Re: [PATCHv2 3/6] uvc gadget: switch to v4l2 core locking

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Hans,

Thank you for the patch.

On Tuesday 17 February 2015 09:44:06 Hans Verkuil wrote:
> From: Hans Verkuil <hans.verkuil@cisco.com>
> 
> Switch this driver over to the V4L2 core locking mechanism in preparation
> for switching to unlocked_ioctl. Suggested by Laurent Pinchart.
> 
> This patch introduces a new mutex at the struct uvc_video level and
> drops the old mutex at the queue level. The new lock is now used for all
> ioctl locking and in the release file operation (the driver always has
> to take care of locking in file operations, the core only serializes
> ioctls).

The patch also drops locking in the mmap and get_unmapped_area functions, 
shouldn't you mention it in the commit message ? Or possibly split that change 
to a separate patch, as that's a bugfix by itself (taking the queue lock there 
creates a possible AB-BA deadlock).

> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
>  drivers/usb/gadget/function/f_uvc.c     |  2 +
>  drivers/usb/gadget/function/uvc.h       |  1 +
>  drivers/usb/gadget/function/uvc_queue.c | 79 +++++-------------------------
>  drivers/usb/gadget/function/uvc_queue.h |  4 +-
>  drivers/usb/gadget/function/uvc_v4l2.c  |  3 +-
>  drivers/usb/gadget/function/uvc_video.c |  3 +-
>  6 files changed, 22 insertions(+), 70 deletions(-)

-- 
Regards,

Laurent Pinchart