drivers/s390/char/tape_class.c

Source file repositories/reference/linux-study-clean/drivers/s390/char/tape_class.c

File Facts

System
Linux kernel
Corpus path
drivers/s390/char/tape_class.c
Extension
.c
Size
2675 bytes
Lines
121
Domain
Driver Families
Bucket
drivers/s390
Inferred role
Driver Families: operation-table or driver-model contract
Status
pattern implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

const struct file_operations *fops,
	char *			device_name,
	char *			mode_name)
{
	struct tape_class_device *	tcd;
	int		rc;
	char *		s;

	tcd = kzalloc_obj(struct tape_class_device);
	if (!tcd)
		return ERR_PTR(-ENOMEM);

	strscpy(tcd->device_name, device_name, TAPECLASS_NAME_LEN);
	for (s = strchr(tcd->device_name, '/'); s; s = strchr(s, '/'))
		*s = '!';
	strscpy(tcd->mode_name, mode_name, TAPECLASS_NAME_LEN);
	for (s = strchr(tcd->mode_name, '/'); s; s = strchr(s, '/'))
		*s = '!';

	tcd->char_device = cdev_alloc();
	if (!tcd->char_device) {
		rc = -ENOMEM;
		goto fail_with_tcd;
	}

	tcd->char_device->owner = fops->owner;
	tcd->char_device->ops   = fops;

	rc = cdev_add(tcd->char_device, dev, 1);
	if (rc)
		goto fail_with_cdev;

	tcd->class_device = device_create(&tape_class, device,
					  tcd->char_device->dev, NULL,
					  "%s", tcd->device_name);
	rc = PTR_ERR_OR_ZERO(tcd->class_device);
	if (rc)
		goto fail_with_cdev;
	rc = sysfs_create_link(
		&device->kobj,
		&tcd->class_device->kobj,
		tcd->mode_name
	);
	if (rc)
		goto fail_with_class_device;

	return tcd;

fail_with_class_device:
	device_destroy(&tape_class, tcd->char_device->dev);

fail_with_cdev:
	cdev_del(tcd->char_device);

fail_with_tcd:
	kfree(tcd);

	return ERR_PTR(rc);
}
EXPORT_SYMBOL(register_tape_dev);

void unregister_tape_dev(struct device *device, struct tape_class_device *tcd)
{
	if (tcd != NULL && !IS_ERR(tcd)) {
		sysfs_remove_link(&device->kobj, tcd->mode_name);
		device_destroy(&tape_class, tcd->char_device->dev);
		cdev_del(tcd->char_device);
		kfree(tcd);
	}
}
EXPORT_SYMBOL(unregister_tape_dev);

int tape_class_init(void)
{
	return class_register(&tape_class);
}

void tape_class_exit(void)
{
	class_unregister(&tape_class);
}

Annotation

Implementation Notes