linux-master/fs/char_dev.c

21 #include <linux/cdev.h>
40 	struct cdev *cdev;		/* will die */
248  * __register_chrdev() - create and register a cdev occupying a range of minors
273 	struct cdev *cdev;
280 	cdev = cdev_alloc();
281 	if (!cdev)
284 	cdev->owner = fops->owner;
285 	cdev->ops = fops;
286 	kobject_set_name(&cdev->kobj, "%s", name);
288 	err = cdev_add(cdev, MKDEV(cd->major, baseminor), count);
292 	cd->cdev = cdev;
296 	kobject_put(&cdev->kobj);
325  * __unregister_chrdev - unregister and destroy a cdev
328  * @count: the number of minor numbers this cdev is occupying
331  * Unregister and destroy the cdev occupying the region described by
341 	if (cd && cd->cdev)
342 		cdev_del(cd->cdev);
348 static struct kobject *cdev_get(struct cdev *p)
361 void cdev_put(struct cdev *p)
376 	struct cdev *p;
377 	struct cdev *new = NULL;
389 		new = container_of(kobj, struct cdev, kobj);
435 static void cdev_purge(struct cdev *cdev)
438 	while (!list_empty(&cdev->list)) {
440 		inode = container_of(cdev->list.next, struct inode, i_devices);
459 	struct cdev *p = data;
465 	struct cdev *p = data;
471  * @p: the cdev structure for the device
479 int cdev_add(struct cdev *p, dev_t dev, unsigned count)
508  * @p: the cdev structure
512  * appropriately so the parent is not freed before the cdev. This
515 void cdev_set_parent(struct cdev *p, struct kobject *kobj)
525  * @cdev: the cdev structure
527  * cdev_device_add() adds the char device represented by @cdev to the system,
532  * all references to the cdev are released.
535  * it will not add the cdev and it will be equivalent to device_add.
537  * This function should be used whenever the struct cdev and the
541  * NOTE: Callers must assume that userspace was able to open the cdev and
542  * can call cdev fops callbacks at any time, even if this function fails.
544 int cdev_device_add(struct cdev *cdev, struct device *dev)
549 		cdev_set_parent(cdev, &dev->kobj);
551 		rc = cdev_add(cdev, dev->devt, 1);
558 		cdev_del(cdev);
566  * @cdev: the cdev structure
571  * If dev->devt is not set it will not remove the cdev and will be equivalent
578 void cdev_device_del(struct cdev *cdev, struct device *dev)
582 		cdev_del(cdev);
591  * cdev_del() - remove a cdev from the system
592  * @p: the cdev structure to be removed
597  * NOTE: This guarantees that cdev device will no longer be able to be
601 void cdev_del(struct cdev *p)
610 	struct cdev *p = container_of(kobj, struct cdev, kobj);
619 	struct cdev *p = container_of(kobj, struct cdev, kobj);
636  * cdev_alloc() - allocate a cdev structure
638  * Allocates and returns a cdev structure, or NULL on failure.
640 struct cdev *cdev_alloc(void)
642 	struct cdev *p = kzalloc(sizeof(struct cdev), GFP_KERNEL);
651  * cdev_init() - initialize a cdev structure
652  * @cdev: the structure to initialize
655  * Initializes @cdev, remembering @fops, making it ready to add to the
658 void cdev_init(struct cdev *cdev, const struct file_operations *fops)
660 	memset(cdev, 0, sizeof *cdev);
661 	INIT_LIST_HEAD(&cdev->list);
662 	kobject_init(&cdev->kobj, &ktype_cdev_default);
663 	cdev->ops = fops;