Commit 39ef3112 authored by Guenter Roeck's avatar Guenter Roeck Committed by Greg Kroah-Hartman
Browse files

driver core: Introduce device_create_groups 



device_create_groups lets callers create devices as well as associated
sysfs attributes with a single call. This avoids race conditions seen
if sysfs attributes on new devices are created later.

[fixed up comment block placement and add checks for printk buffer
formats - gregkh]

Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 388a8c35

drivers/base/core.c

+83 −28
Original line number Diff line number Diff line
@@ -1667,34 +1667,11 @@ static void device_create_release(struct device *dev) 
	kfree(dev);

}



/**

 * device_create_vargs - creates a device and registers it with sysfs

 * @class: pointer to the struct class that this device should be registered to

 * @parent: pointer to the parent struct device of this new device, if any

 * @devt: the dev_t for the char device to be added

 * @drvdata: the data to be added to the device for callbacks

 * @fmt: string for the device's name

 * @args: va_list for the device's name

 *

 * This function can be used by char device classes.  A struct device

 * will be created in sysfs, registered to the specified class.

 *

 * A "dev" file will be created, showing the dev_t for the device, if

 * the dev_t is not 0,0.

 * If a pointer to a parent struct device is passed in, the newly created

 * struct device will be a child of that device in sysfs.

 * The pointer to the struct device will be returned from the call.

 * Any further sysfs files that might be required can be created using this

 * pointer.

 *

 * Returns &struct device pointer on success, or ERR_PTR() on error.

 *

 * Note: the struct class passed to this function must have previously

 * been created with a call to class_create().

 */

struct device *device_create_vargs(struct class *class, struct device *parent,

				   dev_t devt, void *drvdata, const char *fmt,

				   va_list args)

static struct device *

device_create_groups_vargs(struct class *class, struct device *parent,

			   dev_t devt, void *drvdata,

			   const struct attribute_group **groups,

			   const char *fmt, va_list args)

{

	struct device *dev = NULL;

	int retval = -ENODEV;
@@ -1711,6 +1688,7 @@ struct device *device_create_vargs(struct class *class, struct device *parent, 
	dev->devt = devt;

	dev->class = class;

	dev->parent = parent;

	dev->groups = groups;

	dev->release = device_create_release;

	dev_set_drvdata(dev, drvdata);
@@ -1728,6 +1706,39 @@ error: 
	put_device(dev);

	return ERR_PTR(retval);

}



/**

 * device_create_vargs - creates a device and registers it with sysfs

 * @class: pointer to the struct class that this device should be registered to

 * @parent: pointer to the parent struct device of this new device, if any

 * @devt: the dev_t for the char device to be added

 * @drvdata: the data to be added to the device for callbacks

 * @fmt: string for the device's name

 * @args: va_list for the device's name

 *

 * This function can be used by char device classes.  A struct device

 * will be created in sysfs, registered to the specified class.

 *

 * A "dev" file will be created, showing the dev_t for the device, if

 * the dev_t is not 0,0.

 * If a pointer to a parent struct device is passed in, the newly created

 * struct device will be a child of that device in sysfs.

 * The pointer to the struct device will be returned from the call.

 * Any further sysfs files that might be required can be created using this

 * pointer.

 *

 * Returns &struct device pointer on success, or ERR_PTR() on error.

 *

 * Note: the struct class passed to this function must have previously

 * been created with a call to class_create().

 */

struct device *device_create_vargs(struct class *class, struct device *parent,

				   dev_t devt, void *drvdata, const char *fmt,

				   va_list args)

{

	return device_create_groups_vargs(class, parent, devt, drvdata, NULL,

					  fmt, args);

}

EXPORT_SYMBOL_GPL(device_create_vargs);



/**
@@ -1767,6 +1778,50 @@ struct device *device_create(struct class *class, struct device *parent, 
}

EXPORT_SYMBOL_GPL(device_create);



/**

 * device_create_with_groups - creates a device and registers it with sysfs

 * @class: pointer to the struct class that this device should be registered to

 * @parent: pointer to the parent struct device of this new device, if any

 * @devt: the dev_t for the char device to be added

 * @drvdata: the data to be added to the device for callbacks

 * @groups: NULL-terminated list of attribute groups to be created

 * @fmt: string for the device's name

 *

 * This function can be used by char device classes.  A struct device

 * will be created in sysfs, registered to the specified class.

 * Additional attributes specified in the groups parameter will also

 * be created automatically.

 *

 * A "dev" file will be created, showing the dev_t for the device, if

 * the dev_t is not 0,0.

 * If a pointer to a parent struct device is passed in, the newly created

 * struct device will be a child of that device in sysfs.

 * The pointer to the struct device will be returned from the call.

 * Any further sysfs files that might be required can be created using this

 * pointer.

 *

 * Returns &struct device pointer on success, or ERR_PTR() on error.

 *

 * Note: the struct class passed to this function must have previously

 * been created with a call to class_create().

 */

struct device *device_create_with_groups(struct class *class,

					 struct device *parent, dev_t devt,

					 void *drvdata,

					 const struct attribute_group **groups,

					 const char *fmt, ...)

{

	va_list vargs;

	struct device *dev;



	va_start(vargs, fmt);

	dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,

					 fmt, vargs);

	va_end(vargs);

	return dev;

}

EXPORT_SYMBOL_GPL(device_create_with_groups);



static int __match_devt(struct device *dev, const void *data)

{

	const dev_t *devt = data;

include/linux/device.h

+5 −0
Original line number Diff line number Diff line
@@ -938,6 +938,11 @@ extern __printf(5, 6) 
struct device *device_create(struct class *cls, struct device *parent,

			     dev_t devt, void *drvdata,

			     const char *fmt, ...);

extern __printf(6, 7)

struct device *device_create_with_groups(struct class *cls,

			     struct device *parent, dev_t devt, void *drvdata,

			     const struct attribute_group **groups,

			     const char *fmt, ...);

extern void device_destroy(struct class *cls, dev_t devt);



/*

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