| Message ID | 1374223167-4980-1-git-send-email-srinivas.kandagatla@st.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Jul 19, 2013 at 09:39:27AM +0100, Srinivas KANDAGATLA wrote: > From: Srinivas Kandagatla <srinivas.kandagatla@st.com> > > 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@st.com> > --- > 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 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 19/07/13 12:01, Sean Young wrote: >> + 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. thanks Sean, It makes sense, will fix this in v2. Srini > > Sean > >> } > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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; } 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;