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Commit a31a4055 authored by Ming Lei's avatar Ming Lei Committed by Mauro Carvalho Chehab
Browse files

V4L/DVB:usbvideo:don't use part of buffer for USB transfer #4 

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.

Signed-off-by: default avatarMing Lei <tom.leiming@gmail.com>
Acked-by: default avatarLaurent Pinchart <laurent.pinchart@skynet.be>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent d63beb9e

drivers/media/video/uvc/uvc_status.c

+9 −2
Original line number Diff line number Diff line
@@ -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);

}

drivers/media/video/uvc/uvcvideo.h

+3 −1
Original line number Diff line number Diff line
@@ -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 */