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kernel/linux-rt-4.4.41/drivers/s390/char/tape_class.c 2.89 KB
5113f6f70   김현기   kernel add
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  /*
   * Copyright IBM Corp. 2004
   *
   * Tape class device support
   *
   * Author: Stefan Bader <shbader@de.ibm.com>
   * Based on simple class device code by Greg K-H
   */
  
  #define KMSG_COMPONENT "tape"
  #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  
  #include <linux/slab.h>
  
  #include "tape_class.h"
  
  MODULE_AUTHOR("Stefan Bader <shbader@de.ibm.com>");
  MODULE_DESCRIPTION(
  	"Copyright IBM Corp. 2004   All Rights Reserved.
  "
  	"tape_class.c"
  );
  MODULE_LICENSE("GPL");
  
  static struct class *tape_class;
  
  /*
   * Register a tape device and return a pointer to the cdev structure.
   *
   * device
   *	The pointer to the struct device of the physical (base) device.
   * drivername
   *	The pointer to the drivers name for it's character devices.
   * dev
   *	The intended major/minor number. The major number may be 0 to
   *	get a dynamic major number.
   * fops
   *	The pointer to the drivers file operations for the tape device.
   * devname
   *	The pointer to the name of the character device.
   */
  struct tape_class_device *register_tape_dev(
  	struct device *		device,
  	dev_t			dev,
  	const struct file_operations *fops,
  	char *			device_name,
  	char *			mode_name)
  {
  	struct tape_class_device *	tcd;
  	int		rc;
  	char *		s;
  
  	tcd = kzalloc(sizeof(struct tape_class_device), GFP_KERNEL);
  	if (!tcd)
  		return ERR_PTR(-ENOMEM);
  
  	strncpy(tcd->device_name, device_name, TAPECLASS_NAME_LEN);
  	for (s = strchr(tcd->device_name, '/'); s; s = strchr(s, '/'))
  		*s = '!';
  	strncpy(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;
  	tcd->char_device->dev   = dev;
  
  	rc = cdev_add(tcd->char_device, 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_RET(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);
  
  
  static int __init tape_init(void)
  {
  	tape_class = class_create(THIS_MODULE, "tape390");
  
  	return 0;
  }
  
  static void __exit tape_exit(void)
  {
  	class_destroy(tape_class);
  	tape_class = NULL;
  }
  
  postcore_initcall(tape_init);
  module_exit(tape_exit);