Re: [PATCH 03/15] Input: synaptics-rmi4 - don't free devices directly

[Courtney Cavin <courtney.cavin@sonymobile.com>]

On Wed, Feb 05, 2014 at 12:08:24AM +0100, Christopher Heiny wrote:
> On 01/23/2014 04:00 PM, Courtney Cavin wrote:
> > Devices use a kobject to manage references, do not delete the memory
> > while still referenced.  Instead, call put_device() to release the
> > reference.
> 
> This is an interesting idea, but it should be done consistently for all 
> the device types.
> 

This is not an idea, just a bugfix.  The kernel will segfault on failure
in which results in the kfree().  I didn't notice any other
device_register() calls which have this particular issue, but I might
have missed something.

> >
> > Cc: Christopher Heiny <cheiny@synaptics.com>
> > Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > Signed-off-by: Courtney Cavin <courtney.cavin@sonymobile.com>
> > ---
> >   drivers/input/rmi4/rmi_bus.c    | 8 +++++---
> >   drivers/input/rmi4/rmi_driver.c | 6 +-----
> >   2 files changed, 6 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/input/rmi4/rmi_bus.c b/drivers/input/rmi4/rmi_bus.c
> > index 8a939f3..cd7bfbd 100644
> > --- a/drivers/input/rmi4/rmi_bus.c
> > +++ b/drivers/input/rmi4/rmi_bus.c
> > @@ -94,8 +94,7 @@ int rmi_register_transport_device(struct rmi_transport_dev *xport)
> >   		return -EINVAL;
> >   	}
> >
> > -	rmi_dev = devm_kzalloc(xport->dev,
> > -				sizeof(struct rmi_device), GFP_KERNEL);
> > +	rmi_dev = kzalloc(sizeof(struct rmi_device), GFP_KERNEL);
> >   	if (!rmi_dev)
> >   		return -ENOMEM;
> >
> > @@ -112,8 +111,10 @@ int rmi_register_transport_device(struct rmi_transport_dev *xport)
> >   	rmi_physical_setup_debugfs(rmi_dev);
> >
> >   	error = device_register(&rmi_dev->dev);
> > -	if (error)
> > +	if (error) {
> > +		put_device(&rmi_dev->dev);
> >   		return error;
> > +	}
> >
> >   	dev_dbg(xport->dev, "%s: Registered %s as %s.\n", __func__,
> >   		pdata->sensor_name, dev_name(&rmi_dev->dev));
> > @@ -240,6 +241,7 @@ int rmi_register_function(struct rmi_function *fn)
> >   		dev_err(&rmi_dev->dev,
> >   			"Failed device_register function device %s\n",
> >   			dev_name(&fn->dev));
> > +		put_device(&fn->dev);
> >   		goto error_exit;
> >   	}
> >
> > diff --git a/drivers/input/rmi4/rmi_driver.c b/drivers/input/rmi4/rmi_driver.c
> > index 5c6379c..4965589 100644
> > --- a/drivers/input/rmi4/rmi_driver.c
> > +++ b/drivers/input/rmi4/rmi_driver.c
> > @@ -557,15 +557,11 @@ static int create_function(struct rmi_device *rmi_dev,
> >
> >   	error = rmi_register_function(fn);
> >   	if (error)
> > -		goto err_free_mem;
> > +		return error;
> >
> >   	list_add_tail(&fn->node, &data->function_list);
> >
> >   	return 0;
> > -
> > -err_free_mem:
> > -	kfree(fn);
> > -	return error;
> >   }
> >
> >   /*
> >