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Date: Tue, 29 Apr 2014 08:09:39 +0200
From: David Herrmann <dh.herrmann@...il.com>
To: Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc: "open list:HID CORE LAYER" <linux-input@...r.kernel.org>,
linux-kernel <linux-kernel@...r.kernel.org>,
Alexander Shiyan <shc_work@...l.ru>
Subject: Re: [PATCH] Input: implement managed polled input devices
Hi
On Tue, Apr 29, 2014 at 5:23 AM, Dmitry Torokhov
<dmitry.torokhov@...il.com> wrote:
> Managed resources are becoming more and more popular in drivers. Let's
> implement managed polled input devices, to complement managed regular input
> devices.
>
> Similarly to managed regular input devices only one new call
> devm_input_allocate_polled_device() is added and the rest of APIs is
> modified to work with both managed and non-managed devices.
>
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
> ---
> drivers/input/input-polldev.c | 113 +++++++++++++++++++++++++++++++++++++++++-
> include/linux/input-polldev.h | 3 ++
> 2 files changed, 115 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/input/input-polldev.c b/drivers/input/input-polldev.c
> index 4b19190..27961fc 100644
> --- a/drivers/input/input-polldev.c
> +++ b/drivers/input/input-polldev.c
> @@ -176,6 +176,90 @@ struct input_polled_dev *input_allocate_polled_device(void)
> }
> EXPORT_SYMBOL(input_allocate_polled_device);
>
> +struct input_polled_devres {
> + struct input_polled_dev *polldev;
> +};
> +
> +static int devm_input_polldev_match(struct device *dev, void *res, void *data)
> +{
> + struct input_polled_devres *devres = res;
> +
> + return devres->polldev == data;
> +}
> +
> +static void devm_input_polldev_release(struct device *dev, void *res)
> +{
> + struct input_polled_devres *devres = res;
> + struct input_polled_dev *polldev = devres->polldev;
> +
> + dev_dbg(dev, "%s: dropping reference/freeing %s\n",
> + __func__, dev_name(&polldev->input->dev));
> +
> + input_put_device(polldev->input);
> + kfree(polldev);
> +}
> +
> +static void devm_input_polldev_unregister(struct device *dev, void *res)
> +{
> + struct input_polled_devres *devres = res;
> + struct input_polled_dev *polldev = devres->polldev;
> +
> + dev_dbg(dev, "%s: unregistering device %s\n",
> + __func__, dev_name(&polldev->input->dev));
> + input_unregister_device(polldev->input);
> +
> + /*
> + * Note that we are still holding extra reference to the input
> + * device so it will stick around until devm_input_polldev_release()
> + * is called.
> + */
> +}
> +
> +/**
> + * devm_input_allocate_polled_device - allocate managed polled device
> + * @dev: device owning the polled device being created
> + *
> + * Returns prepared &struct input_polled_dev or %NULL.
> + *
> + * Managed polled input devices do not need to be explicitly unregistered
> + * or freed as it will be done automatically when owner device unbinds
> + * from * its driver (or binding fails). Once such managed polled device
> + * is allocated, it is ready to be set up and registered in the same
> + * fashion as regular polled input devices (using
> + * input_register_polled_device() function).
> + *
> + * If you want to manually unregister and free such managed polled devices,
> + * it can be still done by calling input_unregister_polled_device() and
> + * input_free_polled_device(), although it is rarely needed.
> + *
> + * NOTE: the owner device is set up as parent of input device and users
> + * should not override it.
> + */
> +struct input_polled_dev *devm_input_allocate_polled_device(struct device *dev)
> +{
> + struct input_polled_dev *polldev;
> + struct input_polled_devres *devres;
> +
> + devres = devres_alloc(devm_input_polldev_release, sizeof(*devres),
> + GFP_KERNEL);
> + if (!devres)
> + return NULL;
> +
> + polldev = input_allocate_polled_device();
> + if (!polldev) {
> + devres_free(devres);
> + return NULL;
> + }
> +
> + polldev->input->dev.parent = dev;
> + polldev->devres_managed = true;
> +
> + devres->polldev = polldev;
> + devres_add(dev, devres);
> +
> + return polldev;
> +}
> +
> /**
> * input_free_polled_device - free memory allocated for polled device
> * @dev: device to free
> @@ -186,7 +270,12 @@ EXPORT_SYMBOL(input_allocate_polled_device);
> void input_free_polled_device(struct input_polled_dev *dev)
> {
> if (dev) {
> - input_free_device(dev->input);
> + if (dev->devres_managed)
> + WARN_ON(devres_destroy(dev->input->dev.parent,
> + devm_input_polldev_release,
> + devm_input_polldev_match,
> + dev));
> + input_put_device(dev->input);
> kfree(dev);
> }
> }
> @@ -204,9 +293,19 @@ EXPORT_SYMBOL(input_free_polled_device);
> */
> int input_register_polled_device(struct input_polled_dev *dev)
> {
> + struct input_polled_devres *devres = NULL;
> struct input_dev *input = dev->input;
> int error;
>
> + if (dev->devres_managed) {
> + devres = devres_alloc(devm_input_polldev_unregister,
> + sizeof(*devres), GFP_KERNEL);
> + if (!devres)
> + return -ENOMEM;
> +
> + devres->polldev = dev;
Your error-paths in this function _must_ free "devres" via devres_free().
With this fixed:
Reviewed-by: David Herrmann <dh.herrmann@...il.com>
Thanks
David
> + }
> +
> input_set_drvdata(input, dev);
> INIT_DELAYED_WORK(&dev->work, input_polled_device_work);
>
> @@ -233,6 +332,12 @@ int input_register_polled_device(struct input_polled_dev *dev)
> */
> input_get_device(input);
>
> + if (dev->devres_managed) {
> + dev_dbg(input->dev.parent, "%s: registering %s with devres.\n",
> + __func__, dev_name(&input->dev));
> + devres_add(input->dev.parent, devres);
> + }
> +
> return 0;
> }
> EXPORT_SYMBOL(input_register_polled_device);
> @@ -247,6 +352,12 @@ EXPORT_SYMBOL(input_register_polled_device);
> */
> void input_unregister_polled_device(struct input_polled_dev *dev)
> {
> + if (dev->devres_managed)
> + WARN_ON(devres_destroy(dev->input->dev.parent,
> + devm_input_polldev_unregister,
> + devm_input_polldev_match,
> + dev));
> +
> input_unregister_device(dev->input);
> }
> EXPORT_SYMBOL(input_unregister_polled_device);
> diff --git a/include/linux/input-polldev.h b/include/linux/input-polldev.h
> index ce0b724..2465182 100644
> --- a/include/linux/input-polldev.h
> +++ b/include/linux/input-polldev.h
> @@ -48,9 +48,12 @@ struct input_polled_dev {
>
> /* private: */
> struct delayed_work work;
> +
> + bool devres_managed;
> };
>
> struct input_polled_dev *input_allocate_polled_device(void);
> +struct input_polled_dev *devm_input_allocate_polled_device(struct device *dev);
> void input_free_polled_device(struct input_polled_dev *dev);
> int input_register_polled_device(struct input_polled_dev *dev);
> void input_unregister_polled_device(struct input_polled_dev *dev);
> --
> 1.9.0
>
>
> --
> Dmitry
> --
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