Gitweb: http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=a31a40...
Commit: a31a4055473bf0a7b2b06cb2262347200d0711e1
Parent: d63beb9ef004ff9587b3c466361276254d57d7a7
Author: Ming Lei <tom.leiming@gmail.com>
AuthorDate: Tue Sep 16 03:32:20 2008 -0300
Committer: Mauro Carvalho Chehab <mchehab@redhat.com>
CommitDate: Sun Oct 12 09:37:08 2008 -0200
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: Ming Lei <tom.leiming@gmail.com>
Acked-by: Laurent Pinchart <laurent.pinchart@skynet.be>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
---
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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