[PATCH] iio: trigger: free trigger resource correctly

[PATCH] iio: trigger: free trigger resource correctly

[Alison Schofield]

Using iio_trigger_put() to free a trigger leads to release of
a resource we never held.  Replace with iio_trigger_free().

Signed-off-by: Alison Schofield <amsfield22@gmail.com>
---
Patches to use devm_* funcs are ready to follow this for
the interrupt & bfin-timer triggers.

 drivers/iio/trigger/iio-trig-interrupt.c          | 4 ++--
 drivers/iio/trigger/iio-trig-sysfs.c              | 2 +-
 drivers/staging/iio/trigger/iio-trig-bfin-timer.c | 4 ++--
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/trigger/iio-trig-interrupt.c b/drivers/iio/trigger/iio-trig-interrupt.c
index 572bc6f..b18e50d 100644
--- a/drivers/iio/trigger/iio-trig-interrupt.c
+++ b/drivers/iio/trigger/iio-trig-interrupt.c
@@ -84,7 +84,7 @@ static int iio_interrupt_trigger_probe(struct platform_device *pdev)
 error_free_trig_info:
 	kfree(trig_info);
 error_put_trigger:
-	iio_trigger_put(trig);
+	iio_trigger_free(trig);
 error_ret:
 	return ret;
 }
@@ -99,7 +99,7 @@ static int iio_interrupt_trigger_remove(struct platform_device *pdev)
 	iio_trigger_unregister(trig);
 	free_irq(trig_info->irq, trig);
 	kfree(trig_info);
-	iio_trigger_put(trig);
+	iio_trigger_free(trig);
 
 	return 0;
 }
diff --git a/drivers/iio/trigger/iio-trig-sysfs.c b/drivers/iio/trigger/iio-trig-sysfs.c
index 3dfab2b..202e8b8 100644
--- a/drivers/iio/trigger/iio-trig-sysfs.c
+++ b/drivers/iio/trigger/iio-trig-sysfs.c
@@ -174,7 +174,7 @@ static int iio_sysfs_trigger_probe(int id)
 	return 0;
 
 out2:
-	iio_trigger_put(t->trig);
+	iio_trigger_free(t->trig);
 free_t:
 	kfree(t);
 out1:
diff --git a/drivers/staging/iio/trigger/iio-trig-bfin-timer.c b/drivers/staging/iio/trigger/iio-trig-bfin-timer.c
index 9658f20..4e0b4ee 100644
--- a/drivers/staging/iio/trigger/iio-trig-bfin-timer.c
+++ b/drivers/staging/iio/trigger/iio-trig-bfin-timer.c
@@ -260,7 +260,7 @@ static int iio_bfin_tmr_trigger_probe(struct platform_device *pdev)
 out1:
 	iio_trigger_unregister(st->trig);
 out:
-	iio_trigger_put(st->trig);
+	iio_trigger_free(st->trig);
 	return ret;
 }
 
@@ -273,7 +273,7 @@ static int iio_bfin_tmr_trigger_remove(struct platform_device *pdev)
 		peripheral_free(st->t->pin);
 	free_irq(st->irq, st);
 	iio_trigger_unregister(st->trig);
-	iio_trigger_put(st->trig);
+	iio_trigger_free(st->trig);
 
 	return 0;
 }
-- 
2.1.4

Re: [PATCH] iio: trigger: free trigger resource correctly

[Dan Carpenter]

On Tue, Jan 17, 2017 at 07:00:28PM -0800, Alison Schofield wrote:
> Using iio_trigger_put() to free a trigger leads to release of
> a resource we never held.  Replace with iio_trigger_free().

They're basically the same except iio_trigger_put() puts the module and
the device and free only puts the device.

I've looked at this briefly, but I can't figure out how iio_trigger_get/
iio_trigger_put is supposed to be used.  There isn't any documentation.
I'm trying to review this code, but I can't figure out where we *are*
supposed to be doing the put.

For example, iio_device_unregister_trigger_consumer() takes a put, but
iio_device_register_trigger_consumer() doesn't do a get...  It's all
very confusing.

You seem like you know what's going on.  Can we get some documentation?

> 
> Signed-off-by: Alison Schofield <amsfield22@gmail.com>
> ---
> Patches to use devm_* funcs are ready to follow this for
> the interrupt & bfin-timer triggers.
> 
>  drivers/iio/trigger/iio-trig-interrupt.c          | 4 ++--
>  drivers/iio/trigger/iio-trig-sysfs.c              | 2 +-
>  drivers/staging/iio/trigger/iio-trig-bfin-timer.c | 4 ++--
>  3 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/iio/trigger/iio-trig-interrupt.c b/drivers/iio/trigger/iio-trig-interrupt.c
> index 572bc6f..b18e50d 100644
> --- a/drivers/iio/trigger/iio-trig-interrupt.c
> +++ b/drivers/iio/trigger/iio-trig-interrupt.c
> @@ -84,7 +84,7 @@ static int iio_interrupt_trigger_probe(struct platform_device *pdev)
>  error_free_trig_info:
>  	kfree(trig_info);
>  error_put_trigger:
> -	iio_trigger_put(trig);
> +	iio_trigger_free(trig);


We could rename this label.

regards,
dan carpenter

Re: [PATCH] iio: trigger: free trigger resource correctly

[Alison Schofield]

On Wed, Jan 18, 2017 at 12:56:29PM +0300, Dan Carpenter wrote:
> On Tue, Jan 17, 2017 at 07:00:28PM -0800, Alison Schofield wrote:
> > Using iio_trigger_put() to free a trigger leads to release of
> > a resource we never held.  Replace with iio_trigger_free().
> 
> They're basically the same except iio_trigger_put() puts the module and
> the device and free only puts the device.
> 
> I've looked at this briefly, but I can't figure out how iio_trigger_get/
> iio_trigger_put is supposed to be used.  There isn't any documentation.
> I'm trying to review this code, but I can't figure out where we *are*
> supposed to be doing the put.
> 
> For example, iio_device_unregister_trigger_consumer() takes a put, but
> iio_device_register_trigger_consumer() doesn't do a get...  It's all
> very confusing.
> 
> You seem like you know what's going on.  Can we get some documentation?
> 
Dan,
Although I'm comfortable within the bounds of this fix (pair the  
alloc & free's and do not _put the module resource we never _get'd) 
beyond that, not so much.  I'm just figuring it out myself.

linux-iio experts...pointers, help?

alisons


> > 
> > Signed-off-by: Alison Schofield <amsfield22@gmail.com>
> > ---
> > Patches to use devm_* funcs are ready to follow this for
> > the interrupt & bfin-timer triggers.
> > 
> >  drivers/iio/trigger/iio-trig-interrupt.c          | 4 ++--
> >  drivers/iio/trigger/iio-trig-sysfs.c              | 2 +-
> >  drivers/staging/iio/trigger/iio-trig-bfin-timer.c | 4 ++--
> >  3 files changed, 5 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/iio/trigger/iio-trig-interrupt.c b/drivers/iio/trigger/iio-trig-interrupt.c
> > index 572bc6f..b18e50d 100644
> > --- a/drivers/iio/trigger/iio-trig-interrupt.c
> > +++ b/drivers/iio/trigger/iio-trig-interrupt.c
> > @@ -84,7 +84,7 @@ static int iio_interrupt_trigger_probe(struct platform_device *pdev)
> >  error_free_trig_info:
> >  	kfree(trig_info);
> >  error_put_trigger:
> > -	iio_trigger_put(trig);
> > +	iio_trigger_free(trig);
> 
> 
> We could rename this label.
> 
> regards,
> dan carpenter
>