C++ devres_free函数代码示例

static struct regulator *_devm_regulator_get(struct device *dev, const char *id,
					     int get_type)
{
	struct regulator **ptr, *regulator;

	ptr = devres_alloc(devm_regulator_release, sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
		return ERR_PTR(-ENOMEM);

	switch (get_type) {
	case NORMAL_GET:
		regulator = regulator_get(dev, id);
		break;
	case EXCLUSIVE_GET:
		regulator = regulator_get_exclusive(dev, id);
		break;
	case OPTIONAL_GET:
		regulator = regulator_get_optional(dev, id);
		break;
	default:
		regulator = ERR_PTR(-EINVAL);
	}

	if (!IS_ERR(regulator)) {
		*ptr = regulator;
		devres_add(dev, ptr);
	} else {
		devres_free(ptr);
	}

	return regulator;
}

struct dentry* devm_hello_create_file(
		struct device *dev,
		const char *name,
		umode_t mode,
		struct dentry *parent,
		void *data,
		const struct file_operations* fops)
{
	struct dentry *pfile = NULL;
	void *ptr = NULL;

	if(!fops || !name || name[0] == '\0')
		return NULL;

	ptr = devres_alloc(devm_hello_release, 0, GFP_KERNEL);
	if (!ptr)
		return NULL;

	pfile = debugfs_create_file(name, mode, parent, data, fops);
	if (pfile) {
		devres_add(dev, ptr);
	} else {
		devres_free(ptr);
	}

	return pfile;
}

/**
 * devm_regulator_register_supply_alias - Resource managed
 * regulator_register_supply_alias()
 *
 * @dev: device that will be given as the regulator "consumer"
 * @id: Supply name or regulator ID
 * @alias_dev: device that should be used to lookup the supply
 * @alias_id: Supply name or regulator ID that should be used to lookup the
 * supply
 *
 * The supply alias will automatically be unregistered when the source
 * device is unbound.
 */
int devm_regulator_register_supply_alias(struct device *dev, const char *id,
					 struct device *alias_dev,
					 const char *alias_id)
{
	struct regulator_supply_alias_match *match;
	int ret;

	match = devres_alloc(devm_regulator_destroy_supply_alias,
			   sizeof(struct regulator_supply_alias_match),
			   GFP_KERNEL);
	if (!match)
		return -ENOMEM;

	match->dev = dev;
	match->id = id;

	ret = regulator_register_supply_alias(dev, id, alias_dev, alias_id);
	if (ret < 0) {
		devres_free(match);
		return ret;
	}

	devres_add(dev, match);

	return 0;
}

/**
 * devres_release - Find a device resource and destroy it, calling release
 * @dev: Device to find resource from
 * @release: Look for resources associated with this release function
 * @match: Match function (optional)
 * @match_data: Data for the match function
 *
 * Find the latest devres of @dev associated with @release and for
 * which @match returns 1.  If @match is NULL, it's considered to
 * match all.  If found, the resource is removed atomically, the
 * release function called and the resource freed.
 *
 * RETURNS:
 * 0 if devres is found and freed, -ENOENT if not found.
 */
int devres_release(struct device *dev, dr_release_t release,
		   dr_match_t match, void *match_data)
{
	void *res;

	res = devres_remove(dev, release, match, match_data);
	if (unlikely(!res))
		return -ENOENT;

	(*release)(dev, res);
	devres_free(res);
	return 0;
}

/**
 * input_register_polled_device - register polled device
 * @dev: device to register
 *
 * The function registers previously initialized polled input device
 * with input layer. The device should be allocated with call to
 * input_allocate_polled_device(). Callers should also set up poll()
 * method and set up capabilities (id, name, phys, bits) of the
 * corresponding input_dev structure.
 */
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;
	}

	input_set_drvdata(input, dev);
	INIT_DELAYED_WORK(&dev->work, input_polled_device_work);

	if (!dev->poll_interval)
		dev->poll_interval = 500;
	if (!dev->poll_interval_max)
		dev->poll_interval_max = dev->poll_interval;

	input->open = input_open_polled_device;
	input->close = input_close_polled_device;

	input->dev.groups = input_polldev_attribute_groups;

	error = input_register_device(input);
	if (error) {
		devres_free(devres);
		return error;
	}

	/*
	 * Take extra reference to the underlying input device so
	 * that it survives call to input_unregister_polled_device()
	 * and is deleted only after input_free_polled_device()
	 * has been invoked. This is needed to ease task of freeing
	 * sparse keymaps.
	 */
	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;
}

struct clk *devm_clk_get(struct device *dev, const char *id)
{
	struct clk **ptr, *clk;

	ptr = devres_alloc(devm_clk_release, sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
		return ERR_PTR(-ENOMEM);

	clk = clk_get(dev, id);
	if (!IS_ERR(clk)) {
		*ptr = clk;
		devres_add(dev, ptr);
	} else {
		devres_free(ptr);
	}

	return clk;
}

/**
 * devm_iio_fifo_allocate - Resource-managed iio_kfifo_allocate()
 * @dev:		Device to allocate kfifo buffer for
 *
 * RETURNS:
 * Pointer to allocated iio_buffer on success, NULL on failure.
 */
struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev)
{
	struct iio_buffer **ptr, *r;

	ptr = devres_alloc(devm_iio_kfifo_release, sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
		return NULL;

	r = iio_kfifo_allocate();
	if (r) {
		*ptr = r;
		devres_add(dev, ptr);
	} else {
		devres_free(ptr);
	}

	return r;
}

void *devm_memremap(struct device *dev, resource_size_t offset,
		size_t size, unsigned long flags)
{
	void **ptr, *addr;

	ptr = devres_alloc(devm_memremap_release, sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
		return NULL;

	addr = memremap(offset, size, flags);
	if (addr) {
		*ptr = addr;
		devres_add(dev, ptr);
	} else
		devres_free(ptr);

	return addr;
}

/**
 * devm_ioremap_wc - Managed ioremap_wc()
 * @dev: Generic device to remap IO address for
 * @offset: BUS offset to map
 * @size: Size of map
 *
 * Managed ioremap_wc().  Map is automatically unmapped on driver detach.
 */
void __iomem *devm_ioremap_wc(struct device *dev, resource_size_t offset,
			      resource_size_t size)
{
	void __iomem **ptr, *addr;

	ptr = devres_alloc(devm_ioremap_release, sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
		return NULL;

	addr = ioremap_wc(offset, size);
	if (addr) {
		*ptr = addr;
		devres_add(dev, ptr);
	} else
		devres_free(ptr);

	return addr;
}

/**
 * devm_snd_soc_register_card - resource managed card registration
 * @dev: Device used to manage card
 * @card: Card to register
 *
 * Register a card with automatic unregistration when the device is
 * unregistered.
 */
int devm_snd_soc_register_card(struct device *dev, struct snd_soc_card *card)
{
	struct snd_soc_card **ptr;
	int ret;

	ptr = devres_alloc(devm_card_release, sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
		return -ENOMEM;

	ret = snd_soc_register_card(card);
	if (ret == 0) {
		*ptr = card;
		devres_add(dev, ptr);
	} else {
		devres_free(ptr);
	}

	return ret;
}

struct kobject *devm_kobject_create_and_add(struct device *dev, const char *name, struct kobject *parent)
{
	struct kobject **ptr, *kobj;

	ptr = devres_alloc(devm_kobject_release, sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
		return ERR_PTR(-ENOMEM);

	kobj = kobject_create_and_add("kobject_example", &dev->kobj);
	if (kobj) {
		*ptr = kobj;
		devres_add(dev, ptr);
	}
	else {
		devres_free(ptr);
	}

	return kobj;
}

static int snd_devm_add_child(struct device *dev, struct device *child)
{
	struct device **dr;
	int ret;

	dr = devres_alloc(snd_devm_unregister_child, sizeof(*dr), GFP_KERNEL);
	if (!dr)
		return -ENOMEM;

	ret = device_add(child);
	if (ret) {
		devres_free(dr);
		return ret;
	}

	*dr = child;
	devres_add(dev, dr);

	return 0;
}

/**
 * devm_snd_dmaengine_pcm_register - resource managed dmaengine PCM registration
 * @dev: The parent device for the PCM device
 * @config: Platform specific PCM configuration
 * @flags: Platform specific quirks
 *
 * Register a dmaengine based PCM device with automatic unregistration when the
 * device is unregistered.
 */
int devm_snd_dmaengine_pcm_register(struct device *dev,
	const struct snd_dmaengine_pcm_config *config, unsigned int flags)
{
	struct device **ptr;
	int ret;

	ptr = devres_alloc(devm_dmaengine_pcm_release, sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
		return -ENOMEM;

	ret = snd_dmaengine_pcm_register(dev, config, flags);
	if (ret == 0) {
		*ptr = dev;
		devres_add(dev, ptr);
	} else {
		devres_free(ptr);
	}

	return ret;
}

/**
 * devm_snd_soc_register_platform - resource managed platform registration
 * @dev: Device used to manage platform
 * @platform_drv: platform to register
 *
 * Register a platform driver with automatic unregistration when the device is
 * unregistered.
 */
int devm_snd_soc_register_platform(struct device *dev,
			const struct snd_soc_platform_driver *platform_drv)
{
	struct device **ptr;
	int ret;

	ptr = devres_alloc(devm_platform_release, sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
		return -ENOMEM;

	ret = snd_soc_register_platform(dev, platform_drv);
	if (ret == 0) {
		*ptr = dev;
		devres_add(dev, ptr);
	} else {
		devres_free(ptr);
	}

	return ret;
}

static int bcm2835_devm_add_vchi_ctx(struct device *dev)
{
	struct bcm2835_vchi_ctx *vchi_ctx;
	int ret;

	vchi_ctx = devres_alloc(bcm2835_devm_free_vchi_ctx, sizeof(*vchi_ctx),
				GFP_KERNEL);
	if (!vchi_ctx)
		return -ENOMEM;

	ret = bcm2835_new_vchi_ctx(dev, vchi_ctx);
	if (ret) {
		devres_free(vchi_ctx);
		return ret;
	}

	devres_add(dev, vchi_ctx);

	return 0;
}