On Tuesday 16 September 2008, [EMAIL PROTECTED] wrote:
> From: Ming Lei <[EMAIL PROTECTED]>
>
> The status[] is part of uvc_device structure. We can't make sure
> the address of status is at a cache-line boundary in all archs,so
> status[] might share a cache-line with some fields in uvc_structure.
> This can lead to some cache coherence
> issues(http://lwn.net/Articles/2265/). Use dynamically allocated buffer
> instead.
Thanks for fixing this.
> Signed-off-by: Ming Lei <[EMAIL PROTECTED]>
Acked-by: Laurent Pinchart <[EMAIL PROTECTED]>
Mauro, can you please apply the patch ?
> ---
> drivers/media/video/uvc/uvc_status.c | 11 +++++++++--
> drivers/media/video/uvc/uvcvideo.h | 4 +++-
> 2 files changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/media/video/uvc/uvc_status.c
> b/drivers/media/video/uvc/uvc_status.c index 75e678a..5d60b26 100644
> --- a/drivers/media/video/uvc/uvc_status.c
> +++ b/drivers/media/video/uvc/uvc_status.c
> @@ -177,9 +177,15 @@ int uvc_status_init(struct uvc_device *dev)
>
> uvc_input_init(dev);
>
> + dev->status = kzalloc(UVC_MAX_STATUS_SIZE, GFP_KERNEL);
> + if (dev->status == NULL)
> + return -ENOMEM;
> +
> dev->int_urb = usb_alloc_urb(0, GFP_KERNEL);
> - if (dev->int_urb == NULL)
> + if (dev->int_urb == NULL) {
> + kfree(dev->status);
> return -ENOMEM;
> + }
>
> pipe = usb_rcvintpipe(dev->udev, ep->desc.bEndpointAddress);
>
> @@ -192,7 +198,7 @@ int uvc_status_init(struct uvc_device *dev)
> interval = fls(interval) - 1;
>
> usb_fill_int_urb(dev->int_urb, dev->udev, pipe,
> - dev->status, sizeof dev->status, uvc_status_complete,
> + dev->status, UVC_MAX_STATUS_SIZE, uvc_status_complete,
> dev, interval);
>
> return usb_submit_urb(dev->int_urb, GFP_KERNEL);
> @@ -202,6 +208,7 @@ void uvc_status_cleanup(struct uvc_device *dev)
> {
> usb_kill_urb(dev->int_urb);
> usb_free_urb(dev->int_urb);
> + kfree(dev->status);
> uvc_input_cleanup(dev);
> }
>
> diff --git a/drivers/media/video/uvc/uvcvideo.h
> b/drivers/media/video/uvc/uvcvideo.h index bafe340..9a6bc1a 100644
> --- a/drivers/media/video/uvc/uvcvideo.h
> +++ b/drivers/media/video/uvc/uvcvideo.h
> @@ -303,6 +303,8 @@ struct uvc_xu_control {
> #define UVC_MAX_FRAME_SIZE (16*1024*1024)
> /* Maximum number of video buffers. */
> #define UVC_MAX_VIDEO_BUFFERS 32
> +/* Maximum status buffer size in bytes of interrupt URB. */
> +#define UVC_MAX_STATUS_SIZE 16
>
> #define UVC_CTRL_CONTROL_TIMEOUT 300
> #define UVC_CTRL_STREAMING_TIMEOUT 1000
> @@ -634,7 +636,7 @@ struct uvc_device {
> /* Status Interrupt Endpoint */
> struct usb_host_endpoint *int_ep;
> struct urb *int_urb;
> - __u8 status[16];
> + __u8 *status;
> struct input_dev *input;
>
> /* Video Streaming interfaces */
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