +	u8	bEvent;
> +	union {
> +		struct uvc_status_control control;
> +		struct uvc_status_streaming streaming;
> +	};
> +} __packed;
> +
>  struct uvc_device {
>  	struct usb_device *udev;
>  	struct usb_interface *intf;
> @@ -559,7 +579,7 @@ struct uvc_device {
>  	/* Status Interrupt Endpoint */
>  	struct usb_host_endpoint *int_ep;
>  	struct urb *int_urb;
> -	u8 *status;
> +
>  	struct input_dev *input;
>  	char input_phys[64];
>  
> @@ -572,6 +592,12 @@ struct uvc_device {
>  	} async_ctrl;
>  
>  	struct uvc_entity *gpio_unit;
> +
> +	/*
> +	 * Ensure that status is aligned, making it safe to use with
> +	 * non-coherent DMA.
> +	 */
> +	struct uvc_status status __aligned(ARCH_KMALLOC_MINALIGN);

	____cacheline_aligned ?

I don't see anyone using ARCH_KMALLOC_MINALIGN except for slab.h