On Fri, Jul 19, 2013 at 09:39:27AM +0100, Srinivas KANDAGATLA wrote:
> From: Srinivas Kandagatla <srinivas.kandagatla@xxxxxx>
>
> This patch adds user count to rc_dev structure, the reason to add this
> new member is to allow other code like lirc to open rc device directly.
> In the existing code, rc device is only opened by input subsystem which
> works ok if we have any input drivers to match. But in case like lirc
> where there will be no input driver, rc device will be never opened.
>
> Having this user count variable will be useful to allow rc device to be
> opened from code other than rc-main.
>
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxx>
> ---
> drivers/media/rc/rc-main.c | 11 +++++++++--
> include/media/rc-core.h | 1 +
> 2 files changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/rc/rc-main.c b/drivers/media/rc/rc-main.c
> index 1cf382a..e800b96 100644
> --- a/drivers/media/rc/rc-main.c
> +++ b/drivers/media/rc/rc-main.c
> @@ -702,15 +702,22 @@ EXPORT_SYMBOL_GPL(rc_keydown_notimeout);
> static int ir_open(struct input_dev *idev)
> {
> struct rc_dev *rdev = input_get_drvdata(idev);
> + int rval = 0;
>
> - return rdev->open(rdev);
> + if (!rdev->users++)
> + rval = rdev->open(rdev);
> +
> + if (rval)
> + rdev->users--;
> +
> + return rval;
This looks racey. Some locking is needed, I think rc_dev->lock should work
fine for this. Here and in the lirc code path too.
Sean
> }
>
> static void ir_close(struct input_dev *idev)
> {
> struct rc_dev *rdev = input_get_drvdata(idev);
>
> - if (rdev)
> + if (rdev && !--rdev->users)
> rdev->close(rdev);
> }
>
> diff --git a/include/media/rc-core.h b/include/media/rc-core.h
> index 06a75de..b42016a 100644
> --- a/include/media/rc-core.h
> +++ b/include/media/rc-core.h
> @@ -101,6 +101,7 @@ struct rc_dev {
> bool idle;
> u64 allowed_protos;
> u64 enabled_protocols;
> + u32 users;
> u32 scanmask;
> void *priv;
> spinlock_t keylock;
> --
> 1.7.6.5
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