On Wed, Sep 04, 2013 at 02:18:30PM +0900, Chanwoo Choi wrote: > On 09/04/2013 10:16 AM, Greg KH wrote: > > On Wed, Sep 04, 2013 at 09:17:02AM +0900, Chanwoo Choi wrote: > >> On 09/04/2013 12:57 AM, Greg KH wrote: > >>> On Mon, Sep 02, 2013 at 10:13:44AM +0900, Chanwoo Choi wrote: > >>>> Hi Greg, > >>>> > >>>> On 09/02/2013 09:40 AM, Greg KH wrote: > >>>>> On Mon, Sep 02, 2013 at 09:20:08AM +0900, Chanwoo Choi wrote: > >>>>>> This patch remove extcon_dev_register()'s second parameter which means > >>>>>> the pointer of parent device to simplify prototype of this function. > >>>>> > >>>>> No, please don't. You want the parent to be passed in, as the core > >>>>> needs it when it is registered with the system, otherwise it will not > >>>>> show up in sysfs properly (i.e. you can't set it afterwards.) > >>>> > >>>> Currently, each extcon driver have allocated memory for extcon device > >>>> by using devm_kzalloc() in each extcon device driver. > >>> > >>> That seems backwards, the extcon core should be the one doing the > >>> allocation, and ownership of the device, like all other subsystem cores > >>> do. That makes the driver logic much simpler, and the lifetime > >>> ownership correct (i.e. what happens when a device is unbound from a > >>> driver by userspace? The driver can't control the device memory > >>> anymore...) > >>> > >> > >> OK, > >> The extcon core will control memory allocation instead of extcon device > >> driver > >> as following. > >> - devm_extcon_allocate_device(struct device *dev) > > > > Huh? Why do you need a devm allocator? This is a "real" child device, > > just create it with a "extcon_create_device()" or some such call, like > > all other busses do? > > I refer Input/IIO subsystem to check the process of device registration. > Input subsystem has following functions for memory allocation of input device > and input device registration. > > Input subsystem > - struct input_dev *devm_input_allocate_device(struct device *device) > - struct input_dev *input_allocate_device(void) > - int input_register_device(struct input_dev *dev) > drivers/input/input.c > > devm_input_allocate_device()/input_allocate_device() can allocate > memory for input device in input core. And then created input device > pass input_register_device() as parameter. > > So, input device driver haven't executed kmalloc() or devm_kmalloc() > to allocate memory of input device by using input_allocate_device()/ > devm_input_allocate_device(). > > > Also,IIO subsystem has separate iio_device_alloc() function > to allocate memory for iio device. But IIO subsystem hasn't > "devm_" allocator. So, If iio device driver fail initialization > in *_probe, should execute iio_device_free() to free allocated memory. > > IIO Subsystem > - iio_device_alloc(int sizeof_priv) > - iio_device_register(struct iio_dev *indio_dev); > drivers/iio/industrialio-core.c > > > So, I think extcon subsystem need > extcon_allocate_device()/devm_extcon_allocate_device() > to allocate for memory extcon device. To implement > devm_extcon_allocate_device() function > , extcon subsystem need extcon_allocate_device() because > devm_extcon_allocate_device() > must call extcon_allocate_device for memory allocation. > > If extcon_allocate_device()/devm_extcon_allocate_device() is implemented to > extcon core, > I think extcon core can control the memory operation of extcon device. > > EXTCON Subsystem > - devm_extcon_allocate_device(struct device *dev) > - extcon_allocate_device(void) > - extcon_dev_register(struct extcon_dev *edev) > > If I'm wrong, please correct me. Thanks.
No, you are totally correct, I was wrong, nevermind, continue on doing a great job, my mistake :) greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
